X-Git-Url: http://nitlanguage.org

diff --git a/c_src/parser_prod.sep.3.c b/c_src/parser_prod.sep.3.c
index b38ffac..caa4505 100644
--- a/c_src/parser_prod.sep.3.c
+++ b/c_src/parser_prod.sep.3.c
@@ -1,4 +1,109 @@
 #include "parser_prod.sep.0.h"
+/* method parser_prod#AIfexprExpr#empty_init for (self: Object) */
+void VIRTUAL_parser_prod__AIfexprExpr__empty_init(val* self) {
+parser_prod__AIfexprExpr__empty_init(self);
+RET_LABEL:;
+}
+/* method parser_prod#AIfexprExpr#init_aifexprexpr for (self: AIfexprExpr, nullable TKwif, nullable AExpr, nullable TKwthen, nullable AExpr, nullable TKwelse, nullable AExpr) */
+void parser_prod__AIfexprExpr__init_aifexprexpr(val* self, val* p0, val* p1, val* p2, val* p3, val* p4, val* p5) {
+val* var_n_kwif /* var n_kwif: nullable TKwif */;
+val* var_n_expr /* var n_expr: nullable AExpr */;
+val* var_n_kwthen /* var n_kwthen: nullable TKwthen */;
+val* var_n_then /* var n_then: nullable AExpr */;
+val* var_n_kwelse /* var n_kwelse: nullable TKwelse */;
+val* var_n_else /* var n_else: nullable AExpr */;
+var_n_kwif = p0;
+var_n_expr = p1;
+var_n_kwthen = p2;
+var_n_then = p3;
+var_n_kwelse = p4;
+var_n_else = p5;
+((void (*)(val*))(self->class->vft[COLOR_parser_prod__AIfexprExpr__empty_init]))(self) /* empty_init on <self:AIfexprExpr>*/;
+if (var_n_kwif == NULL) {
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5108);
+show_backtrace(1);
+}
+self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwif].val = var_n_kwif; /* _n_kwif on <self:AIfexprExpr> */
+if (var_n_kwif == NULL) {
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5109);
+show_backtrace(1);
+} else {
+((void (*)(val*, val*))(var_n_kwif->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwif, self) /* parent= on <var_n_kwif:nullable TKwif>*/;
+}
+if (var_n_expr == NULL) {
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5110);
+show_backtrace(1);
+}
+self->attrs[COLOR_parser_nodes__AIfexprExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AIfexprExpr> */
+if (var_n_expr == NULL) {
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5111);
+show_backtrace(1);
+} else {
+((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
+}
+if (var_n_kwthen == NULL) {
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5112);
+show_backtrace(1);
+}
+self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwthen].val = var_n_kwthen; /* _n_kwthen on <self:AIfexprExpr> */
+if (var_n_kwthen == NULL) {
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5113);
+show_backtrace(1);
+} else {
+((void (*)(val*, val*))(var_n_kwthen->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwthen, self) /* parent= on <var_n_kwthen:nullable TKwthen>*/;
+}
+if (var_n_then == NULL) {
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5114);
+show_backtrace(1);
+}
+self->attrs[COLOR_parser_nodes__AIfexprExpr___n_then].val = var_n_then; /* _n_then on <self:AIfexprExpr> */
+if (var_n_then == NULL) {
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5115);
+show_backtrace(1);
+} else {
+((void (*)(val*, val*))(var_n_then->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_then, self) /* parent= on <var_n_then:nullable AExpr>*/;
+}
+if (var_n_kwelse == NULL) {
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5116);
+show_backtrace(1);
+}
+self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwelse].val = var_n_kwelse; /* _n_kwelse on <self:AIfexprExpr> */
+if (var_n_kwelse == NULL) {
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5117);
+show_backtrace(1);
+} else {
+((void (*)(val*, val*))(var_n_kwelse->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwelse, self) /* parent= on <var_n_kwelse:nullable TKwelse>*/;
+}
+if (var_n_else == NULL) {
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5118);
+show_backtrace(1);
+}
+self->attrs[COLOR_parser_nodes__AIfexprExpr___n_else].val = var_n_else; /* _n_else on <self:AIfexprExpr> */
+if (var_n_else == NULL) {
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5119);
+show_backtrace(1);
+} else {
+((void (*)(val*, val*))(var_n_else->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_else, self) /* parent= on <var_n_else:nullable AExpr>*/;
+}
+RET_LABEL:;
+}
+/* method parser_prod#AIfexprExpr#init_aifexprexpr for (self: Object, nullable TKwif, nullable AExpr, nullable TKwthen, nullable AExpr, nullable TKwelse, nullable AExpr) */
+void VIRTUAL_parser_prod__AIfexprExpr__init_aifexprexpr(val* self, val* p0, val* p1, val* p2, val* p3, val* p4, val* p5) {
+parser_prod__AIfexprExpr__init_aifexprexpr(self, p0, p1, p2, p3, p4, p5);
+RET_LABEL:;
+}
 /* method parser_prod#AIfexprExpr#replace_child for (self: AIfexprExpr, ANode, nullable ANode) */
 void parser_prod__AIfexprExpr__replace_child(val* self, val* p0, val* p1) {
 val* var_old_child /* var old_child: ANode */;
@@ -49,8 +154,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwif].val; /* _n_kwif on <self:AIfexprExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwif", "src/parser/parser_prod.nit", 5271);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwif");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5124);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwif>*/;
 if (var1){
@@ -71,21 +177,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5274);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5127);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwif].val = var_new_child; /* _n_kwif on <self:AIfexprExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5277);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5130);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_expr].val; /* _n_expr on <self:AIfexprExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5281);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5134);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -106,21 +215,24 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5284);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5137);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIfexprExpr___n_expr].val = var_new_child; /* _n_expr on <self:AIfexprExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5287);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5140);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var12 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwthen].val; /* _n_kwthen on <self:AIfexprExpr> */
 if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwthen", "src/parser/parser_prod.nit", 5291);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwthen");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5144);
+show_backtrace(1);
 }
 var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:TKwthen>*/;
 if (var13){
@@ -141,21 +253,24 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5294);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5147);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwthen].val = var_new_child; /* _n_kwthen on <self:AIfexprExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5297);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5150);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var19 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_then].val; /* _n_then on <self:AIfexprExpr> */
 if (var19 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_then", "src/parser/parser_prod.nit", 5301);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_then");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5154);
+show_backtrace(1);
 }
 var20 = ((short int (*)(val*, val*))(var19->class->vft[COLOR_kernel__Object___61d_61d]))(var19, var_old_child) /* == on <var19:AExpr>*/;
 if (var20){
@@ -176,21 +291,24 @@ var23 = 0;
 var23 = var_new_child->type->type_table[cltype24] == idtype25;
 }
 if (!var23) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5304);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5157);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIfexprExpr___n_then].val = var_new_child; /* _n_then on <self:AIfexprExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5307);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5160);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var26 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwelse].val; /* _n_kwelse on <self:AIfexprExpr> */
 if (var26 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwelse", "src/parser/parser_prod.nit", 5311);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwelse");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5164);
+show_backtrace(1);
 }
 var27 = ((short int (*)(val*, val*))(var26->class->vft[COLOR_kernel__Object___61d_61d]))(var26, var_old_child) /* == on <var26:TKwelse>*/;
 if (var27){
@@ -211,21 +329,24 @@ var30 = 0;
 var30 = var_new_child->type->type_table[cltype31] == idtype32;
 }
 if (!var30) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5314);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5167);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwelse].val = var_new_child; /* _n_kwelse on <self:AIfexprExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5317);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5170);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var33 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_else].val; /* _n_else on <self:AIfexprExpr> */
 if (var33 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_else", "src/parser/parser_prod.nit", 5321);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_else");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5174);
+show_backtrace(1);
 }
 var34 = ((short int (*)(val*, val*))(var33->class->vft[COLOR_kernel__Object___61d_61d]))(var33, var_old_child) /* == on <var33:AExpr>*/;
 if (var34){
@@ -246,13 +367,15 @@ var37 = 0;
 var37 = var_new_child->type->type_table[cltype38] == idtype39;
 }
 if (!var37) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5324);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5177);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIfexprExpr___n_else].val = var_new_child; /* _n_else on <self:AIfexprExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5327);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5180);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -354,38 +477,44 @@ val* var5 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwif].val; /* _n_kwif on <self:AIfexprExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwif", "src/parser/parser_prod.nit", 5367);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwif");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5220);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_expr].val; /* _n_expr on <self:AIfexprExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5368);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5221);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwthen].val; /* _n_kwthen on <self:AIfexprExpr> */
 if (var2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwthen", "src/parser/parser_prod.nit", 5369);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwthen");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5222);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var2) /* enter_visit on <var_v:Visitor>*/;
 var3 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_then].val; /* _n_then on <self:AIfexprExpr> */
 if (var3 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_then", "src/parser/parser_prod.nit", 5370);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_then");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5223);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var3) /* enter_visit on <var_v:Visitor>*/;
 var4 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_kwelse].val; /* _n_kwelse on <self:AIfexprExpr> */
 if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwelse", "src/parser/parser_prod.nit", 5371);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwelse");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5224);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var4) /* enter_visit on <var_v:Visitor>*/;
 var5 = self->attrs[COLOR_parser_nodes__AIfexprExpr___n_else].val; /* _n_else on <self:AIfexprExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_else", "src/parser/parser_prod.nit", 5372);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_else");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5225);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var5) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -422,35 +551,41 @@ var_n_block = p3;
 var_n_label = p4;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AWhileExpr__empty_init]))(self) /* empty_init on <self:AWhileExpr>*/;
 if (var_n_kwwhile == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5387);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5240);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwwhile].val = var_n_kwwhile; /* _n_kwwhile on <self:AWhileExpr> */
 if (var_n_kwwhile == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5388);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5241);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwwhile->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwwhile, self) /* parent= on <var_n_kwwhile:nullable TKwwhile>*/;
 }
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5389);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5242);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AWhileExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AWhileExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5390);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5243);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_kwdo == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5391);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5244);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwdo].val = var_n_kwdo; /* _n_kwdo on <self:AWhileExpr> */
 if (var_n_kwdo == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5392);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5245);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwdo->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwdo, self) /* parent= on <var_n_kwdo:nullable TKwdo>*/;
 }
@@ -528,8 +663,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwwhile].val; /* _n_kwwhile on <self:AWhileExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwwhile", "src/parser/parser_prod.nit", 5405);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwwhile");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5258);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwwhile>*/;
 if (var1){
@@ -550,21 +686,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5408);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5261);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwwhile].val = var_new_child; /* _n_kwwhile on <self:AWhileExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5411);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5264);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AWhileExpr___n_expr].val; /* _n_expr on <self:AWhileExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5415);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5268);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -585,21 +724,24 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5418);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5271);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AWhileExpr___n_expr].val = var_new_child; /* _n_expr on <self:AWhileExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5421);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5274);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var12 = self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwdo].val; /* _n_kwdo on <self:AWhileExpr> */
 if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwdo", "src/parser/parser_prod.nit", 5425);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwdo");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5278);
+show_backtrace(1);
 }
 var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:TKwdo>*/;
 if (var13){
@@ -620,13 +762,15 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5428);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5281);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwdo].val = var_new_child; /* _n_kwdo on <self:AWhileExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5431);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5284);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -655,8 +799,9 @@ var23 = 0;
 var23 = var_new_child->type->type_table[cltype24] == idtype25;
 }
 if (!var23) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5438);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5291);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AWhileExpr___n_block].val = var_new_child; /* _n_block on <self:AWhileExpr> */
 } else {
@@ -690,8 +835,9 @@ var31 = 0;
 var31 = var_new_child->type->type_table[cltype32] == idtype33;
 }
 if (!var31) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5448);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5301);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ALabelable___n_label].val = var_new_child; /* _n_label on <self:AWhileExpr> */
 } else {
@@ -812,20 +958,23 @@ val* var10 /* : nullable ALabel */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwwhile].val; /* _n_kwwhile on <self:AWhileExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwwhile", "src/parser/parser_prod.nit", 5490);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwwhile");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5343);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AWhileExpr___n_expr].val; /* _n_expr on <self:AWhileExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5491);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5344);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__AWhileExpr___n_kwdo].val; /* _n_kwdo on <self:AWhileExpr> */
 if (var2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwdo", "src/parser/parser_prod.nit", 5492);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwdo");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5345);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var2) /* enter_visit on <var_v:Visitor>*/;
 var3 = self->attrs[COLOR_parser_nodes__AWhileExpr___n_block].val; /* _n_block on <self:AWhileExpr> */
@@ -838,8 +987,9 @@ var5 = 1; /* arg is null and recv is not */
 if (var5){
 var6 = self->attrs[COLOR_parser_nodes__AWhileExpr___n_block].val; /* _n_block on <self:AWhileExpr> */
 if (var6 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5494);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5347);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var6) /* enter_visit on <var_v:Visitor>*/;
 } else {
@@ -854,8 +1004,9 @@ var9 = 1; /* arg is null and recv is not */
 if (var9){
 var10 = self->attrs[COLOR_parser_nodes__ALabelable___n_label].val; /* _n_label on <self:AWhileExpr> */
 if (var10 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5497);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5350);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var10) /* enter_visit on <var_v:Visitor>*/;
 } else {
@@ -890,13 +1041,15 @@ var_n_block = p1;
 var_n_label = p2;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ALoopExpr__empty_init]))(self) /* empty_init on <self:ALoopExpr>*/;
 if (var_n_kwloop == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5511);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5364);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ALoopExpr___n_kwloop].val = var_n_kwloop; /* _n_kwloop on <self:ALoopExpr> */
 if (var_n_kwloop == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5512);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5365);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwloop->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwloop, self) /* parent= on <var_n_kwloop:nullable TKwloop>*/;
 }
@@ -960,8 +1113,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ALoopExpr___n_kwloop].val; /* _n_kwloop on <self:ALoopExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwloop", "src/parser/parser_prod.nit", 5525);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwloop");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5378);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwloop>*/;
 if (var1){
@@ -982,13 +1136,15 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5528);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5381);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ALoopExpr___n_kwloop].val = var_new_child; /* _n_kwloop on <self:ALoopExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5531);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5384);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -1017,8 +1173,9 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5538);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5391);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ALoopExpr___n_block].val = var_new_child; /* _n_block on <self:ALoopExpr> */
 } else {
@@ -1052,8 +1209,9 @@ var17 = 0;
 var17 = var_new_child->type->type_table[cltype18] == idtype19;
 }
 if (!var17) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5548);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5401);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ALabelable___n_label].val = var_new_child; /* _n_label on <self:ALoopExpr> */
 } else {
@@ -1146,8 +1304,9 @@ val* var8 /* : nullable ALabel */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ALoopExpr___n_kwloop].val; /* _n_kwloop on <self:ALoopExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwloop", "src/parser/parser_prod.nit", 5580);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwloop");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5433);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ALoopExpr___n_block].val; /* _n_block on <self:ALoopExpr> */
@@ -1160,8 +1319,9 @@ var3 = 1; /* arg is null and recv is not */
 if (var3){
 var4 = self->attrs[COLOR_parser_nodes__ALoopExpr___n_block].val; /* _n_block on <self:ALoopExpr> */
