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

diff --git a/c_src/abstract_collection.sep.1.c b/c_src/abstract_collection.sep.1.c
index b4ddfd9..60f5245 100644
--- a/c_src/abstract_collection.sep.1.c
+++ b/c_src/abstract_collection.sep.1.c
@@ -1,38 +1,24 @@
 #include "abstract_collection.sep.0.h"
-/* method abstract_collection#Collection#iterator for (self: Collection[nullable Object]): Iterator[nullable Object] */
-val* abstract_collection__Collection__iterator(val* self) {
-val* var /* : Iterator[nullable Object] */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "iterator", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 54);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Collection#iterator for (self: Object): Iterator[nullable Object] */
-val* VIRTUAL_abstract_collection__Collection__iterator(val* self) {
-val* var /* : Iterator[nullable Object] */;
-val* var1 /* : Iterator[nullable Object] */;
-var1 = abstract_collection__Collection__iterator(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
 /* method abstract_collection#Collection#is_empty for (self: Collection[nullable Object]): Bool */
 short int abstract_collection__Collection__is_empty(val* self) {
 short int var /* : Bool */;
 long var1 /* : Int */;
 long var2 /* : Int */;
 short int var3 /* : Bool */;
-short int var5 /* : Bool */;
+short int var4 /* : Bool */;
+short int var6 /* : Bool */;
+{
 var1 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Collection[nullable Object]>*/;
+}
 var2 = 0;
-{ /* Inline kernel#Int#== (var1,var2) */
-var5 = var1 == var2;
-var3 = var5;
-goto RET_LABEL4;
-RET_LABEL4:(void)0;
+{
+{ /* Inline kernel#Int#== (var1,var2) on <var1:Int> */
+var6 = var1 == var2;
+var4 = var6;
+goto RET_LABEL5;
+RET_LABEL5:(void)0;
+}
+var3 = var4;
 }
 var = var3;
 goto RET_LABEL;
@@ -53,33 +39,67 @@ long abstract_collection__Collection__length(val* self) {
 long var /* : Int */;
 long var1 /* : Int */;
 long var_nb /* var nb: Int */;
+val* var_ /* var : Collection[nullable Object] */;
 val* var2 /* : Iterator[nullable Object] */;
-short int var3 /* : Bool */;
-val* var4 /* : nullable Object */;
+val* var_3 /* var : Iterator[nullable Object] */;
+short int var4 /* : Bool */;
+val* var5 /* : nullable Object */;
 val* var_i /* var i: nullable Object */;
-long var5 /* : Int */;
 long var6 /* : Int */;
-long var8 /* : Int */;
+long var7 /* : Int */;
+short int var9 /* : Bool */;
+int cltype;
+int idtype;
+const char* var_class_name;
+long var10 /* : Int */;
 var1 = 0;
 var_nb = var1;
-var2 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:Collection[nullable Object]>*/;
+var_ = self;
+{
+var2 = ((val* (*)(val*))(var_->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[nullable Object]>*/;
+}
+var_3 = var2;
 for(;;) {
-var3 = ((short int (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var2) /* is_ok on <var2:Iterator[nullable Object]>*/;
-if(!var3) break;
-var4 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__item]))(var2) /* item on <var2:Iterator[nullable Object]>*/;
-var_i = var4;
-var5 = 1;
-{ /* Inline kernel#Int#+ (var_nb,var5) */
-var8 = var_nb + var5;
-var6 = var8;
-goto RET_LABEL7;
-RET_LABEL7:(void)0;
+{
+var4 = ((short int (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_3) /* is_ok on <var_3:Iterator[nullable Object]>*/;
+}
+if (var4){
+{
+var5 = ((val* (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__item]))(var_3) /* item on <var_3:Iterator[nullable Object]>*/;
+}
+var_i = var5;
+var6 = 1;
+{
+{ /* Inline kernel#Int#+ (var_nb,var6) on <var_nb:Int> */
+/* Covariant cast for argument 0 (i) <var6:Int> isa OTHER */
+/* <var6:Int> isa OTHER */
+var9 = 1; /* easy <var6:Int> isa OTHER*/
+if (unlikely(!var9)) {
+var_class_name = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var10 = var_nb + var6;
+var7 = var10;
+goto RET_LABEL8;
+RET_LABEL8:(void)0;
+}
+}
+var_nb = var7;
+{
+((void (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__next]))(var_3) /* next on <var_3:Iterator[nullable Object]>*/;
+}
+} else {
+goto BREAK_label;
 }
-var_nb = var6;
-CONTINUE_label: (void)0;
-((void (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__next]))(var2) /* next on <var2:Iterator[nullable Object]>*/;
 }
 BREAK_label: (void)0;
+{
+{ /* Inline abstract_collection#Iterator#finish (var_3) on <var_3:Iterator[nullable Object]> */
+RET_LABEL11:(void)0;
+}
+}
 var = var_nb;
 goto RET_LABEL;
 RET_LABEL:;
@@ -104,15 +124,18 @@ const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
 val* var_item /* var item: nullable Object */;
+val* var_ /* var : Collection[nullable Object] */;
 val* var2 /* : Iterator[nullable Object] */;
-short int var3 /* : Bool */;
-val* var4 /* : nullable Object */;
+val* var_3 /* var : Iterator[nullable Object] */;
+short int var4 /* : Bool */;
+val* var5 /* : nullable Object */;
 val* var_i /* var i: nullable Object */;
-short int var5 /* : Bool */;
 short int var6 /* : Bool */;
 short int var7 /* : Bool */;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa Collection#0 */
-/* <p0:nullable Object> isa Collection#0 */
+short int var8 /* : Bool */;
+short int var10 /* : Bool */;
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -126,204 +149,63 @@ var1 = 0;
 var1 = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var1) {
+if (unlikely(!var1)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 75);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 76);
+show_backtrace(1);
 }
 var_item = p0;
-var2 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:Collection[nullable Object]>*/;
-for(;;) {
-var3 = ((short int (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var2) /* is_ok on <var2:Iterator[nullable Object]>*/;
-if(!var3) break;
-var4 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__item]))(var2) /* item on <var2:Iterator[nullable Object]>*/;
-var_i = var4;
-if (var_i == NULL) {
-var5 = (var_item == NULL);
-} else {
-var5 = ((short int (*)(val*, val*))(var_i->class->vft[COLOR_kernel__Object___61d_61d]))(var_i, var_item) /* == on <var_i:nullable Object>*/;
-}
-if (var5){
-var6 = 1;
-var = var6;
-goto RET_LABEL;
-} else {
-}
-CONTINUE_label: (void)0;
-((void (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__next]))(var2) /* next on <var2:Iterator[nullable Object]>*/;
-}
-BREAK_label: (void)0;
-var7 = 0;
-var = var7;
-goto RET_LABEL;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Collection#has for (self: Object, nullable Object): Bool */
-short int VIRTUAL_abstract_collection__Collection__has(val* self, val* p0) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-var1 = abstract_collection__Collection__has(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Collection#has_only for (self: Collection[nullable Object], nullable Object): Bool */