 if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5582);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5435);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var4) /* enter_visit on <var_v:Visitor>*/;
 } else {
@@ -1176,8 +1336,9 @@ var7 = 1; /* arg is null and recv is not */
 if (var7){
 var8 = self->attrs[COLOR_parser_nodes__ALabelable___n_label].val; /* _n_label on <self:ALoopExpr> */
 if (var8 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5585);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5438);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var8) /* enter_visit on <var_v:Visitor>*/;
 } else {
@@ -1226,13 +1387,15 @@ var_n_block = p4;
 var_n_label = p5;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AForExpr__empty_init]))(self) /* empty_init on <self:AForExpr>*/;
 if (var_n_kwfor == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5602);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5455);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AForExpr___n_kwfor].val = var_n_kwfor; /* _n_kwfor on <self:AForExpr> */
 if (var_n_kwfor == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5603);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5456);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwfor->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwfor, self) /* parent= on <var_n_kwfor:nullable TKwfor>*/;
 }
@@ -1251,13 +1414,15 @@ var3 = 0;
 var3 = var_n->type->type_table[cltype] == idtype;
 }
 if (!var3) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5605);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5458);
+show_backtrace(1);
 }
 var4 = self->attrs[COLOR_parser_nodes__AForExpr___n_ids].val; /* _n_ids on <self:AForExpr> */
 if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_ids", "src/parser/parser_prod.nit", 5606);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_ids");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5459);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var4->class->vft[COLOR_abstract_collection__SimpleCollection__add]))(var4, var_n) /* add on <var4:ANodes[TId]>*/;
 ((void (*)(val*, val*))(var_n->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n, self) /* parent= on <var_n:Object(TId)>*/;
@@ -1266,24 +1431,28 @@ CONTINUE_label: (void)0;
 }
 BREAK_label: (void)0;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5609);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5462);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AForExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AForExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5610);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5463);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_kwdo == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5611);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5464);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AForExpr___n_kwdo].val = var_n_kwdo; /* _n_kwdo on <self:AForExpr> */
 if (var_n_kwdo == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5612);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5465);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwdo->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwdo, self) /* parent= on <var_n_kwdo:nullable TKwdo>*/;
 }
@@ -1382,8 +1551,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AForExpr___n_kwfor].val; /* _n_kwfor on <self:AForExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwfor", "src/parser/parser_prod.nit", 5625);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwfor");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5478);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwfor>*/;
 if (var1){
@@ -1404,13 +1574,15 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5628);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5481);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AForExpr___n_kwfor].val = var_new_child; /* _n_kwfor on <self:AForExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5631);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5484);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -1419,14 +1591,14 @@ var5 = NEW_range__Range(&type_range__Rangekernel__Int);
 var6 = 0;
 var7 = self->attrs[COLOR_parser_nodes__AForExpr___n_ids].val; /* _n_ids on <self:AForExpr> */
 if (var7 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_ids", "src/parser/parser_prod.nit", 5635);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_ids");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5488);
+show_backtrace(1);
 }
 var8 = ((long (*)(val*))(var7->class->vft[COLOR_abstract_collection__Collection__length]))(var7) /* length on <var7:ANodes[TId]>*/;
 var9 = BOX_kernel__Int(var6); /* autobox from Int to Discrete */
 var10 = BOX_kernel__Int(var8); /* autobox from Int to Discrete */
 ((void (*)(val*, val*, val*))(var5->class->vft[COLOR_range__Range__without_last]))(var5, var9, var10) /* without_last on <var5:Range[Int]>*/;
-CHECK_NEW_range__Range(var5);
 var11 = ((val* (*)(val*))(var5->class->vft[COLOR_abstract_collection__Collection__iterator]))(var5) /* iterator on <var5:Range[Int]>*/;
 for(;;) {
 var12 = ((short int (*)(val*))(var11->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var11) /* is_ok on <var11:Iterator[nullable Object]>*/;
@@ -1436,8 +1608,9 @@ var14 = ((struct instance_kernel__Int*)var13)->value; /* autounbox from nullable
 var_i = var14;
 var15 = self->attrs[COLOR_parser_nodes__AForExpr___n_ids].val; /* _n_ids on <self:AForExpr> */
 if (var15 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_ids", "src/parser/parser_prod.nit", 5636);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_ids");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5489);
+show_backtrace(1);
 }
 var16 = ((val* (*)(val*, long))(var15->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(var15, var_i) /* [] on <var15:ANodes[TId]>*/;
 var17 = ((short int (*)(val*, val*))(var16->class->vft[COLOR_kernel__Object___61d_61d]))(var16, var_old_child) /* == on <var16:nullable Object(TId)>*/;
@@ -1458,21 +1631,24 @@ var20 = 0;
 var20 = var_new_child->type->type_table[cltype21] == idtype22;
 }
 if (!var20) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5638);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5491);
+show_backtrace(1);
 }
 var23 = self->attrs[COLOR_parser_nodes__AForExpr___n_ids].val; /* _n_ids on <self:AForExpr> */
 if (var23 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_ids", "src/parser/parser_prod.nit", 5639);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_ids");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5492);
+show_backtrace(1);
 }
 ((void (*)(val*, long, val*))(var23->class->vft[COLOR_abstract_collection__Sequence___91d_93d_61d]))(var23, var_i, var_new_child) /* []= on <var23:ANodes[TId]>*/;
 ((void (*)(val*, val*))(var_new_child->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_new_child, self) /* parent= on <var_new_child:nullable ANode(TId)>*/;
 } else {
 var24 = self->attrs[COLOR_parser_nodes__AForExpr___n_ids].val; /* _n_ids on <self:AForExpr> */
 if (var24 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_ids", "src/parser/parser_prod.nit", 5642);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_ids");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5495);
+show_backtrace(1);
 }
 ((void (*)(val*, long))(var24->class->vft[COLOR_abstract_collection__Sequence__remove_at]))(var24, var_i) /* remove_at on <var24:ANodes[TId]>*/;
 }
@@ -1485,8 +1661,9 @@ CONTINUE_label: (void)0;
 BREAK_label: (void)0;
 var25 = self->attrs[COLOR_parser_nodes__AForExpr___n_expr].val; /* _n_expr on <self:AForExpr> */
 if (var25 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5647);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5500);
+show_backtrace(1);
 }
 var26 = ((short int (*)(val*, val*))(var25->class->vft[COLOR_kernel__Object___61d_61d]))(var25, var_old_child) /* == on <var25:AExpr>*/;
 if (var26){
@@ -1507,21 +1684,24 @@ var29 = 0;
 var29 = var_new_child->type->type_table[cltype30] == idtype31;
 }
 if (!var29) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5650);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5503);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AForExpr___n_expr].val = var_new_child; /* _n_expr on <self:AForExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5653);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5506);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var32 = self->attrs[COLOR_parser_nodes__AForExpr___n_kwdo].val; /* _n_kwdo on <self:AForExpr> */
 if (var32 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwdo", "src/parser/parser_prod.nit", 5657);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwdo");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5510);
+show_backtrace(1);
 }
 var33 = ((short int (*)(val*, val*))(var32->class->vft[COLOR_kernel__Object___61d_61d]))(var32, var_old_child) /* == on <var32:TKwdo>*/;
 if (var33){
@@ -1542,13 +1722,15 @@ var36 = 0;
 var36 = var_new_child->type->type_table[cltype37] == idtype38;
 }
 if (!var36) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5660);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5513);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AForExpr___n_kwdo].val = var_new_child; /* _n_kwdo on <self:AForExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5663);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5516);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -1577,8 +1759,9 @@ var43 = 0;
 var43 = var_new_child->type->type_table[cltype44] == idtype45;
 }
 if (!var43) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5670);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5523);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AForExpr___n_block].val = var_new_child; /* _n_block on <self:AForExpr> */
 } else {
@@ -1612,8 +1795,9 @@ var51 = 0;
 var51 = var_new_child->type->type_table[cltype52] == idtype53;
 }
 if (!var51) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5680);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5533);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ALabelable___n_label].val = var_new_child; /* _n_label on <self:AForExpr> */
 } else {
@@ -1739,14 +1923,16 @@ val* var14 /* : nullable ALabel */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AForExpr___n_kwfor].val; /* _n_kwfor on <self:AForExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwfor", "src/parser/parser_prod.nit", 5722);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwfor");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5575);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AForExpr___n_ids].val; /* _n_ids on <self:AForExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_ids", "src/parser/parser_prod.nit", 5723);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_ids");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5576);
+show_backtrace(1);
 }
 var2 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__Collection__iterator]))(var1) /* iterator on <var1:ANodes[TId]>*/;
 for(;;) {
@@ -1761,14 +1947,16 @@ CONTINUE_label: (void)0;
 BREAK_label: (void)0;
 var5 = self->attrs[COLOR_parser_nodes__AForExpr___n_expr].val; /* _n_expr on <self:AForExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5726);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5579);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var5) /* enter_visit on <var_v:Visitor>*/;
 var6 = self->attrs[COLOR_parser_nodes__AForExpr___n_kwdo].val; /* _n_kwdo on <self:AForExpr> */
 if (var6 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwdo", "src/parser/parser_prod.nit", 5727);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwdo");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5580);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var6) /* enter_visit on <var_v:Visitor>*/;
 var7 = self->attrs[COLOR_parser_nodes__AForExpr___n_block].val; /* _n_block on <self:AForExpr> */
@@ -1781,8 +1969,9 @@ var9 = 1; /* arg is null and recv is not */
 if (var9){
 var10 = self->attrs[COLOR_parser_nodes__AForExpr___n_block].val; /* _n_block on <self:AForExpr> */
 if (var10 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5729);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5582);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var10) /* enter_visit on <var_v:Visitor>*/;
 } else {
@@ -1797,8 +1986,9 @@ var13 = 1; /* arg is null and recv is not */
 if (var13){
 var14 = self->attrs[COLOR_parser_nodes__ALabelable___n_label].val; /* _n_label on <self:AForExpr> */
 if (var14 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5732);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5585);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var14) /* enter_visit on <var_v:Visitor>*/;
 } else {
@@ -1835,13 +2025,15 @@ var_n_expr = p2;
 var_n_else = p3;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AAssertExpr__empty_init]))(self) /* empty_init on <self:AAssertExpr>*/;
 if (var_n_kwassert == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5747);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5600);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssertExpr___n_kwassert].val = var_n_kwassert; /* _n_kwassert on <self:AAssertExpr> */
 if (var_n_kwassert == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5748);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5601);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwassert->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwassert, self) /* parent= on <var_n_kwassert:nullable TKwassert>*/;
 }
@@ -1857,13 +2049,15 @@ if (var1){
 } else {
 }
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5753);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5606);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssertExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AAssertExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5754);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5607);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
@@ -1923,8 +2117,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AAssertExpr___n_kwassert].val; /* _n_kwassert on <self:AAssertExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwassert", "src/parser/parser_prod.nit", 5763);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwassert");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5616);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwassert>*/;
 if (var1){
@@ -1945,13 +2140,15 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5766);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5619);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssertExpr___n_kwassert].val = var_new_child; /* _n_kwassert on <self:AAssertExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5769);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5622);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -1980,8 +2177,9 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5776);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5629);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssertExpr___n_id].val = var_new_child; /* _n_id on <self:AAssertExpr> */
 } else {
@@ -1993,8 +2191,9 @@ goto RET_LABEL;
 }
 var13 = self->attrs[COLOR_parser_nodes__AAssertExpr___n_expr].val; /* _n_expr on <self:AAssertExpr> */
 if (var13 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5783);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5636);
+show_backtrace(1);
 }
 var14 = ((short int (*)(val*, val*))(var13->class->vft[COLOR_kernel__Object___61d_61d]))(var13, var_old_child) /* == on <var13:AExpr>*/;
 if (var14){
@@ -2015,13 +2214,15 @@ var17 = 0;
 var17 = var_new_child->type->type_table[cltype18] == idtype19;
 }
 if (!var17) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5786);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5639);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssertExpr___n_expr].val = var_new_child; /* _n_expr on <self:AAssertExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5789);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5642);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -2050,8 +2251,9 @@ var24 = 0;
 var24 = var_new_child->type->type_table[cltype25] == idtype26;
 }
 if (!var24) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5796);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5649);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssertExpr___n_else].val = var_new_child; /* _n_else on <self:AAssertExpr> */
 } else {
@@ -2158,8 +2360,9 @@ val* var9 /* : nullable AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AAssertExpr___n_kwassert].val; /* _n_kwassert on <self:AAssertExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwassert", "src/parser/parser_prod.nit", 5833);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwassert");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5686);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AAssertExpr___n_id].val; /* _n_id on <self:AAssertExpr> */
@@ -2172,16 +2375,18 @@ var3 = 1; /* arg is null and recv is not */
 if (var3){
 var4 = self->attrs[COLOR_parser_nodes__AAssertExpr___n_id].val; /* _n_id on <self:AAssertExpr> */
 if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5835);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5688);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var4) /* enter_visit on <var_v:Visitor>*/;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AAssertExpr___n_expr].val; /* _n_expr on <self:AAssertExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5837);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5690);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var5) /* enter_visit on <var_v:Visitor>*/;
 var6 = self->attrs[COLOR_parser_nodes__AAssertExpr___n_else].val; /* _n_else on <self:AAssertExpr> */
@@ -2194,8 +2399,9 @@ var8 = 1; /* arg is null and recv is not */
 if (var8){
 var9 = self->attrs[COLOR_parser_nodes__AAssertExpr___n_else].val; /* _n_else on <self:AAssertExpr> */
 if (var9 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5839);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5692);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var9) /* enter_visit on <var_v:Visitor>*/;
 } else {
@@ -2224,24 +2430,28 @@ var_n_kwonce = p0;
 var_n_expr = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AOnceExpr__empty_init]))(self) /* empty_init on <self:AOnceExpr>*/;
 if (var_n_kwonce == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5852);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5705);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOnceExpr___n_kwonce].val = var_n_kwonce; /* _n_kwonce on <self:AOnceExpr> */
 if (var_n_kwonce == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5853);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5706);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwonce->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwonce, self) /* parent= on <var_n_kwonce:nullable TKwonce>*/;
 }
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5854);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5707);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AProxyExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AOnceExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5855);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5708);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
@@ -2274,8 +2484,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AOnceExpr___n_kwonce].val; /* _n_kwonce on <self:AOnceExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwonce", "src/parser/parser_prod.nit", 5860);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwonce");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5713);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwonce>*/;
 if (var1){
@@ -2296,21 +2507,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5863);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5716);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOnceExpr___n_kwonce].val = var_new_child; /* _n_kwonce on <self:AOnceExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5866);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5719);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AProxyExpr___n_expr].val; /* _n_expr on <self:AOnceExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5870);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5723);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -2331,13 +2545,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5873);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5726);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AProxyExpr___n_expr].val = var_new_child; /* _n_expr on <self:AOnceExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5876);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5729);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -2383,14 +2599,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AOnceExpr___n_kwonce].val; /* _n_kwonce on <self:AOnceExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwonce", "src/parser/parser_prod.nit", 5896);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwonce");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5749);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AProxyExpr___n_expr].val; /* _n_expr on <self:AOnceExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5897);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5750);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -2415,13 +2633,15 @@ val* var_n_expr /* var n_expr: nullable AExpr */;
 var_n_expr = p0;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ASendExpr__empty_init]))(self) /* empty_init on <self:ASendExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5908);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5761);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ASendExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5909);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5762);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