-short int abstract_collection__Collection__has_only(val* self, val* p0) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-short int is_nullable;
-const char* var_class_name;
-val* var_item /* var item: nullable Object */;
-val* var2 /* : Iterator[nullable Object] */;
-short int var3 /* : Bool */;
-val* var4 /* : nullable Object */;
-val* var_i /* var i: nullable Object */;
-short int var5 /* : Bool */;
-short int var6 /* : Bool */;
-short int var7 /* : Bool */;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa Collection#0 */
-/* <p0:nullable Object> isa Collection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-is_nullable = type_struct->is_nullable;
-if(p0 == NULL) {
-var1 = is_nullable;
-} else {
-if(cltype >= p0->type->table_size) {
-var1 = 0;
-} else {
-var1 = p0->type->type_table[cltype] == idtype;
+var_ = self;
+{
+var2 = ((val* (*)(val*))(var_->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[nullable Object]>*/;
 }
+var_3 = var2;
+for(;;) {
+{
+var4 = ((short int (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_3) /* is_ok on <var_3:Iterator[nullable Object]>*/;
 }
-if (!var1) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 88);
-exit(1);
+if (var4){
+{
+var5 = ((val* (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__item]))(var_3) /* item on <var_3:Iterator[nullable Object]>*/;
 }
-var_item = p0;
-var2 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:Collection[nullable Object]>*/;
-for(;;) {
-var3 = ((short int (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var2) /* is_ok on <var2:Iterator[nullable Object]>*/;
-if(!var3) break;
-var4 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__item]))(var2) /* item on <var2:Iterator[nullable Object]>*/;
-var_i = var4;
+var_i = var5;
 if (var_i == NULL) {
-var5 = (var_item != NULL);
+var6 = (var_item == NULL);
 } else {
-var5 = ((short int (*)(val*, val*))(var_i->class->vft[COLOR_kernel__Object___33d_61d]))(var_i, var_item) /* != on <var_i:nullable Object>*/;
+var7 = ((short int (*)(val*, val*))(var_i->class->vft[COLOR_kernel__Object___61d_61d]))(var_i, var_item) /* == on <var_i:nullable Object>*/;
+var6 = var7;
 }
-if (var5){
-var6 = 0;
-var = var6;
+if (var6){
+var8 = 1;
+var = var8;
 goto RET_LABEL;
 } else {
 }
-CONTINUE_label: (void)0;
-((void (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__next]))(var2) /* next on <var2:Iterator[nullable Object]>*/;
-}
-BREAK_label: (void)0;
-var7 = 1;
-var = var7;
-goto RET_LABEL;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Collection#has_only for (self: Object, nullable Object): Bool */
-short int VIRTUAL_abstract_collection__Collection__has_only(val* self, val* p0) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-var1 = abstract_collection__Collection__has_only(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
+{
+((void (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__next]))(var_3) /* next on <var_3:Iterator[nullable Object]>*/;
 }
-/* method abstract_collection#Collection#count for (self: Collection[nullable Object], nullable Object): Int */
-long abstract_collection__Collection__count(val* self, val* p0) {
-long var /* : Int */;
-short int var1 /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-short int is_nullable;
-const char* var_class_name;
-val* var_item /* var item: nullable Object */;
-long var2 /* : Int */;
-long var_nb /* var nb: Int */;
-val* var3 /* : Iterator[nullable Object] */;
-short int var4 /* : Bool */;
-val* var5 /* : nullable Object */;
-val* var_i /* var i: nullable Object */;
-short int var6 /* : Bool */;
-long var7 /* : Int */;
-long var8 /* : Int */;
-long var10 /* : Int */;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa Collection#0 */
-/* <p0:nullable Object> isa Collection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-is_nullable = type_struct->is_nullable;
-if(p0 == NULL) {
-var1 = is_nullable;
-} else {
-if(cltype >= p0->type->table_size) {
-var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
-}
-}
-if (!var1) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 105);
-exit(1);
+goto BREAK_label;
 }
-var_item = p0;
-var2 = 0;
-var_nb = var2;
-var3 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:Collection[nullable Object]>*/;
-for(;;) {
-var4 = ((short int (*)(val*))(var3->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var3) /* is_ok on <var3:Iterator[nullable Object]>*/;
-if(!var4) break;
-var5 = ((val* (*)(val*))(var3->class->vft[COLOR_abstract_collection__Iterator__item]))(var3) /* item on <var3:Iterator[nullable Object]>*/;
-var_i = var5;
-if (var_i == NULL) {
-var6 = (var_item == NULL);
-} else {
-var6 = ((short int (*)(val*, val*))(var_i->class->vft[COLOR_kernel__Object___61d_61d]))(var_i, var_item) /* == on <var_i:nullable Object>*/;
 }
-if (var6){
-var7 = 1;
-{ /* Inline kernel#Int#+ (var_nb,var7) */
-var10 = var_nb + var7;
-var8 = var10;
-goto RET_LABEL9;
+BREAK_label: (void)0;
+{
+{ /* Inline abstract_collection#Iterator#finish (var_3) on <var_3:Iterator[nullable Object]> */
 RET_LABEL9:(void)0;
 }
-var_nb = var8;
-} else {
-}
-CONTINUE_label: (void)0;
-((void (*)(val*))(var3->class->vft[COLOR_abstract_collection__Iterator__next]))(var3) /* next on <var3:Iterator[nullable Object]>*/;
 }
-BREAK_label: (void)0;
-var = var_nb;
+var10 = 0;
+var = var10;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Collection#count for (self: Object, nullable Object): Int */
-long VIRTUAL_abstract_collection__Collection__count(val* self, val* p0) {
-long var /* : Int */;
-long var1 /* : Int */;
-var1 = abstract_collection__Collection__count(self, p0);
+/* method abstract_collection#Collection#has for (self: Object, nullable Object): Bool */
+short int VIRTUAL_abstract_collection__Collection__has(val* self, val* p0) {
+short int var /* : Bool */;
+short int var1 /* : Bool */;
+var1 = abstract_collection__Collection__has(self, p0);
 var = var1;
 RET_LABEL:;
 return var;
@@ -341,30 +223,38 @@ const char* var_class_name;
 short int var6 /* : Bool */;
 val* var7 /* : Iterator[nullable Object] */;
 val* var8 /* : nullable Object */;
+{
 var1 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Collection[nullable Object]>*/;
+}
 var2 = 0;
-{ /* Inline kernel#Int#> (var1,var2) */
+{
+{ /* Inline kernel#Int#> (var1,var2) on <var1:Int> */
 /* Covariant cast for argument 0 (i) <var2:Int> isa OTHER */
 /* <var2:Int> isa OTHER */
 var5 = 1; /* easy <var2:Int> isa OTHER*/
-if (!var5) {
+if (unlikely(!var5)) {
 var_class_name = type_kernel__Int.name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/kernel.nit", 263);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 373);
+show_backtrace(1);
 }
 var6 = var1 > var2;
 var3 = var6;
 goto RET_LABEL4;
 RET_LABEL4:(void)0;
 }
-if (!var3) {