@@ -2447,8 +2667,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ASendExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5914);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5767);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -2469,13 +2690,15 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5917);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5770);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ASendExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5920);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5773);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -2507,8 +2730,9 @@ val* var /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ASendExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5935);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5788);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -2535,24 +2759,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ABinopExpr__empty_init]))(self) /* empty_init on <self:ABinopExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5947);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5800);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ABinopExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5948);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5801);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 5949);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5802);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:ABinopExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 5950);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5803);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -2585,8 +2813,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ABinopExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5955);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5808);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -2607,21 +2836,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5958);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5811);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ABinopExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5961);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5814);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ABinopExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 5965);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5818);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -2642,13 +2874,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 5968);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5821);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:ABinopExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 5971);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5824);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -2694,14 +2928,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ABinopExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 5991);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5844);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ABinopExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 5992);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5845);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -2728,24 +2964,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AOrExpr__empty_init]))(self) /* empty_init on <self:AOrExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6004);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5857);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AOrExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6005);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5858);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6006);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5859);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AOrExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6007);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5860);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -2778,8 +3018,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AOrExpr___n_expr].val; /* _n_expr on <self:AOrExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6012);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5865);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -2800,21 +3041,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6015);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5868);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrExpr___n_expr].val = var_new_child; /* _n_expr on <self:AOrExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6018);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5871);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AOrExpr___n_expr2].val; /* _n_expr2 on <self:AOrExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6022);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5875);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -2835,13 +3079,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6025);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5878);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AOrExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6028);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5881);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -2887,14 +3133,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AOrExpr___n_expr].val; /* _n_expr on <self:AOrExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6048);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5901);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AOrExpr___n_expr2].val; /* _n_expr2 on <self:AOrExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6049);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5902);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -2921,24 +3169,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AAndExpr__empty_init]))(self) /* empty_init on <self:AAndExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6061);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5914);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAndExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AAndExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6062);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5915);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6063);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5916);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAndExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AAndExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6064);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5917);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -2971,8 +3223,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AAndExpr___n_expr].val; /* _n_expr on <self:AAndExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6069);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5922);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -2993,21 +3246,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6072);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5925);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAndExpr___n_expr].val = var_new_child; /* _n_expr on <self:AAndExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6075);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5928);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AAndExpr___n_expr2].val; /* _n_expr2 on <self:AAndExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6079);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5932);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -3028,13 +3284,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6082);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5935);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAndExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AAndExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6085);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5938);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -3080,14 +3338,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AAndExpr___n_expr].val; /* _n_expr on <self:AAndExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6105);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5958);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AAndExpr___n_expr2].val; /* _n_expr2 on <self:AAndExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6106);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5959);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -3114,24 +3374,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AOrElseExpr__empty_init]))(self) /* empty_init on <self:AOrElseExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6118);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5971);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AOrElseExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6119);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5972);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6120);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5973);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AOrElseExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6121);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5974);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -3164,8 +3428,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr].val; /* _n_expr on <self:AOrElseExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6126);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5979);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -3186,21 +3451,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6129);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5982);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr].val = var_new_child; /* _n_expr on <self:AOrElseExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6132);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5985);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr2].val; /* _n_expr2 on <self:AOrElseExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6136);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5989);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -3221,13 +3489,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6139);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5992);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AOrElseExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6142);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 5995);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -3273,14 +3543,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr].val; /* _n_expr on <self:AOrElseExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6162);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6015);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AOrElseExpr___n_expr2].val; /* _n_expr2 on <self:AOrElseExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6163);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6016);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -3307,24 +3579,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AImpliesExpr__empty_init]))(self) /* empty_init on <self:AImpliesExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6175);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6028);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AImpliesExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6176);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6029);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6177);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6030);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AImpliesExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6178);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6031);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -3357,8 +3633,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr].val; /* _n_expr on <self:AImpliesExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6183);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6036);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -3379,21 +3656,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6186);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6039);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr].val = var_new_child; /* _n_expr on <self:AImpliesExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6189);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6042);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr2].val; /* _n_expr2 on <self:AImpliesExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6193);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6046);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -3414,13 +3694,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6196);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6049);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AImpliesExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6199);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6052);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -3466,14 +3748,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr].val; /* _n_expr on <self:AImpliesExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6219);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6072);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AImpliesExpr___n_expr2].val; /* _n_expr2 on <self:AImpliesExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6220);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6073);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -3500,24 +3784,28 @@ var_n_kwnot = p0;
 var_n_expr = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ANotExpr__empty_init]))(self) /* empty_init on <self:ANotExpr>*/;
 if (var_n_kwnot == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6232);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6085);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANotExpr___n_kwnot].val = var_n_kwnot; /* _n_kwnot on <self:ANotExpr> */
 if (var_n_kwnot == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6233);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6086);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwnot->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwnot, self) /* parent= on <var_n_kwnot:nullable TKwnot>*/;
 }
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6234);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6087);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANotExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ANotExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6235);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6088);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
@@ -3550,8 +3838,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ANotExpr___n_kwnot].val; /* _n_kwnot on <self:ANotExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwnot", "src/parser/parser_prod.nit", 6240);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwnot");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6093);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwnot>*/;
 if (var1){
@@ -3572,21 +3861,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6243);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6096);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANotExpr___n_kwnot].val = var_new_child; /* _n_kwnot on <self:ANotExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6246);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6099);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ANotExpr___n_expr].val; /* _n_expr on <self:ANotExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6250);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6103);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -3607,13 +3899,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6253);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6106);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANotExpr___n_expr].val = var_new_child; /* _n_expr on <self:ANotExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6256);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6109);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -3659,14 +3953,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ANotExpr___n_kwnot].val; /* _n_kwnot on <self:ANotExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwnot", "src/parser/parser_prod.nit", 6276);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwnot");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6129);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ANotExpr___n_expr].val; /* _n_expr on <self:ANotExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6277);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6130);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -3693,24 +3989,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AEqExpr__empty_init]))(self) /* empty_init on <self:AEqExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6289);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6142);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AEqExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6290);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6143);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6291);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6144);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AEqExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6292);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6145);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -3743,8 +4043,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AEqExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6297);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6150);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -3765,21 +4066,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6300);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6153);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AEqExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6303);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6156);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AEqExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6307);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6160);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -3800,13 +4104,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6310);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6163);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AEqExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6313);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6166);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -3852,14 +4158,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AEqExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6333);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6186);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AEqExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6334);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6187);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -3869,199 +4177,6 @@ void VIRTUAL_parser_prod__AEqExpr__visit_all(val* self, val* p0) {
 parser_prod__AEqExpr__visit_all(self, p0);
 RET_LABEL:;
 }
-/* method parser_prod#AEeExpr#empty_init for (self: AEeExpr) */
-void parser_prod__AEeExpr__empty_init(val* self) {
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#empty_init for (self: Object) */
-void VIRTUAL_parser_prod__AEeExpr__empty_init(val* self) {
-parser_prod__AEeExpr__empty_init(self);
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#init_aeeexpr for (self: AEeExpr, nullable AExpr, nullable AExpr) */
-void parser_prod__AEeExpr__init_aeeexpr(val* self, val* p0, val* p1) {
-val* var_n_expr /* var n_expr: nullable AExpr */;
-val* var_n_expr2 /* var n_expr2: nullable AExpr */;
-var_n_expr = p0;
-var_n_expr2 = p1;
-((void (*)(val*))(self->class->vft[COLOR_parser_prod__AEeExpr__empty_init]))(self) /* empty_init on <self:AEeExpr>*/;
-if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6346);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AEeExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AEeExpr> */
-if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6347);
-exit(1);
-} else {
-((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
-}
-if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6348);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AEeExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AEeExpr> */
-if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6349);
-exit(1);
-} else {
-((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
-}
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#init_aeeexpr for (self: Object, nullable AExpr, nullable AExpr) */
-void VIRTUAL_parser_prod__AEeExpr__init_aeeexpr(val* self, val* p0, val* p1) {
-parser_prod__AEeExpr__init_aeeexpr(self, p0, p1);
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#replace_child for (self: AEeExpr, ANode, nullable ANode) */
-void parser_prod__AEeExpr__replace_child(val* self, val* p0, val* p1) {
-val* var_old_child /* var old_child: ANode */;
-val* var_new_child /* var new_child: nullable ANode */;
-val* var /* : AExpr */;
-short int var1 /* : Bool */;
-val* var2 /* : null */;
-short int var3 /* : Bool */;
-short int var4 /* : Bool */;
-int cltype;
-int idtype;
-val* var5 /* : AExpr */;
-short int var6 /* : Bool */;
-val* var7 /* : null */;
-short int var8 /* : Bool */;
-short int var9 /* : Bool */;
-int cltype10;
-int idtype11;
-var_old_child = p0;
-var_new_child = p1;
-var = self->attrs[COLOR_parser_nodes__AEeExpr___n_expr].val; /* _n_expr on <self:AEeExpr> */
-if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6354);
-exit(1);
-}
-var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
-if (var1){
-var2 = NULL;
-if (var_new_child == NULL) {
-var3 = 0; /* is null */
-} else {
-var3 = 1; /* arg is null and recv is not */
-}
-if (var3){
-((void (*)(val*, val*))(var_new_child->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_new_child, self) /* parent= on <var_new_child:nullable ANode(ANode)>*/;