-fprintf(stderr, "Runtime error: %s", "Assert failed");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 121);
-exit(1);
 }
+if (unlikely(!var3)) {
+PRINT_ERROR("Runtime error: %s", "Assert failed");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 122);
+show_backtrace(1);
+}
+{
 var7 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:Collection[nullable Object]>*/;
+}
+{
 var8 = ((val* (*)(val*))(var7->class->vft[COLOR_abstract_collection__Iterator__item]))(var7) /* item on <var7:Iterator[nullable Object]>*/;
+}
 var = var8;
 goto RET_LABEL;
 RET_LABEL:;
@@ -388,16 +278,18 @@ int idtype;
 const struct type* type_struct;
 const char* var_class_name;
 val* var_other /* var other: Collection[nullable Object] */;
+val* var_ /* var : Collection[nullable Object] */;
 val* var2 /* : Iterator[nullable Object] */;
-short int var3 /* : Bool */;
-val* var4 /* : nullable Object */;
+val* var_3 /* var : Iterator[nullable Object] */;
+short int var4 /* : Bool */;
+val* var5 /* : nullable Object */;
 val* var_x /* var x: nullable Object */;
-short int var5 /* : Bool */;
 short int var6 /* : Bool */;
 short int var7 /* : Bool */;
 short int var8 /* : Bool */;
-/* Covariant cast for argument 0 (other) <p0:Collection[nullable Object]> isa Collection[Collection#0] */
-/* <p0:Collection[nullable Object]> isa Collection[Collection#0] */
+short int var10 /* : Bool */;
+/* Covariant cast for argument 0 (other) <p0:Collection[nullable Object]> isa Collection[E] */
+/* <p0:Collection[nullable Object]> isa Collection[E] */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collectionabstract_collection__Collection_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -406,33 +298,52 @@ var1 = 0;
 } else {
 var1 = p0->type->type_table[cltype] == idtype;
 }
-if (!var1) {
+if (unlikely(!var1)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[Collection#0]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 125);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 126);
+show_backtrace(1);
 }
 var_other = p0;
-var2 = ((val* (*)(val*))(var_other->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_other) /* iterator on <var_other:Collection[nullable Object]>*/;
+var_ = var_other;
+{
+var2 = ((val* (*)(val*))(var_->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[nullable Object]>*/;
+}
+var_3 = var2;
 for(;;) {
-var3 = ((short int (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var2) /* is_ok on <var2:Iterator[nullable Object]>*/;
-if(!var3) break;
-var4 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__item]))(var2) /* item on <var2:Iterator[nullable Object]>*/;
-var_x = var4;
-var5 = ((short int (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Collection__has]))(self, var_x) /* has on <self:Collection[nullable Object]>*/;
-var6 = !var5;
-if (var6){
-var7 = 0;
-var = var7;
+{
+var4 = ((short int (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_3) /* is_ok on <var_3:Iterator[nullable Object]>*/;
+}
+if (var4){
+{
+var5 = ((val* (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__item]))(var_3) /* item on <var_3:Iterator[nullable Object]>*/;
+}
+var_x = var5;
+{
+var6 = ((short int (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Collection__has]))(self, var_x) /* has on <self:Collection[nullable Object]>*/;
+}
+var7 = !var6;
+if (var7){
+var8 = 0;
+var = var8;
 goto RET_LABEL;
 } else {
 }
-CONTINUE_label: (void)0;
-((void (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__next]))(var2) /* next on <var2:Iterator[nullable Object]>*/;
+{
+((void (*)(val*))(var_3->class->vft[COLOR_abstract_collection__Iterator__next]))(var_3) /* next on <var_3:Iterator[nullable Object]>*/;
+}
+} else {
+goto BREAK_label;
+}
 }
 BREAK_label: (void)0;
-var8 = 1;
-var = var8;
+{
+{ /* Inline abstract_collection#Iterator#finish (var_3) on <var_3:Iterator[nullable Object]> */
+RET_LABEL9:(void)0;
+}
+}
+var10 = 1;
+var = var10;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -446,65 +357,46 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Iterator#item for (self: Iterator[nullable Object]): nullable Object */
-val* abstract_collection__Iterator__item(val* self) {
-val* var /* : nullable Object */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "item", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 141);
-exit(1);
+/* method abstract_collection#Iterator#iterator for (self: Iterator[nullable Object]): Iterator[nullable Object] */
+val* abstract_collection__Iterator__iterator(val* self) {
+val* var /* : Iterator[nullable Object] */;
+var = self;
+goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Iterator#item for (self: Object): nullable Object */
-val* VIRTUAL_abstract_collection__Iterator__item(val* self) {
-val* var /* : nullable Object */;
-val* var1 /* : nullable Object */;
-var1 = abstract_collection__Iterator__item(self);
+/* method abstract_collection#Iterator#iterator for (self: Object): Iterator[nullable Object] */
+val* VIRTUAL_abstract_collection__Iterator__iterator(val* self) {
+val* var /* : Iterator[nullable Object] */;
+val* var1 /* : Iterator[nullable Object] */;
+var1 = abstract_collection__Iterator__iterator(self);
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Iterator#next for (self: Iterator[nullable Object]) */
-void abstract_collection__Iterator__next(val* self) {
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "next", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 145);
-exit(1);
-RET_LABEL:;
-}
-/* method abstract_collection#Iterator#next for (self: Object) */
-void VIRTUAL_abstract_collection__Iterator__next(val* self) {
-abstract_collection__Iterator__next(self);
+/* method abstract_collection#Iterator#finish for (self: Iterator[nullable Object]) */
+void abstract_collection__Iterator__finish(val* self) {
 RET_LABEL:;
 }
-/* method abstract_collection#Iterator#is_ok for (self: Iterator[nullable Object]): Bool */
-short int abstract_collection__Iterator__is_ok(val* self) {
-short int var /* : Bool */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "is_ok", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 149);
-exit(1);
-RET_LABEL:;
-return var;
+/* method abstract_collection#Iterator#finish for (self: Object) */
+void VIRTUAL_abstract_collection__Iterator__finish(val* self) {
+{ /* Inline abstract_collection#Iterator#finish (self) on <self:Object(Iterator[nullable Object])> */
+RET_LABEL1:(void)0;
 }
-/* method abstract_collection#Iterator#is_ok for (self: Object): Bool */
-short int VIRTUAL_abstract_collection__Iterator__is_ok(val* self) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-var1 = abstract_collection__Iterator__is_ok(self);
-var = var1;
 RET_LABEL:;
-return var;
 }
 /* method abstract_collection#Container#first for (self: Container[nullable Object]): nullable Object */
 val* abstract_collection__Container__first(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = self->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <self:Container[nullable Object]> */
+val* var3 /* : nullable Object */;
+{
+{ /* Inline abstract_collection#Container#item (self) on <self:Container[nullable Object]> */
+var3 = self->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <self:Container[nullable Object]> */
+var1 = var3;
+RET_LABEL2:(void)0;
+}
+}
 var = var1;
 goto RET_LABEL;
 RET_LABEL:;
@@ -568,9 +460,11 @@ short int is_nullable;
 const char* var_class_name;
 val* var_an_item /* var an_item: nullable Object */;
 val* var2 /* : nullable Object */;
-short int var3 /* : Bool */;
-/* Covariant cast for argument 0 (an_item) <p0:nullable Object> isa Collection#0 */
-/* <p0:nullable Object> isa Collection#0 */
+val* var4 /* : nullable Object */;
+short int var5 /* : Bool */;
+short int var6 /* : Bool */;
+/* Covariant cast for argument 0 (an_item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -584,20 +478,27 @@ var1 = 0;
 var1 = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var1) {
+if (unlikely(!var1)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 163);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 182);
+show_backtrace(1);
 }
 var_an_item = p0;
-var2 = self->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <self:Container[nullable Object]> */
+{
+{ /* Inline abstract_collection#Container#item (self) on <self:Container[nullable Object]> */
+var4 = self->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <self:Container[nullable Object]> */
+var2 = var4;
+RET_LABEL3:(void)0;
+}
+}
 if (var2 == NULL) {
-var3 = (var_an_item == NULL);
+var5 = (var_an_item == NULL);
 } else {
-var3 = ((short int (*)(val*, val*))(var2->class->vft[COLOR_kernel__Object___61d_61d]))(var2, var_an_item) /* == on <var2:nullable Object>*/;
+var6 = ((short int (*)(val*, val*))(var2->class->vft[COLOR_kernel__Object___61d_61d]))(var2, var_an_item) /* == on <var2:nullable Object>*/;
+var5 = var6;
 }
-var = var3;
+var = var5;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -611,130 +512,14 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Container#has_only for (self: Container[nullable Object], nullable Object): Bool */
-short int abstract_collection__Container__has_only(val* self, val* p0) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-short int is_nullable;
-const char* var_class_name;
-val* var_an_item /* var an_item: nullable Object */;
-val* var2 /* : nullable Object */;
-short int var3 /* : Bool */;
-/* Covariant cast for argument 0 (an_item) <p0:nullable Object> isa Collection#0 */
-/* <p0:nullable Object> isa Collection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-is_nullable = type_struct->is_nullable;
-if(p0 == NULL) {
-var1 = is_nullable;
-} else {
-if(cltype >= p0->type->table_size) {
-var1 = 0;
-} else {
-var1 = p0->type->type_table[cltype] == idtype;
-}
-}
-if (!var1) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 165);
-exit(1);
-}
-var_an_item = p0;
-var2 = self->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <self:Container[nullable Object]> */
-if (var2 == NULL) {
-var3 = (var_an_item == NULL);
-} else {
-var3 = ((short int (*)(val*, val*))(var2->class->vft[COLOR_kernel__Object___61d_61d]))(var2, var_an_item) /* == on <var2:nullable Object>*/;
-}
-var = var3;
-goto RET_LABEL;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Container#has_only for (self: Object, nullable Object): Bool */
-short int VIRTUAL_abstract_collection__Container__has_only(val* self, val* p0) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-var1 = abstract_collection__Container__has_only(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Container#count for (self: Container[nullable Object], nullable Object): Int */
-long abstract_collection__Container__count(val* self, val* p0) {
-long var /* : Int */;
-short int var1 /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-short int is_nullable;
-const char* var_class_name;
-val* var_an_item /* var an_item: nullable Object */;
-val* var2 /* : nullable Object */;
-short int var3 /* : Bool */;
-long var4 /* : Int */;
-long var5 /* : Int */;
-/* Covariant cast for argument 0 (an_item) <p0:nullable Object> isa Collection#0 */
-/* <p0:nullable Object> isa Collection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-is_nullable = type_struct->is_nullable;
-if(p0 == NULL) {
-var1 = is_nullable;
-} else {
-if(cltype >= p0->type->table_size) {
-var1 = 0;
-} else {
-var1 = p0->type->type_table[cltype] == idtype;
-}
-}
-if (!var1) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 167);
-exit(1);
-}
-var_an_item = p0;
-var2 = self->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <self:Container[nullable Object]> */
-if (var2 == NULL) {
-var3 = (var_an_item == NULL);
-} else {
-var3 = ((short int (*)(val*, val*))(var2->class->vft[COLOR_kernel__Object___61d_61d]))(var2, var_an_item) /* == on <var2:nullable Object>*/;
-}
-if (var3){
-var4 = 1;
-var = var4;
-goto RET_LABEL;
-} else {
-var5 = 0;
-var = var5;
-goto RET_LABEL;
-}
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Container#count for (self: Object, nullable Object): Int */
-long VIRTUAL_abstract_collection__Container__count(val* self, val* p0) {
-long var /* : Int */;
-long var1 /* : Int */;
-var1 = abstract_collection__Container__count(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
-}
 /* method abstract_collection#Container#iterator for (self: Container[nullable Object]): Iterator[nullable Object] */
 val* abstract_collection__Container__iterator(val* self) {
 val* var /* : Iterator[nullable Object] */;
 val* var1 /* : ContainerIterator[nullable Object] */;
 var1 = NEW_abstract_collection__ContainerIterator(self->type->resolution_table->types[COLOR_abstract_collection__ContainerIteratorabstract_collection__Container_FT0]);
-((void (*)(val*, val*))(var1->class->vft[COLOR_abstract_collection__ContainerIterator__init]))(var1, self) /* init on <var1:ContainerIterator[nullable Object]>*/;
-CHECK_NEW_abstract_collection__ContainerIterator(var1);
+{
+abstract_collection__ContainerIterator__init(var1, self); /* Direct call abstract_collection#ContainerIterator#init on <var1:ContainerIterator[nullable Object]>*/
+}
 var = var1;
 goto RET_LABEL;
 RET_LABEL:;
@@ -758,8 +543,14 @@ const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
 val* var_e /* var e: nullable Object */;
-/* Covariant cast for argument 0 (e) <p0:nullable Object> isa Container#0 */
-/* <p0:nullable Object> isa Container#0 */
+short int var2 /* : Bool */;
+int cltype3;
+int idtype4;
+const struct type* type_struct5;
+short int is_nullable6;