-/* <var_new_child:nullable ANode(ANode)> isa AExpr */
-cltype = type_parser_nodes__AExpr.color;
-idtype = type_parser_nodes__AExpr.id;
-if(cltype >= var_new_child->type->table_size) {
-var4 = 0;
-} else {
-var4 = var_new_child->type->type_table[cltype] == idtype;
-}
-if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6357);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AEeExpr___n_expr].val = var_new_child; /* _n_expr on <self:AEeExpr> */
-} else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6360);
-exit(1);
-}
-goto RET_LABEL;
-} else {
-}
-var5 = self->attrs[COLOR_parser_nodes__AEeExpr___n_expr2].val; /* _n_expr2 on <self:AEeExpr> */
-if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6364);
-exit(1);
-}
-var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
-if (var6){
-var7 = NULL;
-if (var_new_child == NULL) {
-var8 = 0; /* is null */
-} else {
-var8 = 1; /* arg is null and recv is not */
-}
-if (var8){
-((void (*)(val*, val*))(var_new_child->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_new_child, self) /* parent= on <var_new_child:nullable ANode(ANode)>*/;
-/* <var_new_child:nullable ANode(ANode)> isa AExpr */
-cltype10 = type_parser_nodes__AExpr.color;
-idtype11 = type_parser_nodes__AExpr.id;
-if(cltype10 >= var_new_child->type->table_size) {
-var9 = 0;
-} else {
-var9 = var_new_child->type->type_table[cltype10] == idtype11;
-}
-if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6367);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AEeExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AEeExpr> */
-} else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6370);
-exit(1);
-}
-goto RET_LABEL;
-} else {
-}
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#replace_child for (self: Object, ANode, nullable ANode) */
-void VIRTUAL_parser_prod__AEeExpr__replace_child(val* self, val* p0, val* p1) {
-parser_prod__AEeExpr__replace_child(self, p0, p1);
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#n_expr= for (self: AEeExpr, AExpr) */
-void parser_prod__AEeExpr__n_expr_61d(val* self, val* p0) {
-val* var_node /* var node: AExpr */;
-var_node = p0;
-self->attrs[COLOR_parser_nodes__AEeExpr___n_expr].val = var_node; /* _n_expr on <self:AEeExpr> */
-((void (*)(val*, val*))(var_node->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_node, self) /* parent= on <var_node:AExpr>*/;
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#n_expr= for (self: Object, AExpr) */
-void VIRTUAL_parser_prod__AEeExpr__n_expr_61d(val* self, val* p0) {
-parser_prod__AEeExpr__n_expr_61d(self, p0);
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#n_expr2= for (self: AEeExpr, AExpr) */
-void parser_prod__AEeExpr__n_expr2_61d(val* self, val* p0) {
-val* var_node /* var node: AExpr */;
-var_node = p0;
-self->attrs[COLOR_parser_nodes__AEeExpr___n_expr2].val = var_node; /* _n_expr2 on <self:AEeExpr> */
-((void (*)(val*, val*))(var_node->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_node, self) /* parent= on <var_node:AExpr>*/;
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#n_expr2= for (self: Object, AExpr) */
-void VIRTUAL_parser_prod__AEeExpr__n_expr2_61d(val* self, val* p0) {
-parser_prod__AEeExpr__n_expr2_61d(self, p0);
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#visit_all for (self: AEeExpr, Visitor) */
-void parser_prod__AEeExpr__visit_all(val* self, val* p0) {
-val* var_v /* var v: Visitor */;
-val* var /* : AExpr */;
-val* var1 /* : AExpr */;
-var_v = p0;
-var = self->attrs[COLOR_parser_nodes__AEeExpr___n_expr].val; /* _n_expr on <self:AEeExpr> */
-if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6390);
-exit(1);
-}
-((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
-var1 = self->attrs[COLOR_parser_nodes__AEeExpr___n_expr2].val; /* _n_expr2 on <self:AEeExpr> */
-if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6391);
-exit(1);
-}
-((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
-RET_LABEL:;
-}
-/* method parser_prod#AEeExpr#visit_all for (self: Object, Visitor) */
-void VIRTUAL_parser_prod__AEeExpr__visit_all(val* self, val* p0) {
-parser_prod__AEeExpr__visit_all(self, p0);
-RET_LABEL:;
-}
 /* method parser_prod#ANeExpr#empty_init for (self: ANeExpr) */
 void parser_prod__ANeExpr__empty_init(val* self) {
 RET_LABEL:;
@@ -4079,24 +4194,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ANeExpr__empty_init]))(self) /* empty_init on <self:ANeExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6403);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6199);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ANeExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6404);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6200);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6405);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6201);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:ANeExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6406);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6202);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -4129,8 +4248,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ANeExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6411);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6207);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -4151,21 +4271,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6414);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6210);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ANeExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6417);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6213);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ANeExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6421);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6217);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -4186,13 +4309,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6424);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6220);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:ANeExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6427);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6223);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -4238,14 +4363,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ANeExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6447);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6243);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ANeExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6448);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6244);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -4272,24 +4399,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ALtExpr__empty_init]))(self) /* empty_init on <self:ALtExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6460);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6256);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ALtExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6461);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6257);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6462);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6258);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:ALtExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6463);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6259);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -4322,8 +4453,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ALtExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6468);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6264);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -4344,21 +4476,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6471);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6267);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ALtExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6474);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6270);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ALtExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6478);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6274);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -4379,13 +4514,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6481);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6277);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:ALtExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6484);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6280);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -4431,14 +4568,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ALtExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6504);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6300);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ALtExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6505);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6301);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -4465,24 +4604,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ALeExpr__empty_init]))(self) /* empty_init on <self:ALeExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6517);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6313);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ALeExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6518);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6314);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6519);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6315);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:ALeExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6520);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6316);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -4515,8 +4658,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ALeExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6525);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6321);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -4537,21 +4681,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6528);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6324);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ALeExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6531);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6327);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ALeExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6535);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6331);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -4572,13 +4719,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6538);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6334);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:ALeExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6541);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6337);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -4624,14 +4773,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ALeExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6561);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6357);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ALeExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6562);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6358);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -4658,24 +4809,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ALlExpr__empty_init]))(self) /* empty_init on <self:ALlExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6574);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6370);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ALlExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6575);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6371);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6576);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6372);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:ALlExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6577);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6373);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -4708,8 +4863,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ALlExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6582);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6378);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -4730,21 +4886,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6585);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6381);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ALlExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6588);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6384);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ALlExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6592);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6388);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -4765,13 +4924,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6595);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6391);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:ALlExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6598);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6394);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -4817,14 +4978,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ALlExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6618);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6414);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ALlExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6619);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6415);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -4851,24 +5014,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AGtExpr__empty_init]))(self) /* empty_init on <self:AGtExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6631);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6427);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AGtExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6632);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6428);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6633);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6429);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AGtExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6634);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6430);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -4901,8 +5068,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AGtExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6639);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6435);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -4923,21 +5091,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6642);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6438);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AGtExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6645);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6441);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AGtExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6649);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6445);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -4958,13 +5129,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6652);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6448);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AGtExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6655);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6451);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -5010,14 +5183,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AGtExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6675);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6471);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AGtExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6676);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6472);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -5044,24 +5219,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AGeExpr__empty_init]))(self) /* empty_init on <self:AGeExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6688);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6484);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AGeExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6689);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6485);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6690);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6486);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AGeExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6691);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6487);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -5094,8 +5273,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AGeExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6696);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6492);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -5116,21 +5296,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6699);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6495);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AGeExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6702);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6498);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AGeExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6706);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6502);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -5151,13 +5334,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6709);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6505);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AGeExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6712);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6508);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -5203,14 +5388,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AGeExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6732);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6528);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AGeExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6733);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6529);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -5237,24 +5424,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AGgExpr__empty_init]))(self) /* empty_init on <self:AGgExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6745);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6541);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AGgExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6746);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6542);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6747);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6543);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AGgExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6748);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6544);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -5287,8 +5478,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AGgExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6753);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6549);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -5309,21 +5501,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6756);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6552);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AGgExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6759);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6555);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AGgExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6763);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6559);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -5344,13 +5539,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6766);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6562);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AGgExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6769);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6565);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -5396,14 +5593,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AGgExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6789);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6585);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AGgExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6790);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6586);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -5430,24 +5629,28 @@ var_n_expr = p0;
 var_n_type = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AIsaExpr__empty_init]))(self) /* empty_init on <self:AIsaExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6802);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6598);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIsaExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AIsaExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6803);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6599);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_type == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6804);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6600);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIsaExpr___n_type].val = var_n_type; /* _n_type on <self:AIsaExpr> */
 if (var_n_type == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6805);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6601);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_type->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_type, self) /* parent= on <var_n_type:nullable AType>*/;
 }