+const char* var_class_name7;
+/* Covariant cast for argument 0 (e) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Container_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -773,19 +564,45 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Container#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 178);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 197);
+show_backtrace(1);
 }
 var_e = p0;
+{
+{ /* Inline abstract_collection#Container#item= (self,var_e) on <self:Container[nullable Object]> */
+/* Covariant cast for argument 0 (item) <var_e:nullable Object> isa E */
+/* <var_e:nullable Object> isa E */
+type_struct5 = self->type->resolution_table->types[COLOR_abstract_collection__Container_FT0];
+cltype3 = type_struct5->color;
+idtype4 = type_struct5->id;
+is_nullable6 = type_struct5->is_nullable;
+if(var_e == NULL) {
+var2 = is_nullable6;
+} else {
+if(cltype3 >= var_e->type->table_size) {
+var2 = 0;
+} else {
+var2 = var_e->type->type_table[cltype3] == idtype4;
+}
+}
+if (unlikely(!var2)) {
+var_class_name7 = var_e == NULL ? "null" : var_e->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name7);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 200);
+show_backtrace(1);
+}
 self->attrs[COLOR_abstract_collection__Container___item].val = var_e; /* _item on <self:Container[nullable Object]> */
+RET_LABEL1:(void)0;
+}
+}
 RET_LABEL:;
 }
 /* method abstract_collection#Container#init for (self: Object, nullable Object) */
 void VIRTUAL_abstract_collection__Container__init(val* self, val* p0) {
-abstract_collection__Container__init(self, p0);
+abstract_collection__Container__init(self, p0); /* Direct call abstract_collection#Container#init on <self:Object(Container[nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#Container#item for (self: Container[nullable Object]): nullable Object */
@@ -801,7 +618,12 @@ return var;
 val* VIRTUAL_abstract_collection__Container__item(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = abstract_collection__Container__item(self);
+val* var3 /* : nullable Object */;
+{ /* Inline abstract_collection#Container#item (self) on <self:Object(Container[nullable Object])> */
+var3 = self->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <self:Object(Container[nullable Object])> */
+var1 = var3;
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
 return var;
@@ -814,8 +636,8 @@ int idtype;
 const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa Container#0 */
-/* <p0:nullable Object> isa Container#0 */
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Container_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -829,18 +651,48 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Container#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 181);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 200);
+show_backtrace(1);
 }
 self->attrs[COLOR_abstract_collection__Container___item].val = p0; /* _item on <self:Container[nullable Object]> */
 RET_LABEL:;
 }
 /* method abstract_collection#Container#item= for (self: Object, nullable Object) */
 void VIRTUAL_abstract_collection__Container__item_61d(val* self, val* p0) {
-abstract_collection__Container__item_61d(self, p0);
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+short int is_nullable;
+const char* var_class_name;
+{ /* Inline abstract_collection#Container#item= (self,p0) on <self:Object(Container[nullable Object])> */
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Container_FT0];
+cltype = type_struct->color;
+idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var = is_nullable;
+} else {
+if(cltype >= p0->type->table_size) {
+var = 0;
+} else {
+var = p0->type->type_table[cltype] == idtype;
+}
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 200);
+show_backtrace(1);
+}
+self->attrs[COLOR_abstract_collection__Container___item].val = p0; /* _item on <self:Object(Container[nullable Object])> */
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#ContainerIterator#item for (self: ContainerIterator[nullable Object]): nullable Object */
@@ -848,13 +700,20 @@ val* abstract_collection__ContainerIterator__item(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : Container[nullable Object] */;
 val* var2 /* : nullable Object */;
+val* var4 /* : nullable Object */;
 var1 = self->attrs[COLOR_abstract_collection__ContainerIterator___container].val; /* _container on <self:ContainerIterator[nullable Object]> */
-if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _container");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 188);
-exit(1);
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _container");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 207);
+show_backtrace(1);
+}
+{
+{ /* Inline abstract_collection#Container#item (var1) on <var1:Container[nullable Object]> */
+var4 = var1->attrs[COLOR_abstract_collection__Container___item].val; /* _item on <var1:Container[nullable Object]> */
+var2 = var4;
+RET_LABEL3:(void)0;
+}
 }
-var2 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__Container__item]))(var1) /* item on <var1:Container[nullable Object]>*/;
 var = var2;
 goto RET_LABEL;
 RET_LABEL:;
@@ -873,12 +732,17 @@ return var;
 void abstract_collection__ContainerIterator__next(val* self) {
 short int var /* : Bool */;
 var = 0;
+{
+{ /* Inline abstract_collection#ContainerIterator#is_ok= (self,var) on <self:ContainerIterator[nullable Object]> */
 self->attrs[COLOR_abstract_collection__ContainerIterator___is_ok].s = var; /* _is_ok on <self:ContainerIterator[nullable Object]> */
+RET_LABEL1:(void)0;
+}
+}
 RET_LABEL:;
 }
 /* method abstract_collection#ContainerIterator#next for (self: Object) */
 void VIRTUAL_abstract_collection__ContainerIterator__next(val* self) {
-abstract_collection__ContainerIterator__next(self);
+abstract_collection__ContainerIterator__next(self); /* Direct call abstract_collection#ContainerIterator#next on <self:Object(ContainerIterator[nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#ContainerIterator#init for (self: ContainerIterator[nullable Object], Container[nullable Object]) */
@@ -889,8 +753,8 @@ int idtype;
 const struct type* type_struct;
 const char* var_class_name;
 val* var_c /* var c: Container[nullable Object] */;
-/* Covariant cast for argument 0 (c) <p0:Container[nullable Object]> isa Container[ContainerIterator#0] */
-/* <p0:Container[nullable Object]> isa Container[ContainerIterator#0] */
+/* Covariant cast for argument 0 (c) <p0:Container[nullable Object]> isa Container[E] */
+/* <p0:Container[nullable Object]> isa Container[E] */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Containerabstract_collection__ContainerIterator_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -899,11 +763,11 @@ var = 0;
 } else {