@@ -5480,8 +5683,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AIsaExpr___n_expr].val; /* _n_expr on <self:AIsaExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6810);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6606);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -5502,21 +5706,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6813);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6609);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIsaExpr___n_expr].val = var_new_child; /* _n_expr on <self:AIsaExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6816);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6612);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AIsaExpr___n_type].val; /* _n_type on <self:AIsaExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_type", "src/parser/parser_prod.nit", 6820);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_type");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6616);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AType>*/;
 if (var6){
@@ -5537,13 +5744,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6823);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6619);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AIsaExpr___n_type].val = var_new_child; /* _n_type on <self:AIsaExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6826);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6622);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -5589,14 +5798,16 @@ val* var1 /* : AType */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AIsaExpr___n_expr].val; /* _n_expr on <self:AIsaExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6846);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6642);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AIsaExpr___n_type].val; /* _n_type on <self:AIsaExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_type", "src/parser/parser_prod.nit", 6847);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_type");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6643);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -5623,24 +5834,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__APlusExpr__empty_init]))(self) /* empty_init on <self:APlusExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6859);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6655);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:APlusExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6860);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6656);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6861);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6657);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:APlusExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6862);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6658);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -5673,8 +5888,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:APlusExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6867);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6663);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -5695,21 +5911,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6870);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6666);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:APlusExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6873);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6669);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:APlusExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6877);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6673);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -5730,13 +5949,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6880);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6676);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:APlusExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6883);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6679);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -5782,14 +6003,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:APlusExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6903);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6699);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:APlusExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6904);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6700);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -5816,24 +6039,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AMinusExpr__empty_init]))(self) /* empty_init on <self:AMinusExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6916);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6712);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AMinusExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6917);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6713);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6918);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6714);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AMinusExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6919);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6715);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -5866,8 +6093,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AMinusExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6924);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6720);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -5888,21 +6116,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6927);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6723);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AMinusExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6930);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6726);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AMinusExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6934);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6730);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -5923,13 +6154,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6937);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6733);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AMinusExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6940);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6736);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -5975,14 +6208,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AMinusExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6960);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6756);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AMinusExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6961);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6757);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -6009,24 +6244,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AStarshipExpr__empty_init]))(self) /* empty_init on <self:AStarshipExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6973);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6769);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AStarshipExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6974);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6770);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 6975);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6771);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AStarshipExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 6976);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6772);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -6059,8 +6298,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AStarshipExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 6981);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6777);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -6081,21 +6321,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6984);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6780);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AStarshipExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6987);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6783);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AStarshipExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 6991);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6787);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -6116,13 +6359,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 6994);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6790);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AStarshipExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 6997);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6793);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -6168,14 +6413,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AStarshipExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7017);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6813);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AStarshipExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 7018);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6814);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -6202,24 +6449,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AStarExpr__empty_init]))(self) /* empty_init on <self:AStarExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7030);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6826);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AStarExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7031);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6827);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7032);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6828);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:AStarExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7033);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6829);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -6252,8 +6503,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AStarExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7038);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6834);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -6274,21 +6526,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7041);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6837);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AStarExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7044);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6840);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AStarExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 7048);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6844);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -6309,13 +6564,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7051);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6847);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:AStarExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7054);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6850);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -6361,14 +6618,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AStarExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7074);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6870);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:AStarExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 7075);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6871);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -6395,24 +6654,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ASlashExpr__empty_init]))(self) /* empty_init on <self:ASlashExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7087);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6883);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ASlashExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7088);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6884);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7089);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6885);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:ASlashExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7090);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6886);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -6445,8 +6708,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ASlashExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7095);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6891);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -6467,21 +6731,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7098);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6894);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ASlashExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7101);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6897);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ASlashExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 7105);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6901);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -6502,13 +6769,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7108);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6904);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:ASlashExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7111);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6907);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -6554,14 +6823,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ASlashExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7131);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6927);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:ASlashExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 7132);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6928);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -6588,24 +6859,28 @@ var_n_expr = p0;
 var_n_expr2 = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__APercentExpr__empty_init]))(self) /* empty_init on <self:APercentExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7144);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6940);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:APercentExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7145);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6941);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7146);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6942);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_n_expr2; /* _n_expr2 on <self:APercentExpr> */
 if (var_n_expr2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7147);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6943);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr2->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr2, self) /* parent= on <var_n_expr2:nullable AExpr>*/;
 }
@@ -6638,8 +6913,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:APercentExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7152);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6948);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -6660,21 +6936,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7155);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6951);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:APercentExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7158);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6954);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:APercentExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 7162);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6958);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -6695,13 +6974,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7165);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6961);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val = var_new_child; /* _n_expr2 on <self:APercentExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7168);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6964);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -6747,14 +7028,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:APercentExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7188);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6984);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ABinopExpr___n_expr2].val; /* _n_expr2 on <self:APercentExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr2", "src/parser/parser_prod.nit", 7189);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr2");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6985);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -6781,24 +7064,28 @@ var_n_minus = p0;
 var_n_expr = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AUminusExpr__empty_init]))(self) /* empty_init on <self:AUminusExpr>*/;
 if (var_n_minus == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7201);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6997);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AUminusExpr___n_minus].val = var_n_minus; /* _n_minus on <self:AUminusExpr> */
 if (var_n_minus == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7202);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6998);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_minus->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_minus, self) /* parent= on <var_n_minus:nullable TMinus>*/;
 }
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7203);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 6999);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AUminusExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7204);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7000);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
@@ -6831,8 +7118,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AUminusExpr___n_minus].val; /* _n_minus on <self:AUminusExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_minus", "src/parser/parser_prod.nit", 7209);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_minus");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7005);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TMinus>*/;
 if (var1){
@@ -6853,21 +7141,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7212);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7008);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AUminusExpr___n_minus].val = var_new_child; /* _n_minus on <self:AUminusExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7215);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7011);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AUminusExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7219);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7015);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AExpr>*/;
 if (var6){
@@ -6888,13 +7179,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7222);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7018);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AUminusExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7225);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7021);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -6940,14 +7233,16 @@ val* var1 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AUminusExpr___n_minus].val; /* _n_minus on <self:AUminusExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_minus", "src/parser/parser_prod.nit", 7245);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_minus");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7041);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AUminusExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7246);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7042);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -6980,24 +7275,28 @@ var_n_id = p2;
 var_n_args = p3;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ANewExpr__empty_init]))(self) /* empty_init on <self:ANewExpr>*/;
 if (var_n_kwnew == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7260);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7056);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANewExpr___n_kwnew].val = var_n_kwnew; /* _n_kwnew on <self:ANewExpr> */
 if (var_n_kwnew == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7261);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7057);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwnew->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwnew, self) /* parent= on <var_n_kwnew:nullable TKwnew>*/;
 }
 if (var_n_type == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7262);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7058);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANewExpr___n_type].val = var_n_type; /* _n_type on <self:ANewExpr> */
 if (var_n_type == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7263);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7059);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_type->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_type, self) /* parent= on <var_n_type:nullable AType>*/;
 }
@@ -7013,13 +7312,15 @@ if (var1){
 } else {
 }
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7268);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7064);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANewExpr___n_args].val = var_n_args; /* _n_args on <self:ANewExpr> */
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7269);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7065);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_args->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_args, self) /* parent= on <var_n_args:nullable AExprs>*/;
 }
@@ -7067,8 +7368,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ANewExpr___n_kwnew].val; /* _n_kwnew on <self:ANewExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwnew", "src/parser/parser_prod.nit", 7274);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwnew");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7070);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:TKwnew>*/;
 if (var1){