 var = p0->type->type_table[cltype] == idtype;
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Container[ContainerIterator#0]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 192);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Container[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 211);
+show_backtrace(1);
 }
 var_c = p0;
 self->attrs[COLOR_abstract_collection__ContainerIterator___container].val = var_c; /* _container on <self:ContainerIterator[nullable Object]> */
@@ -911,7 +775,7 @@ RET_LABEL:;
 }
 /* method abstract_collection#ContainerIterator#init for (self: Object, Container[nullable Object]) */
 void VIRTUAL_abstract_collection__ContainerIterator__init(val* self, val* p0) {
-abstract_collection__ContainerIterator__init(self, p0);
+abstract_collection__ContainerIterator__init(self, p0); /* Direct call abstract_collection#ContainerIterator#init on <self:Object(ContainerIterator[nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#ContainerIterator#is_ok for (self: ContainerIterator[nullable Object]): Bool */
@@ -927,23 +791,48 @@ return var;
 short int VIRTUAL_abstract_collection__ContainerIterator__is_ok(val* self) {
 short int var /* : Bool */;
 short int var1 /* : Bool */;
-var1 = abstract_collection__ContainerIterator__is_ok(self);
+short int var3 /* : Bool */;
+{ /* Inline abstract_collection#ContainerIterator#is_ok (self) on <self:Object(ContainerIterator[nullable Object])> */
+var3 = self->attrs[COLOR_abstract_collection__ContainerIterator___is_ok].s; /* _is_ok on <self:Object(ContainerIterator[nullable Object])> */
+var1 = var3;
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
 return var;
 }
+/* method abstract_collection#ContainerIterator#is_ok= for (self: ContainerIterator[nullable Object], Bool) */
+void abstract_collection__ContainerIterator__is_ok_61d(val* self, short int p0) {
+self->attrs[COLOR_abstract_collection__ContainerIterator___is_ok].s = p0; /* _is_ok on <self:ContainerIterator[nullable Object]> */
+RET_LABEL:;
+}
+/* method abstract_collection#ContainerIterator#is_ok= for (self: Object, Bool) */
+void VIRTUAL_abstract_collection__ContainerIterator__is_ok_61d(val* self, short int p0) {
+{ /* Inline abstract_collection#ContainerIterator#is_ok= (self,p0) on <self:Object(ContainerIterator[nullable Object])> */
+self->attrs[COLOR_abstract_collection__ContainerIterator___is_ok].s = p0; /* _is_ok on <self:Object(ContainerIterator[nullable Object])> */
+RET_LABEL1:(void)0;
+}
+RET_LABEL:;
+}
 /* method abstract_collection#RemovableCollection#clear for (self: RemovableCollection[nullable Object]) */
 void abstract_collection__RemovableCollection__clear(val* self) {
 const char* var_class_name;
 var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "clear", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 202);
-exit(1);
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "clear", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 222);
+show_backtrace(1);
 RET_LABEL:;
 }
 /* method abstract_collection#RemovableCollection#clear for (self: Object) */
 void VIRTUAL_abstract_collection__RemovableCollection__clear(val* self) {
-abstract_collection__RemovableCollection__clear(self);
+const char* var_class_name;
+{ /* Inline abstract_collection#RemovableCollection#clear (self) on <self:Object(RemovableCollection[nullable Object])> */
+var_class_name = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "clear", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 222);
+show_backtrace(1);
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#RemovableCollection#remove for (self: RemovableCollection[nullable Object], nullable Object) */
@@ -955,8 +844,8 @@ const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
 const char* var_class_name1;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa RemovableCollection#0 */
-/* <p0:nullable Object> isa RemovableCollection#0 */
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__RemovableCollection_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -970,35 +859,30 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "RemovableCollection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 205);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 231);
+show_backtrace(1);
 }
 var_class_name1 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "remove", var_class_name1);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 205);
-exit(1);
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "remove", var_class_name1);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 231);
+show_backtrace(1);
 RET_LABEL:;
 }
 /* method abstract_collection#RemovableCollection#remove for (self: Object, nullable Object) */
 void VIRTUAL_abstract_collection__RemovableCollection__remove(val* self, val* p0) {
-abstract_collection__RemovableCollection__remove(self, p0);
-RET_LABEL:;
-}
-/* method abstract_collection#RemovableCollection#remove_all for (self: RemovableCollection[nullable Object], nullable Object) */
-void abstract_collection__RemovableCollection__remove_all(val* self, val* p0) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
-val* var_item /* var item: nullable Object */;
-short int var1 /* : Bool */;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa RemovableCollection#0 */
-/* <p0:nullable Object> isa RemovableCollection#0 */
+const char* var_class_name2;
+{ /* Inline abstract_collection#RemovableCollection#remove (self,p0) on <self:Object(RemovableCollection[nullable Object])> */
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__RemovableCollection_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -1012,66 +896,18 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "RemovableCollection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 208);
-exit(1);
-}
-var_item = p0;
-for(;;) {
-var1 = ((short int (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Collection__has]))(self, var_item) /* has on <self:RemovableCollection[nullable Object]>*/;
-if (!var1) break;
-((void (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__RemovableCollection__remove]))(self, var_item) /* remove on <self:RemovableCollection[nullable Object]>*/;
-CONTINUE_label: (void)0;
-}
-BREAK_label: (void)0;
-RET_LABEL:;
-}
-/* method abstract_collection#RemovableCollection#remove_all for (self: Object, nullable Object) */
-void VIRTUAL_abstract_collection__RemovableCollection__remove_all(val* self, val* p0) {
-abstract_collection__RemovableCollection__remove_all(self, p0);
-RET_LABEL:;
-}
-/* method abstract_collection#SimpleCollection#add for (self: SimpleCollection[nullable Object], nullable Object) */
-void abstract_collection__SimpleCollection__add(val* self, val* p0) {
-short int var /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-short int is_nullable;