@@ -7089,21 +7391,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7277);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7073);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANewExpr___n_kwnew].val = var_new_child; /* _n_kwnew on <self:ANewExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7280);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7076);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ANewExpr___n_type].val; /* _n_type on <self:ANewExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_type", "src/parser/parser_prod.nit", 7284);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_type");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7080);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:AType>*/;
 if (var6){
@@ -7124,13 +7429,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7287);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7083);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANewExpr___n_type].val = var_new_child; /* _n_type on <self:ANewExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7290);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7086);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -7159,8 +7466,9 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7297);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7093);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANewExpr___n_id].val = var_new_child; /* _n_id on <self:ANewExpr> */
 } else {
@@ -7172,8 +7480,9 @@ goto RET_LABEL;
 }
 var20 = self->attrs[COLOR_parser_nodes__ANewExpr___n_args].val; /* _n_args on <self:ANewExpr> */
 if (var20 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7304);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7100);
+show_backtrace(1);
 }
 var21 = ((short int (*)(val*, val*))(var20->class->vft[COLOR_kernel__Object___61d_61d]))(var20, var_old_child) /* == on <var20:AExprs>*/;
 if (var21){
@@ -7194,13 +7503,15 @@ var24 = 0;
 var24 = var_new_child->type->type_table[cltype25] == idtype26;
 }
 if (!var24) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7307);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7103);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ANewExpr___n_args].val = var_new_child; /* _n_args on <self:ANewExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7310);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7106);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -7288,14 +7599,16 @@ val* var6 /* : AExprs */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ANewExpr___n_kwnew].val; /* _n_kwnew on <self:ANewExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwnew", "src/parser/parser_prod.nit", 7342);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwnew");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7138);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ANewExpr___n_type].val; /* _n_type on <self:ANewExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_type", "src/parser/parser_prod.nit", 7343);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_type");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7139);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__ANewExpr___n_id].val; /* _n_id on <self:ANewExpr> */
@@ -7308,16 +7621,18 @@ var4 = 1; /* arg is null and recv is not */
 if (var4){
 var5 = self->attrs[COLOR_parser_nodes__ANewExpr___n_id].val; /* _n_id on <self:ANewExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7345);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7141);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var5) /* enter_visit on <var_v:Visitor>*/;
 } else {
 }
 var6 = self->attrs[COLOR_parser_nodes__ANewExpr___n_args].val; /* _n_args on <self:ANewExpr> */
 if (var6 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7347);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7143);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var6) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -7344,24 +7659,28 @@ var_n_expr = p0;
 var_n_id = p1;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AAttrExpr__empty_init]))(self) /* empty_init on <self:AAttrExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7359);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7155);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AAttrExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7360);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7156);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7361);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7157);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val = var_n_id; /* _n_id on <self:AAttrExpr> */
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7362);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7158);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_id->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_id, self) /* parent= on <var_n_id:nullable TAttrid>*/;
 }
@@ -7394,8 +7713,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val; /* _n_expr on <self:AAttrExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7367);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7163);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -7416,21 +7736,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7370);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7166);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val = var_new_child; /* _n_expr on <self:AAttrExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7373);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7169);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val; /* _n_id on <self:AAttrExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7377);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7173);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:TAttrid>*/;
 if (var6){
@@ -7451,13 +7774,15 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7380);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7176);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val = var_new_child; /* _n_id on <self:AAttrExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7383);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7179);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -7503,14 +7828,16 @@ val* var1 /* : TAttrid */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val; /* _n_expr on <self:AAttrExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7403);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7199);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val; /* _n_id on <self:AAttrExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7404);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7200);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -7541,46 +7868,54 @@ var_n_assign = p2;
 var_n_value = p3;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AAttrAssignExpr__empty_init]))(self) /* empty_init on <self:AAttrAssignExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7418);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7214);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AAttrAssignExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7419);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7215);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7420);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7216);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val = var_n_id; /* _n_id on <self:AAttrAssignExpr> */
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7421);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7217);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_id->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_id, self) /* parent= on <var_n_id:nullable TAttrid>*/;
 }
 if (var_n_assign == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7422);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7218);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val = var_n_assign; /* _n_assign on <self:AAttrAssignExpr> */
 if (var_n_assign == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7423);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7219);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_assign->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_assign, self) /* parent= on <var_n_assign:nullable TAssign>*/;
 }
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7424);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7220);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val = var_n_value; /* _n_value on <self:AAttrAssignExpr> */
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7425);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7221);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_value->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_value, self) /* parent= on <var_n_value:nullable AExpr>*/;
 }
@@ -7627,8 +7962,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val; /* _n_expr on <self:AAttrAssignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7430);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7226);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -7649,21 +7985,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7433);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7229);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val = var_new_child; /* _n_expr on <self:AAttrAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7436);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7232);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val; /* _n_id on <self:AAttrAssignExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7440);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7236);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:TAttrid>*/;
 if (var6){
@@ -7684,21 +8023,24 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7443);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7239);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val = var_new_child; /* _n_id on <self:AAttrAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7446);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7242);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var12 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val; /* _n_assign on <self:AAttrAssignExpr> */
 if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign", "src/parser/parser_prod.nit", 7450);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7246);
+show_backtrace(1);
 }
 var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:TAssign>*/;
 if (var13){
@@ -7719,21 +8061,24 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7453);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7249);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val = var_new_child; /* _n_assign on <self:AAttrAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7456);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7252);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var19 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val; /* _n_value on <self:AAttrAssignExpr> */
 if (var19 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7460);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7256);
+show_backtrace(1);
 }
 var20 = ((short int (*)(val*, val*))(var19->class->vft[COLOR_kernel__Object___61d_61d]))(var19, var_old_child) /* == on <var19:AExpr>*/;
 if (var20){
@@ -7754,13 +8099,15 @@ var23 = 0;
 var23 = var_new_child->type->type_table[cltype24] == idtype25;
 }
 if (!var23) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7463);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7259);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val = var_new_child; /* _n_value on <self:AAttrAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7466);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7262);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -7834,26 +8181,30 @@ val* var3 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val; /* _n_expr on <self:AAttrAssignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7496);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7292);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val; /* _n_id on <self:AAttrAssignExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7497);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7293);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val; /* _n_assign on <self:AAttrAssignExpr> */
 if (var2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign", "src/parser/parser_prod.nit", 7498);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7294);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var2) /* enter_visit on <var_v:Visitor>*/;
 var3 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val; /* _n_value on <self:AAttrAssignExpr> */
 if (var3 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7499);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7295);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var3) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -7884,46 +8235,54 @@ var_n_assign_op = p2;
 var_n_value = p3;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__AAttrReassignExpr__empty_init]))(self) /* empty_init on <self:AAttrReassignExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7513);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7309);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AAttrReassignExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7514);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7310);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7515);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7311);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val = var_n_id; /* _n_id on <self:AAttrReassignExpr> */
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7516);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7312);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_id->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_id, self) /* parent= on <var_n_id:nullable TAttrid>*/;
 }
 if (var_n_assign_op == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7517);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7313);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val = var_n_assign_op; /* _n_assign_op on <self:AAttrReassignExpr> */
 if (var_n_assign_op == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7518);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7314);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_assign_op->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_assign_op, self) /* parent= on <var_n_assign_op:nullable AAssignOp>*/;
 }
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7519);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7315);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val = var_n_value; /* _n_value on <self:AAttrReassignExpr> */
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7520);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7316);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_value->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_value, self) /* parent= on <var_n_value:nullable AExpr>*/;
 }
@@ -7970,8 +8329,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val; /* _n_expr on <self:AAttrReassignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7525);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7321);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -7992,21 +8352,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7528);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7324);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val = var_new_child; /* _n_expr on <self:AAttrReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7531);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7327);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val; /* _n_id on <self:AAttrReassignExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7535);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7331);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:TAttrid>*/;
 if (var6){
@@ -8027,21 +8390,24 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7538);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7334);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val = var_new_child; /* _n_id on <self:AAttrReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7541);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7337);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var12 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val; /* _n_assign_op on <self:AAttrReassignExpr> */
 if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign_op", "src/parser/parser_prod.nit", 7545);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign_op");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7341);
+show_backtrace(1);
 }
 var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:AAssignOp>*/;
 if (var13){
@@ -8062,21 +8428,24 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7548);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7344);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val = var_new_child; /* _n_assign_op on <self:AAttrReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7551);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7347);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var19 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val; /* _n_value on <self:AAttrReassignExpr> */
 if (var19 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7555);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7351);
+show_backtrace(1);
 }
 var20 = ((short int (*)(val*, val*))(var19->class->vft[COLOR_kernel__Object___61d_61d]))(var19, var_old_child) /* == on <var19:AExpr>*/;
 if (var20){
@@ -8097,13 +8466,15 @@ var23 = 0;
 var23 = var_new_child->type->type_table[cltype24] == idtype25;
 }
 if (!var23) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7558);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7354);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val = var_new_child; /* _n_value on <self:AAttrReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7561);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7357);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -8177,26 +8548,30 @@ val* var3 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_expr].val; /* _n_expr on <self:AAttrReassignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7591);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7387);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__AAttrFormExpr___n_id].val; /* _n_id on <self:AAttrReassignExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7592);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7388);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val; /* _n_assign_op on <self:AAttrReassignExpr> */
 if (var2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign_op", "src/parser/parser_prod.nit", 7593);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign_op");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7389);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var2) /* enter_visit on <var_v:Visitor>*/;
 var3 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val; /* _n_value on <self:AAttrReassignExpr> */
 if (var3 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7594);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7390);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var3) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -8215,92 +8590,59 @@ void VIRTUAL_parser_prod__ACallExpr__empty_init(val* self) {
 parser_prod__ACallExpr__empty_init(self);
 RET_LABEL:;
 }
-/* method parser_prod#ACallExpr#init_acallexpr for (self: ACallExpr, nullable AExpr, nullable TId, nullable AExprs, Collection[Object]) */
-void parser_prod__ACallExpr__init_acallexpr(val* self, val* p0, val* p1, val* p2, val* p3) {
+/* method parser_prod#ACallExpr#init_acallexpr for (self: ACallExpr, nullable AExpr, nullable TId, nullable AExprs) */
+void parser_prod__ACallExpr__init_acallexpr(val* self, val* p0, val* p1, val* p2) {
 val* var_n_expr /* var n_expr: nullable AExpr */;
 val* var_n_id /* var n_id: nullable TId */;
 val* var_n_args /* var n_args: nullable AExprs */;
-val* var_n_closure_defs /* var n_closure_defs: Collection[Object] */;
-val* var /* : Iterator[nullable Object] */;
-short int var1 /* : Bool */;
-val* var2 /* : nullable Object */;
-val* var_n /* var n: Object */;
-short int var3 /* : Bool */;
-int cltype;
-int idtype;
-val* var4 /* : ANodes[AClosureDef] */;
 var_n_expr = p0;
 var_n_id = p1;
 var_n_args = p2;
-var_n_closure_defs = p3;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ACallExpr__empty_init]))(self) /* empty_init on <self:ACallExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7608);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7403);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ACallExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7609);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7404);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7610);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7405);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val = var_n_id; /* _n_id on <self:ACallExpr> */
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7611);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7406);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_id->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_id, self) /* parent= on <var_n_id:nullable TId>*/;
 }
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7612);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7407);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val = var_n_args; /* _n_args on <self:ACallExpr> */
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7613);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7408);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_args->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_args, self) /* parent= on <var_n_args:nullable AExprs>*/;
 }
-var = ((val* (*)(val*))(var_n_closure_defs->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_n_closure_defs) /* iterator on <var_n_closure_defs:Collection[Object]>*/;
-for(;;) {
-var1 = ((short int (*)(val*))(var->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var) /* is_ok on <var:Iterator[nullable Object]>*/;
-if(!var1) break;
-var2 = ((val* (*)(val*))(var->class->vft[COLOR_abstract_collection__Iterator__item]))(var) /* item on <var:Iterator[nullable Object]>*/;
-var_n = var2;
-/* <var_n:Object> isa AClosureDef */
-cltype = type_parser_nodes__AClosureDef.color;
-idtype = type_parser_nodes__AClosureDef.id;
-if(cltype >= var_n->type->table_size) {
-var3 = 0;
-} else {
-var3 = var_n->type->type_table[cltype] == idtype;
-}
-if (!var3) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7615);
-exit(1);
-}
-var4 = self->attrs[COLOR_parser_nodes__ASendExpr___n_closure_defs].val; /* _n_closure_defs on <self:ACallExpr> */
-if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_closure_defs", "src/parser/parser_prod.nit", 7616);
-exit(1);
-}
-((void (*)(val*, val*))(var4->class->vft[COLOR_abstract_collection__SimpleCollection__add]))(var4, var_n) /* add on <var4:ANodes[AClosureDef]>*/;
-((void (*)(val*, val*))(var_n->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n, self) /* parent= on <var_n:Object(AClosureDef)>*/;
-CONTINUE_label: (void)0;
-((void (*)(val*))(var->class->vft[COLOR_abstract_collection__Iterator__next]))(var) /* next on <var:Iterator[nullable Object]>*/;
-}
-BREAK_label: (void)0;
 RET_LABEL:;
 }
-/* method parser_prod#ACallExpr#init_acallexpr for (self: Object, nullable AExpr, nullable TId, nullable AExprs, Collection[Object]) */
-void VIRTUAL_parser_prod__ACallExpr__init_acallexpr(val* self, val* p0, val* p1, val* p2, val* p3) {
-parser_prod__ACallExpr__init_acallexpr(self, p0, p1, p2, p3);
+/* method parser_prod#ACallExpr#init_acallexpr for (self: Object, nullable AExpr, nullable TId, nullable AExprs) */
+void VIRTUAL_parser_prod__ACallExpr__init_acallexpr(val* self, val* p0, val* p1, val* p2) {
+parser_prod__ACallExpr__init_acallexpr(self, p0, p1, p2);
 RET_LABEL:;
 }
 /* method parser_prod#ACallExpr#replace_child for (self: ACallExpr, ANode, nullable ANode) */
@@ -8328,33 +8670,13 @@ short int var15 /* : Bool */;
 short int var16 /* : Bool */;
 int cltype17;
 int idtype18;
-val* var19 /* : Range[Int] */;
-long var20 /* : Int */;
-val* var21 /* : ANodes[AClosureDef] */;
-long var22 /* : Int */;
-val* var23 /* : Discrete */;
-val* var24 /* : Discrete */;
-val* var25 /* : Iterator[nullable Object] */;
-short int var26 /* : Bool */;
-val* var27 /* : nullable Object */;
-long var_i /* var i: Int */;
-long var28 /* : Int */;
-val* var29 /* : ANodes[AClosureDef] */;
-val* var30 /* : nullable Object */;
-short int var31 /* : Bool */;
-val* var32 /* : null */;
-short int var33 /* : Bool */;
-short int var34 /* : Bool */;
-int cltype35;
-int idtype36;
-val* var37 /* : ANodes[AClosureDef] */;
-val* var38 /* : ANodes[AClosureDef] */;
 var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ACallExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7623);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7413);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -8375,21 +8697,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7626);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7416);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ACallExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7629);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7419);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val; /* _n_id on <self:ACallExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7633);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7423);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:TId>*/;
 if (var6){
@@ -8410,21 +8735,24 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7636);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7426);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val = var_new_child; /* _n_id on <self:ACallExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7639);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7429);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var12 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val; /* _n_args on <self:ACallExpr> */
 if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7643);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7433);
+show_backtrace(1);
 }
 var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:AExprs>*/;
 if (var13){
@@ -8445,85 +8773,19 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7646);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7436);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val = var_new_child; /* _n_args on <self:ACallExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7649);
-exit(1);
-}
-goto RET_LABEL;
-} else {
-}
-var19 = NEW_range__Range(&type_range__Rangekernel__Int);
-var20 = 0;
-var21 = self->attrs[COLOR_parser_nodes__ASendExpr___n_closure_defs].val; /* _n_closure_defs on <self:ACallExpr> */
-if (var21 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_closure_defs", "src/parser/parser_prod.nit", 7653);
-exit(1);
-}
-var22 = ((long (*)(val*))(var21->class->vft[COLOR_abstract_collection__Collection__length]))(var21) /* length on <var21:ANodes[AClosureDef]>*/;
-var23 = BOX_kernel__Int(var20); /* autobox from Int to Discrete */
-var24 = BOX_kernel__Int(var22); /* autobox from Int to Discrete */
-((void (*)(val*, val*, val*))(var19->class->vft[COLOR_range__Range__without_last]))(var19, var23, var24) /* without_last on <var19:Range[Int]>*/;
-CHECK_NEW_range__Range(var19);
-var25 = ((val* (*)(val*))(var19->class->vft[COLOR_abstract_collection__Collection__iterator]))(var19) /* iterator on <var19:Range[Int]>*/;
-for(;;) {
-var26 = ((short int (*)(val*))(var25->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var25) /* is_ok on <var25:Iterator[nullable Object]>*/;
-if(!var26) break;
-var27 = ((val* (*)(val*))(var25->class->vft[COLOR_abstract_collection__Iterator__item]))(var25) /* item on <var25:Iterator[nullable Object]>*/;
-var28 = ((struct instance_kernel__Int*)var27)->value; /* autounbox from nullable Object to Int */;
-var_i = var28;
-var29 = self->attrs[COLOR_parser_nodes__ASendExpr___n_closure_defs].val; /* _n_closure_defs on <self:ACallExpr> */
-if (var29 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_closure_defs", "src/parser/parser_prod.nit", 7654);
-exit(1);
-}
-var30 = ((val* (*)(val*, long))(var29->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(var29, var_i) /* [] on <var29:ANodes[AClosureDef]>*/;
-var31 = ((short int (*)(val*, val*))(var30->class->vft[COLOR_kernel__Object___61d_61d]))(var30, var_old_child) /* == on <var30:nullable Object(AClosureDef)>*/;
-if (var31){
-var32 = NULL;
-if (var_new_child == NULL) {
-var33 = 0; /* is null */
-} else {
-var33 = 1; /* arg is null and recv is not */
-}
-if (var33){
-/* <var_new_child:nullable ANode(ANode)> isa AClosureDef */
-cltype35 = type_parser_nodes__AClosureDef.color;
-idtype36 = type_parser_nodes__AClosureDef.id;
-if(cltype35 >= var_new_child->type->table_size) {
-var34 = 0;
-} else {
-var34 = var_new_child->type->type_table[cltype35] == idtype36;
-}
-if (!var34) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7656);
-exit(1);
-}
-var37 = self->attrs[COLOR_parser_nodes__ASendExpr___n_closure_defs].val; /* _n_closure_defs on <self:ACallExpr> */
-if (var37 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_closure_defs", "src/parser/parser_prod.nit", 7657);
-exit(1);
-}
-((void (*)(val*, long, val*))(var37->class->vft[COLOR_abstract_collection__Sequence___91d_93d_61d]))(var37, var_i, var_new_child) /* []= on <var37:ANodes[AClosureDef]>*/;
-((void (*)(val*, val*))(var_new_child->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_new_child, self) /* parent= on <var_new_child:nullable ANode(AClosureDef)>*/;
-} else {
-var38 = self->attrs[COLOR_parser_nodes__ASendExpr___n_closure_defs].val; /* _n_closure_defs on <self:ACallExpr> */
-if (var38 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_closure_defs", "src/parser/parser_prod.nit", 7660);
-exit(1);
-}
-((void (*)(val*, long))(var38->class->vft[COLOR_abstract_collection__Sequence__remove_at]))(var38, var_i) /* remove_at on <var38:ANodes[AClosureDef]>*/;
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7439);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
-CONTINUE_label: (void)0;
-((void (*)(val*))(var25->class->vft[COLOR_abstract_collection__Iterator__next]))(var25) /* next on <var25:Iterator[nullable Object]>*/;
-}
-BREAK_label: (void)0;
 RET_LABEL:;
 }
 /* method parser_prod#ACallExpr#replace_child for (self: Object, ANode, nullable ANode) */
@@ -8576,46 +8838,28 @@ val* var_v /* var v: Visitor */;
 val* var /* : AExpr */;
 val* var1 /* : TId */;
 val* var2 /* : AExprs */;
-val* var3 /* : ANodes[AClosureDef] */;
-val* var4 /* : Iterator[nullable Object] */;
-short int var5 /* : Bool */;
-val* var6 /* : nullable Object */;
-val* var_n /* var n: AClosureDef */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ACallExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7686);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7464);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val; /* _n_id on <self:ACallExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7687);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7465);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val; /* _n_args on <self:ACallExpr> */
 if (var2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7688);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7466);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var2) /* enter_visit on <var_v:Visitor>*/;
-var3 = self->attrs[COLOR_parser_nodes__ASendExpr___n_closure_defs].val; /* _n_closure_defs on <self:ACallExpr> */
-if (var3 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_closure_defs", "src/parser/parser_prod.nit", 7689);
-exit(1);
-}
-var4 = ((val* (*)(val*))(var3->class->vft[COLOR_abstract_collection__Collection__iterator]))(var3) /* iterator on <var3:ANodes[AClosureDef]>*/;
-for(;;) {
-var5 = ((short int (*)(val*))(var4->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var4) /* is_ok on <var4:Iterator[nullable Object]>*/;
-if(!var5) break;
-var6 = ((val* (*)(val*))(var4->class->vft[COLOR_abstract_collection__Iterator__item]))(var4) /* item on <var4:Iterator[nullable Object]>*/;
-var_n = var6;
-((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var_n) /* enter_visit on <var_v:Visitor>*/;
-CONTINUE_label: (void)0;
-((void (*)(val*))(var4->class->vft[COLOR_abstract_collection__Iterator__next]))(var4) /* next on <var4:Iterator[nullable Object]>*/;
-}
-BREAK_label: (void)0;
 RET_LABEL:;
 }
 /* method parser_prod#ACallExpr#visit_all for (self: Object, Visitor) */
@@ -8646,57 +8890,67 @@ var_n_assign = p3;
 var_n_value = p4;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ACallAssignExpr__empty_init]))(self) /* empty_init on <self:ACallAssignExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7706);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7481);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ACallAssignExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7707);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7482);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7708);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7483);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val = var_n_id; /* _n_id on <self:ACallAssignExpr> */
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7709);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7484);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_id->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_id, self) /* parent= on <var_n_id:nullable TId>*/;
 }
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7710);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7485);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val = var_n_args; /* _n_args on <self:ACallAssignExpr> */
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7711);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7486);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_args->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_args, self) /* parent= on <var_n_args:nullable AExprs>*/;
 }
 if (var_n_assign == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7712);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7487);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val = var_n_assign; /* _n_assign on <self:ACallAssignExpr> */
 if (var_n_assign == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7713);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7488);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_assign->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_assign, self) /* parent= on <var_n_assign:nullable TAssign>*/;
 }
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7714);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7489);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val = var_n_value; /* _n_value on <self:ACallAssignExpr> */
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7715);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7490);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_value->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_value, self) /* parent= on <var_n_value:nullable AExpr>*/;
 }
@@ -8750,8 +9004,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ACallAssignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7720);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7495);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -8772,21 +9027,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7723);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7498);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ACallAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7726);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7501);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val; /* _n_id on <self:ACallAssignExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7730);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7505);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:TId>*/;
 if (var6){
@@ -8807,21 +9065,24 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7733);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7508);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val = var_new_child; /* _n_id on <self:ACallAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7736);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7511);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var12 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val; /* _n_args on <self:ACallAssignExpr> */
 if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7740);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7515);
+show_backtrace(1);
 }
 var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:AExprs>*/;
 if (var13){
@@ -8842,21 +9103,24 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7743);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7518);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val = var_new_child; /* _n_args on <self:ACallAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7746);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7521);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var19 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val; /* _n_assign on <self:ACallAssignExpr> */
 if (var19 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign", "src/parser/parser_prod.nit", 7750);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7525);
+show_backtrace(1);
 }
 var20 = ((short int (*)(val*, val*))(var19->class->vft[COLOR_kernel__Object___61d_61d]))(var19, var_old_child) /* == on <var19:TAssign>*/;
 if (var20){
@@ -8877,21 +9141,24 @@ var23 = 0;
 var23 = var_new_child->type->type_table[cltype24] == idtype25;
 }
 if (!var23) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7753);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7528);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val = var_new_child; /* _n_assign on <self:ACallAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7756);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7531);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var26 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val; /* _n_value on <self:ACallAssignExpr> */
 if (var26 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7760);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7535);
+show_backtrace(1);
 }
 var27 = ((short int (*)(val*, val*))(var26->class->vft[COLOR_kernel__Object___61d_61d]))(var26, var_old_child) /* == on <var26:AExpr>*/;
 if (var27){
@@ -8912,13 +9179,15 @@ var30 = 0;
 var30 = var_new_child->type->type_table[cltype31] == idtype32;
 }
 if (!var30) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7763);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7538);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val = var_new_child; /* _n_value on <self:ACallAssignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7766);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7541);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -9006,32 +9275,37 @@ val* var4 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ACallAssignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7801);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7576);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val; /* _n_id on <self:ACallAssignExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7802);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7577);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val; /* _n_args on <self:ACallAssignExpr> */
 if (var2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7803);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7578);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var2) /* enter_visit on <var_v:Visitor>*/;
 var3 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_assign].val; /* _n_assign on <self:ACallAssignExpr> */
 if (var3 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign", "src/parser/parser_prod.nit", 7804);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7579);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var3) /* enter_visit on <var_v:Visitor>*/;
 var4 = self->attrs[COLOR_parser_nodes__AAssignFormExpr___n_value].val; /* _n_value on <self:ACallAssignExpr> */
 if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7805);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7580);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var4) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -9064,57 +9338,67 @@ var_n_assign_op = p3;
 var_n_value = p4;
 ((void (*)(val*))(self->class->vft[COLOR_parser_prod__ACallReassignExpr__empty_init]))(self) /* empty_init on <self:ACallReassignExpr>*/;
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7820);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7595);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:ACallReassignExpr> */
 if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7821);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7596);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
 }
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7822);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7597);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val = var_n_id; /* _n_id on <self:ACallReassignExpr> */
 if (var_n_id == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7823);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7598);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_id->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_id, self) /* parent= on <var_n_id:nullable TId>*/;
 }
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7824);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7599);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val = var_n_args; /* _n_args on <self:ACallReassignExpr> */
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7825);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7600);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_args->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_args, self) /* parent= on <var_n_args:nullable AExprs>*/;
 }
 if (var_n_assign_op == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7826);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7601);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val = var_n_assign_op; /* _n_assign_op on <self:ACallReassignExpr> */
 if (var_n_assign_op == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7827);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7602);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_assign_op->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_assign_op, self) /* parent= on <var_n_assign_op:nullable AAssignOp>*/;
 }
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7828);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7603);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val = var_n_value; /* _n_value on <self:ACallReassignExpr> */
 if (var_n_value == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7829);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7604);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_value->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_value, self) /* parent= on <var_n_value:nullable AExpr>*/;
 }
@@ -9168,8 +9452,9 @@ var_old_child = p0;
 var_new_child = p1;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ACallReassignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7834);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7609);
+show_backtrace(1);
 }
 var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
 if (var1){
@@ -9190,21 +9475,24 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7837);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7612);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:ACallReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7840);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7615);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var5 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val; /* _n_id on <self:ACallReassignExpr> */
 if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7844);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7619);
+show_backtrace(1);
 }
 var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:TId>*/;
 if (var6){
@@ -9225,21 +9513,24 @@ var9 = 0;