-const char* var_class_name;
-const char* var_class_name1;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa SimpleCollection#0 */
-/* <p0:nullable Object> isa SimpleCollection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__SimpleCollection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-is_nullable = type_struct->is_nullable;
-if(p0 == NULL) {
-var = is_nullable;
-} else {
-if(cltype >= p0->type->table_size) {
-var = 0;
-} else {
-var = p0->type->type_table[cltype] == idtype;
-}
-}
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "SimpleCollection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 215);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 231);
+show_backtrace(1);
 }
-var_class_name1 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "add", var_class_name1);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 215);
-exit(1);
-RET_LABEL:;
+var_class_name2 = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "remove", var_class_name2);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 231);
+show_backtrace(1);
+RET_LABEL1:(void)0;
 }
-/* method abstract_collection#SimpleCollection#add for (self: Object, nullable Object) */
-void VIRTUAL_abstract_collection__SimpleCollection__add(val* self, val* p0) {
-abstract_collection__SimpleCollection__add(self, p0);
 RET_LABEL:;
 }
 /* method abstract_collection#SimpleCollection#add_all for (self: SimpleCollection[nullable Object], Collection[nullable Object]) */
@@ -1082,12 +918,14 @@ int idtype;
 const struct type* type_struct;
 const char* var_class_name;
 val* var_coll /* var coll: Collection[nullable Object] */;
+val* var_ /* var : Collection[nullable Object] */;
 val* var1 /* : Iterator[nullable Object] */;
-short int var2 /* : Bool */;
-val* var3 /* : nullable Object */;
+val* var_2 /* var : Iterator[nullable Object] */;
+short int var3 /* : Bool */;
+val* var4 /* : nullable Object */;
 val* var_i /* var i: nullable Object */;
-/* Covariant cast for argument 0 (coll) <p0:Collection[nullable Object]> isa Collection[SimpleCollection#0] */
-/* <p0:Collection[nullable Object]> isa Collection[SimpleCollection#0] */
+/* Covariant cast for argument 0 (coll) <p0:Collection[nullable Object]> isa Collection[E] */
+/* <p0:Collection[nullable Object]> isa Collection[E] */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collectionabstract_collection__SimpleCollection_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -1096,313 +934,241 @@ var = 0;
 } else {
 var = p0->type->type_table[cltype] == idtype;
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[SimpleCollection#0]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 219);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 260);
+show_backtrace(1);
 }
 var_coll = p0;
-var1 = ((val* (*)(val*))(var_coll->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_coll) /* iterator on <var_coll:Collection[nullable Object]>*/;
+var_ = var_coll;
+{
+var1 = ((val* (*)(val*))(var_->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[nullable Object]>*/;
+}
+var_2 = var1;
 for(;;) {
-var2 = ((short int (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var1) /* is_ok on <var1:Iterator[nullable Object]>*/;
-if(!var2) break;
-var3 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__item]))(var1) /* item on <var1:Iterator[nullable Object]>*/;
-var_i = var3;
+{
+var3 = ((short int (*)(val*))(var_2->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_2) /* is_ok on <var_2:Iterator[nullable Object]>*/;
+}
+if (var3){
+{
+var4 = ((val* (*)(val*))(var_2->class->vft[COLOR_abstract_collection__Iterator__item]))(var_2) /* item on <var_2:Iterator[nullable Object]>*/;
+}
+var_i = var4;
+{
 ((void (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__SimpleCollection__add]))(self, var_i) /* add on <self:SimpleCollection[nullable Object]>*/;
-CONTINUE_label: (void)0;
-((void (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__next]))(var1) /* next on <var1:Iterator[nullable Object]>*/;
+}
+{
+((void (*)(val*))(var_2->class->vft[COLOR_abstract_collection__Iterator__next]))(var_2) /* next on <var_2:Iterator[nullable Object]>*/;
+}
+} else {
+goto BREAK_label;
+}
 }
 BREAK_label: (void)0;
+{
+{ /* Inline abstract_collection#Iterator#finish (var_2) on <var_2:Iterator[nullable Object]> */
+RET_LABEL5:(void)0;
+}
+}
 RET_LABEL:;
 }
 /* method abstract_collection#SimpleCollection#add_all for (self: Object, Collection[nullable Object]) */
 void VIRTUAL_abstract_collection__SimpleCollection__add_all(val* self, val* p0) {
-abstract_collection__SimpleCollection__add_all(self, p0);
+abstract_collection__SimpleCollection__add_all(self, p0); /* Direct call abstract_collection#SimpleCollection#add_all on <self:Object(SimpleCollection[nullable Object])>*/
 RET_LABEL:;
 }
-/* method abstract_collection#Set#has_only for (self: Set[Object], Object): Bool */
-short int abstract_collection__Set__has_only(val* self, val* p0) {
+/* method abstract_collection#Set#== for (self: Set[Object], nullable Object): Bool */
+short int abstract_collection__Set___61d_61d(val* self, val* p0) {
 short int var /* : Bool */;
+val* var_other /* var other: nullable Object */;
 short int var1 /* : Bool */;
 int cltype;
 int idtype;
-const struct type* type_struct;
-const char* var_class_name;
-val* var_item /* var item: Object */;
-long var2 /* : Int */;
-long var_l /* var l: Int */;
-long var3 /* : Int */;
-short int var4 /* : Bool */;
+short int var2 /* : Bool */;
+short int var3 /* : Bool */;
+long var4 /* : Int */;
+long var5 /* : Int */;
 short int var6 /* : Bool */;
 short int var7 /* : Bool */;
-long var8 /* : Int */;
 short int var9 /* : Bool */;
+short int var10 /* : Bool */;
 short int var11 /* : Bool */;
 short int var12 /* : Bool */;
-short int var13 /* : Bool */;
-/* Covariant cast for argument 0 (item) <p0:Object> isa Collection#0 */
-/* <p0:Object> isa Collection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+int cltype13;
+int idtype14;
+const struct type* type_struct;
+const char* var_class_name;
+short int var15 /* : Bool */;
+var_other = p0;
+/* <var_other:nullable Object> isa Set[Object] */
+cltype = type_abstract_collection__Setkernel__Object.color;
+idtype = type_abstract_collection__Setkernel__Object.id;
+if(var_other == NULL) {
 var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
-}
-if (!var1) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 235);
-exit(1);
+if(cltype >= var_other->type->table_size) {
+var1 = 0;
+} else {
+var1 = var_other->type->type_table[cltype] == idtype;
 }
-var_item = p0;
-var2 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Set[Object]>*/;
-var_l = var2;
-var3 = 1;
-{ /* Inline kernel#Int#== (var_l,var3) */