 var9 = var_new_child->type->type_table[cltype10] == idtype11;
 }
 if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7847);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7622);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val = var_new_child; /* _n_id on <self:ACallReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7850);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7625);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var12 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val; /* _n_args on <self:ACallReassignExpr> */
 if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7854);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7629);
+show_backtrace(1);
 }
 var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:AExprs>*/;
 if (var13){
@@ -9260,21 +9551,24 @@ var16 = 0;
 var16 = var_new_child->type->type_table[cltype17] == idtype18;
 }
 if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7857);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7632);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val = var_new_child; /* _n_args on <self:ACallReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7860);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7635);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var19 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val; /* _n_assign_op on <self:ACallReassignExpr> */
 if (var19 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign_op", "src/parser/parser_prod.nit", 7864);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign_op");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7639);
+show_backtrace(1);
 }
 var20 = ((short int (*)(val*, val*))(var19->class->vft[COLOR_kernel__Object___61d_61d]))(var19, var_old_child) /* == on <var19:AAssignOp>*/;
 if (var20){
@@ -9295,21 +9589,24 @@ var23 = 0;
 var23 = var_new_child->type->type_table[cltype24] == idtype25;
 }
 if (!var23) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7867);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7642);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val = var_new_child; /* _n_assign_op on <self:ACallReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7870);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7645);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var26 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val; /* _n_value on <self:ACallReassignExpr> */
 if (var26 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7874);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7649);
+show_backtrace(1);
 }
 var27 = ((short int (*)(val*, val*))(var26->class->vft[COLOR_kernel__Object___61d_61d]))(var26, var_old_child) /* == on <var26:AExpr>*/;
 if (var27){
@@ -9330,13 +9627,15 @@ var30 = 0;
 var30 = var_new_child->type->type_table[cltype31] == idtype32;
 }
 if (!var30) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7877);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7652);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val = var_new_child; /* _n_value on <self:ACallReassignExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7880);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7655);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -9424,32 +9723,37 @@ val* var4 /* : AExpr */;
 var_v = p0;
 var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:ACallReassignExpr> */
 if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 7915);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_expr");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7690);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var) /* enter_visit on <var_v:Visitor>*/;
 var1 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_id].val; /* _n_id on <self:ACallReassignExpr> */
 if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_id", "src/parser/parser_prod.nit", 7916);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_id");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7691);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var1) /* enter_visit on <var_v:Visitor>*/;
 var2 = self->attrs[COLOR_parser_nodes__ACallFormExpr___n_args].val; /* _n_args on <self:ACallReassignExpr> */
 if (var2 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7917);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7692);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var2) /* enter_visit on <var_v:Visitor>*/;
 var3 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_assign_op].val; /* _n_assign_op on <self:ACallReassignExpr> */
 if (var3 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_assign_op", "src/parser/parser_prod.nit", 7918);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_assign_op");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7693);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var3) /* enter_visit on <var_v:Visitor>*/;
 var4 = self->attrs[COLOR_parser_nodes__AReassignFormExpr___n_value].val; /* _n_value on <self:ACallReassignExpr> */
 if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_value", "src/parser/parser_prod.nit", 7919);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_value");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7694);
+show_backtrace(1);
 }
 ((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var4) /* enter_visit on <var_v:Visitor>*/;
 RET_LABEL:;
@@ -9491,24 +9795,28 @@ if (var1){
 } else {
 }
 if (var_n_kwsuper == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7936);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7711);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASuperExpr___n_kwsuper].val = var_n_kwsuper; /* _n_kwsuper on <self:ASuperExpr> */
 if (var_n_kwsuper == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7937);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7712);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_kwsuper->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwsuper, self) /* parent= on <var_n_kwsuper:nullable TKwsuper>*/;
 }
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7938);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Cast failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7713);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASuperExpr___n_args].val = var_n_args; /* _n_args on <self:ASuperExpr> */
 if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 7939);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Receiver is null");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7714);
+show_backtrace(1);
 } else {
 ((void (*)(val*, val*))(var_n_args->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_args, self) /* parent= on <var_n_args:nullable AExprs>*/;
 }
@@ -9571,8 +9879,9 @@ var4 = 0;
 var4 = var_new_child->type->type_table[cltype] == idtype;
 }
 if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7947);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7722);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASuperExpr___n_qualified].val = var_new_child; /* _n_qualified on <self:ASuperExpr> */
 } else {
@@ -9584,8 +9893,9 @@ goto RET_LABEL;
 }
 var6 = self->attrs[COLOR_parser_nodes__ASuperExpr___n_kwsuper].val; /* _n_kwsuper on <self:ASuperExpr> */
 if (var6 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwsuper", "src/parser/parser_prod.nit", 7954);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_kwsuper");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7729);
+show_backtrace(1);
 }
 var7 = ((short int (*)(val*, val*))(var6->class->vft[COLOR_kernel__Object___61d_61d]))(var6, var_old_child) /* == on <var6:TKwsuper>*/;
 if (var7){
@@ -9606,21 +9916,24 @@ var10 = 0;
 var10 = var_new_child->type->type_table[cltype11] == idtype12;
 }
 if (!var10) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7957);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7732);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASuperExpr___n_kwsuper].val = var_new_child; /* _n_kwsuper on <self:ASuperExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7960);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7735);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
 }
 var13 = self->attrs[COLOR_parser_nodes__ASuperExpr___n_args].val; /* _n_args on <self:ASuperExpr> */
 if (var13 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 7964);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _n_args");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7739);
+show_backtrace(1);
 }
 var14 = ((short int (*)(val*, val*))(var13->class->vft[COLOR_kernel__Object___61d_61d]))(var13, var_old_child) /* == on <var13:AExprs>*/;
 if (var14){
@@ -9641,13 +9954,15 @@ var17 = 0;
 var17 = var_new_child->type->type_table[cltype18] == idtype19;
 }
 if (!var17) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 7967);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Assert failed");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7742);
+show_backtrace(1);
 }
 self->attrs[COLOR_parser_nodes__ASuperExpr___n_args].val = var_new_child; /* _n_args on <self:ASuperExpr> */
 } else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 7970);
-exit(1);
+fprintf(stderr, "Runtime error: %s", "Aborted");
+fprintf(stderr, " (%s:%d)\n", "src/parser/parser_prod.nit", 7745);
+show_backtrace(1);
 }
 goto RET_LABEL;
 } else {
@@ -9683,310 +9998,3 @@ void VIRTUAL_parser_prod__ASuperExpr__n_qualified_61d(val* self, val* p0) {
 parser_prod__ASuperExpr__n_qualified_61d(self, p0);
 RET_LABEL:;
 }
-/* method parser_prod#ASuperExpr#n_kwsuper= for (self: ASuperExpr, TKwsuper) */
-void parser_prod__ASuperExpr__n_kwsuper_61d(val* self, val* p0) {
-val* var_node /* var node: TKwsuper */;
-var_node = p0;
-self->attrs[COLOR_parser_nodes__ASuperExpr___n_kwsuper].val = var_node; /* _n_kwsuper on <self:ASuperExpr> */
-((void (*)(val*, val*))(var_node->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_node, self) /* parent= on <var_node:TKwsuper>*/;
-RET_LABEL:;
-}
-/* method parser_prod#ASuperExpr#n_kwsuper= for (self: Object, TKwsuper) */
-void VIRTUAL_parser_prod__ASuperExpr__n_kwsuper_61d(val* self, val* p0) {
-parser_prod__ASuperExpr__n_kwsuper_61d(self, p0);
-RET_LABEL:;
-}
-/* method parser_prod#ASuperExpr#n_args= for (self: ASuperExpr, AExprs) */
-void parser_prod__ASuperExpr__n_args_61d(val* self, val* p0) {
-val* var_node /* var node: AExprs */;
-var_node = p0;
-self->attrs[COLOR_parser_nodes__ASuperExpr___n_args].val = var_node; /* _n_args on <self:ASuperExpr> */
-((void (*)(val*, val*))(var_node->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_node, self) /* parent= on <var_node:AExprs>*/;
-RET_LABEL:;
-}
-/* method parser_prod#ASuperExpr#n_args= for (self: Object, AExprs) */
-void VIRTUAL_parser_prod__ASuperExpr__n_args_61d(val* self, val* p0) {
-parser_prod__ASuperExpr__n_args_61d(self, p0);
-RET_LABEL:;
-}
-/* method parser_prod#ASuperExpr#visit_all for (self: ASuperExpr, Visitor) */
-void parser_prod__ASuperExpr__visit_all(val* self, val* p0) {
-val* var_v /* var v: Visitor */;
-val* var /* : nullable AQualified */;
-val* var1 /* : null */;
-short int var2 /* : Bool */;
-val* var3 /* : nullable AQualified */;
-val* var4 /* : TKwsuper */;
-val* var5 /* : AExprs */;
-var_v = p0;
-var = self->attrs[COLOR_parser_nodes__ASuperExpr___n_qualified].val; /* _n_qualified on <self:ASuperExpr> */
-var1 = NULL;
-if (var == NULL) {
-var2 = 0; /* is null */
-} else {
-var2 = 1; /* arg is null and recv is not */
-}
-if (var2){
-var3 = self->attrs[COLOR_parser_nodes__ASuperExpr___n_qualified].val; /* _n_qualified on <self:ASuperExpr> */
-if (var3 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 7998);
-exit(1);
-}
-((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var3) /* enter_visit on <var_v:Visitor>*/;
-} else {
-}
-var4 = self->attrs[COLOR_parser_nodes__ASuperExpr___n_kwsuper].val; /* _n_kwsuper on <self:ASuperExpr> */
-if (var4 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwsuper", "src/parser/parser_prod.nit", 8000);
-exit(1);
-}
-((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var4) /* enter_visit on <var_v:Visitor>*/;
-var5 = self->attrs[COLOR_parser_nodes__ASuperExpr___n_args].val; /* _n_args on <self:ASuperExpr> */
-if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 8001);
-exit(1);
-}
-((void (*)(val*, val*))(var_v->class->vft[COLOR_parser_nodes__Visitor__enter_visit]))(var_v, var5) /* enter_visit on <var_v:Visitor>*/;
-RET_LABEL:;
-}
-/* method parser_prod#ASuperExpr#visit_all for (self: Object, Visitor) */
-void VIRTUAL_parser_prod__ASuperExpr__visit_all(val* self, val* p0) {
-parser_prod__ASuperExpr__visit_all(self, p0);
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#empty_init for (self: AInitExpr) */
-void parser_prod__AInitExpr__empty_init(val* self) {
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#empty_init for (self: Object) */
-void VIRTUAL_parser_prod__AInitExpr__empty_init(val* self) {
-parser_prod__AInitExpr__empty_init(self);
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#init_ainitexpr for (self: AInitExpr, nullable AExpr, nullable TKwinit, nullable AExprs) */
-void parser_prod__AInitExpr__init_ainitexpr(val* self, val* p0, val* p1, val* p2) {
-val* var_n_expr /* var n_expr: nullable AExpr */;
-val* var_n_kwinit /* var n_kwinit: nullable TKwinit */;
-val* var_n_args /* var n_args: nullable AExprs */;
-var_n_expr = p0;
-var_n_kwinit = p1;
-var_n_args = p2;
-((void (*)(val*))(self->class->vft[COLOR_parser_prod__AInitExpr__empty_init]))(self) /* empty_init on <self:AInitExpr>*/;
-if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 8014);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_n_expr; /* _n_expr on <self:AInitExpr> */
-if (var_n_expr == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 8015);
-exit(1);
-} else {
-((void (*)(val*, val*))(var_n_expr->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_expr, self) /* parent= on <var_n_expr:nullable AExpr>*/;
-}
-if (var_n_kwinit == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 8016);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AInitExpr___n_kwinit].val = var_n_kwinit; /* _n_kwinit on <self:AInitExpr> */
-if (var_n_kwinit == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 8017);
-exit(1);
-} else {
-((void (*)(val*, val*))(var_n_kwinit->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_kwinit, self) /* parent= on <var_n_kwinit:nullable TKwinit>*/;
-}
-if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Cast failed", "src/parser/parser_prod.nit", 8018);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AInitExpr___n_args].val = var_n_args; /* _n_args on <self:AInitExpr> */
-if (var_n_args == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Reciever is null", "src/parser/parser_prod.nit", 8019);
-exit(1);
-} else {
-((void (*)(val*, val*))(var_n_args->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_n_args, self) /* parent= on <var_n_args:nullable AExprs>*/;
-}
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#init_ainitexpr for (self: Object, nullable AExpr, nullable TKwinit, nullable AExprs) */
-void VIRTUAL_parser_prod__AInitExpr__init_ainitexpr(val* self, val* p0, val* p1, val* p2) {
-parser_prod__AInitExpr__init_ainitexpr(self, p0, p1, p2);
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#replace_child for (self: AInitExpr, ANode, nullable ANode) */
-void parser_prod__AInitExpr__replace_child(val* self, val* p0, val* p1) {
-val* var_old_child /* var old_child: ANode */;
-val* var_new_child /* var new_child: nullable ANode */;
-val* var /* : AExpr */;
-short int var1 /* : Bool */;
-val* var2 /* : null */;
-short int var3 /* : Bool */;
-short int var4 /* : Bool */;
-int cltype;
-int idtype;
-val* var5 /* : TKwinit */;
-short int var6 /* : Bool */;
-val* var7 /* : null */;
-short int var8 /* : Bool */;
-short int var9 /* : Bool */;
-int cltype10;
-int idtype11;
-val* var12 /* : AExprs */;
-short int var13 /* : Bool */;
-val* var14 /* : null */;
-short int var15 /* : Bool */;
-short int var16 /* : Bool */;
-int cltype17;
-int idtype18;
-var_old_child = p0;
-var_new_child = p1;
-var = self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val; /* _n_expr on <self:AInitExpr> */
-if (var == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_expr", "src/parser/parser_prod.nit", 8024);
-exit(1);
-}
-var1 = ((short int (*)(val*, val*))(var->class->vft[COLOR_kernel__Object___61d_61d]))(var, var_old_child) /* == on <var:AExpr>*/;
-if (var1){
-var2 = NULL;
-if (var_new_child == NULL) {
-var3 = 0; /* is null */
-} else {
-var3 = 1; /* arg is null and recv is not */
-}
-if (var3){
-((void (*)(val*, val*))(var_new_child->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_new_child, self) /* parent= on <var_new_child:nullable ANode(ANode)>*/;
-/* <var_new_child:nullable ANode(ANode)> isa AExpr */
-cltype = type_parser_nodes__AExpr.color;
-idtype = type_parser_nodes__AExpr.id;
-if(cltype >= var_new_child->type->table_size) {
-var4 = 0;
-} else {
-var4 = var_new_child->type->type_table[cltype] == idtype;
-}
-if (!var4) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 8027);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_new_child; /* _n_expr on <self:AInitExpr> */
-} else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 8030);
-exit(1);
-}
-goto RET_LABEL;
-} else {
-}
-var5 = self->attrs[COLOR_parser_nodes__AInitExpr___n_kwinit].val; /* _n_kwinit on <self:AInitExpr> */
-if (var5 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_kwinit", "src/parser/parser_prod.nit", 8034);
-exit(1);
-}
-var6 = ((short int (*)(val*, val*))(var5->class->vft[COLOR_kernel__Object___61d_61d]))(var5, var_old_child) /* == on <var5:TKwinit>*/;
-if (var6){
-var7 = NULL;
-if (var_new_child == NULL) {
-var8 = 0; /* is null */
-} else {
-var8 = 1; /* arg is null and recv is not */
-}
-if (var8){
-((void (*)(val*, val*))(var_new_child->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_new_child, self) /* parent= on <var_new_child:nullable ANode(ANode)>*/;
-/* <var_new_child:nullable ANode(ANode)> isa TKwinit */
-cltype10 = type_parser_nodes__TKwinit.color;
-idtype11 = type_parser_nodes__TKwinit.id;
-if(cltype10 >= var_new_child->type->table_size) {
-var9 = 0;
-} else {
-var9 = var_new_child->type->type_table[cltype10] == idtype11;
-}
-if (!var9) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 8037);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AInitExpr___n_kwinit].val = var_new_child; /* _n_kwinit on <self:AInitExpr> */
-} else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 8040);
-exit(1);
-}
-goto RET_LABEL;
-} else {
-}
-var12 = self->attrs[COLOR_parser_nodes__AInitExpr___n_args].val; /* _n_args on <self:AInitExpr> */
-if (var12 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _n_args", "src/parser/parser_prod.nit", 8044);
-exit(1);
-}
-var13 = ((short int (*)(val*, val*))(var12->class->vft[COLOR_kernel__Object___61d_61d]))(var12, var_old_child) /* == on <var12:AExprs>*/;
-if (var13){
-var14 = NULL;
-if (var_new_child == NULL) {
-var15 = 0; /* is null */
-} else {
-var15 = 1; /* arg is null and recv is not */
-}
-if (var15){
-((void (*)(val*, val*))(var_new_child->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_new_child, self) /* parent= on <var_new_child:nullable ANode(ANode)>*/;
-/* <var_new_child:nullable ANode(ANode)> isa AExprs */
-cltype17 = type_parser_nodes__AExprs.color;
-idtype18 = type_parser_nodes__AExprs.id;
-if(cltype17 >= var_new_child->type->table_size) {
-var16 = 0;
-} else {
-var16 = var_new_child->type->type_table[cltype17] == idtype18;
-}
-if (!var16) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Assert failed", "src/parser/parser_prod.nit", 8047);
-exit(1);
-}
-self->attrs[COLOR_parser_nodes__AInitExpr___n_args].val = var_new_child; /* _n_args on <self:AInitExpr> */
-} else {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Aborted", "src/parser/parser_prod.nit", 8050);
-exit(1);
-}
-goto RET_LABEL;
-} else {
-}
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#replace_child for (self: Object, ANode, nullable ANode) */
-void VIRTUAL_parser_prod__AInitExpr__replace_child(val* self, val* p0, val* p1) {
-parser_prod__AInitExpr__replace_child(self, p0, p1);
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#n_expr= for (self: AInitExpr, AExpr) */
-void parser_prod__AInitExpr__n_expr_61d(val* self, val* p0) {
-val* var_node /* var node: AExpr */;
-var_node = p0;
-self->attrs[COLOR_parser_nodes__ASendExpr___n_expr].val = var_node; /* _n_expr on <self:AInitExpr> */
-((void (*)(val*, val*))(var_node->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_node, self) /* parent= on <var_node:AExpr>*/;
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#n_expr= for (self: Object, AExpr) */
-void VIRTUAL_parser_prod__AInitExpr__n_expr_61d(val* self, val* p0) {
-parser_prod__AInitExpr__n_expr_61d(self, p0);
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#n_kwinit= for (self: AInitExpr, TKwinit) */
-void parser_prod__AInitExpr__n_kwinit_61d(val* self, val* p0) {
-val* var_node /* var node: TKwinit */;
-var_node = p0;
-self->attrs[COLOR_parser_nodes__AInitExpr___n_kwinit].val = var_node; /* _n_kwinit on <self:AInitExpr> */
-((void (*)(val*, val*))(var_node->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_node, self) /* parent= on <var_node:TKwinit>*/;
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#n_kwinit= for (self: Object, TKwinit) */
-void VIRTUAL_parser_prod__AInitExpr__n_kwinit_61d(val* self, val* p0) {
-parser_prod__AInitExpr__n_kwinit_61d(self, p0);
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#n_args= for (self: AInitExpr, AExprs) */
-void parser_prod__AInitExpr__n_args_61d(val* self, val* p0) {
-val* var_node /* var node: AExprs */;
-var_node = p0;
-self->attrs[COLOR_parser_nodes__AInitExpr___n_args].val = var_node; /* _n_args on <self:AInitExpr> */
-((void (*)(val*, val*))(var_node->class->vft[COLOR_parser_nodes__ANode__parent_61d]))(var_node, self) /* parent= on <var_node:AExprs>*/;
-RET_LABEL:;
-}
-/* method parser_prod#AInitExpr#n_args= for (self: Object, AExprs) */
-void VIRTUAL_parser_prod__AInitExpr__n_args_61d(val* self, val* p0) {
-parser_prod__AInitExpr__n_args_61d(self, p0);
-RET_LABEL:;
-}