-var6 = var_l == var3;
-var4 = var6;
-goto RET_LABEL5;
-RET_LABEL5:(void)0;
 }
-if (var4){
-var7 = ((short int (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Collection__has]))(self, var_item) /* has on <self:Set[Object]>*/;
-var = var7;
+var2 = !var1;
+if (var2){
+var3 = 0;
+var = var3;
 goto RET_LABEL;
 } else {
-var8 = 0;
-{ /* Inline kernel#Int#== (var_l,var8) */
-var11 = var_l == var8;
-var9 = var11;
-goto RET_LABEL10;
-RET_LABEL10:(void)0;
 }
-if (var9){
-var12 = 1;
-var = var12;
+{
+var4 = ((long (*)(val*))(var_other->class->vft[COLOR_abstract_collection__Collection__length]))(var_other) /* length on <var_other:nullable Object(Set[Object])>*/;
+}
+{
+var5 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Set[Object]>*/;
+}
+{
+{ /* Inline kernel#Int#!= (var4,var5) on <var4:Int> */
+var9 = var4 == var5;
+var10 = !var9;
+var7 = var10;
+goto RET_LABEL8;
+RET_LABEL8:(void)0;
+}
+var6 = var7;
+}
+if (var6){
+var11 = 0;
+var = var11;
 goto RET_LABEL;
 } else {
-var13 = 0;
-var = var13;
-goto RET_LABEL;
 }
+/* <var_other:nullable Object(Set[Object])> isa Collection[E] */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collectionabstract_collection__Set_FT0];
+cltype13 = type_struct->color;
+idtype14 = type_struct->id;
+if(cltype13 >= var_other->type->table_size) {
+var12 = 0;
+} else {
+var12 = var_other->type->type_table[cltype13] == idtype14;
+}
+if (unlikely(!var12)) {
+var_class_name = var_other == NULL ? "null" : var_other->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 311);
+show_backtrace(1);
+}
+{
+var15 = abstract_collection__Collection__has_all(self, var_other);
 }
+var = var15;
+goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Set#has_only for (self: Object, nullable Object): Bool */
-short int VIRTUAL_abstract_collection__Set__has_only(val* self, val* p0) {
-short int var /* : Bool */;
+/* method abstract_collection#Set#== for (self: Object, nullable Object): Bool */
+short int VIRTUAL_abstract_collection__Set___61d_61d(val* self, val* p0) {
+short int var /* : Bool */;
 short int var1 /* : Bool */;
-var1 = abstract_collection__Set__has_only(self, p0);
+var1 = abstract_collection__Set___61d_61d(self, p0);
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Set#count for (self: Set[Object], Object): Int */
-long abstract_collection__Set__count(val* self, val* p0) {
-long var /* : Int */;
-short int var1 /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-const char* var_class_name;
-val* var_item /* var item: Object */;
-short int var2 /* : Bool */;
-long var3 /* : Int */;
-long var4 /* : Int */;
-/* Covariant cast for argument 0 (item) <p0:Object> isa Collection#0 */
-/* <p0:Object> isa Collection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
-var1 = 0;
-} else {
-var1 = p0->type->type_table[cltype] == idtype;
-}
-if (!var1) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 247);
-exit(1);
-}
-var_item = p0;
-var2 = ((short int (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Collection__has]))(self, var_item) /* has on <self:Set[Object]>*/;
-if (var2){
-var3 = 1;
-var = var3;
-goto RET_LABEL;
-} else {
-var4 = 0;
-var = var4;
-goto RET_LABEL;
-}
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Set#count for (self: Object, nullable Object): Int */
-long VIRTUAL_abstract_collection__Set__count(val* self, val* p0) {
+/* method abstract_collection#Set#hash for (self: Set[Object]): Int */
+long abstract_collection__Set__hash(val* self) {
 long var /* : Int */;
 long var1 /* : Int */;
-var1 = abstract_collection__Set__count(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Set#remove_all for (self: Set[Object], Object) */
-void abstract_collection__Set__remove_all(val* self, val* p0) {
-short int var /* : Bool */;
+long var2 /* : Int */;
+long var3 /* : Int */;
+short int var5 /* : Bool */;
 int cltype;
 int idtype;
-const struct type* type_struct;
 const char* var_class_name;
-val* var_item /* var item: Object */;
-/* Covariant cast for argument 0 (item) <p0:Object> isa RemovableCollection#0 */
-/* <p0:Object> isa RemovableCollection#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__RemovableCollection_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
-var = 0;
-} else {
-var = p0->type->type_table[cltype] == idtype;
-}
-if (!var) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "RemovableCollection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 257);
-exit(1);
-}
-var_item = p0;
-((void (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__RemovableCollection__remove]))(self, var_item) /* remove on <self:Set[Object]>*/;
-RET_LABEL:;
-}
-/* method abstract_collection#Set#remove_all for (self: Object, nullable Object) */
-void VIRTUAL_abstract_collection__Set__remove_all(val* self, val* p0) {
-abstract_collection__Set__remove_all(self, p0);
-RET_LABEL:;
-}
-/* method abstract_collection#Set#== for (self: Set[Object], nullable Object): Bool */
-short int abstract_collection__Set___61d_61d(val* self, val* p0) {
-short int var /* : Bool */;
-val* var_other /* var other: nullable Object */;
-short int var1 /* : Bool */;
-int cltype;
-int idtype;
-short int var2 /* : Bool */;
-short int var3 /* : Bool */;
-long var4 /* : Int */;
-long var5 /* : Int */;
-short int var6 /* : Bool */;
-short int var8 /* : Bool */;
+long var6 /* : Int */;
+long var_res /* var res: Int */;
+val* var_ /* var : Set[Object] */;
+val* var7 /* : Iterator[nullable Object] */;
+val* var_8 /* var : Iterator[Object] */;
 short int var9 /* : Bool */;
-short int var10 /* : Bool */;
-short int var11 /* : Bool */;
-int cltype12;
-int idtype13;
-const struct type* type_struct;
-const char* var_class_name;
+val* var10 /* : nullable Object */;
+val* var_e /* var e: Object */;
+long var11 /* : Int */;
+long var12 /* : Int */;
 short int var14 /* : Bool */;
-var_other = p0;
-/* <var_other:nullable Object> isa Set[Object] */
-cltype = type_abstract_collection__Setkernel__Object.color;
-idtype = type_abstract_collection__Setkernel__Object.id;
-if(var_other == NULL) {
-var1 = 0;
-} else {
-if(cltype >= var_other->type->table_size) {
-var1 = 0;
-} else {
-var1 = var_other->type->type_table[cltype] == idtype;
+int cltype15;
+int idtype16;
+const char* var_class_name17;
+long var18 /* : Int */;
+var1 = 23;
+{
+var2 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Set[Object]>*/;
 }
+{
+{ /* Inline kernel#Int#+ (var1,var2) on <var1:Int> */
+/* Covariant cast for argument 0 (i) <var2:Int> isa OTHER */
+/* <var2:Int> isa OTHER */
+var5 = 1; /* easy <var2:Int> isa OTHER*/
+if (unlikely(!var5)) {
+var_class_name = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
 }
-var2 = !var1;
-if (var2){
-var3 = 0;
-var = var3;
-goto RET_LABEL;
-} else {
+var6 = var1 + var2;
+var3 = var6;
+goto RET_LABEL4;
+RET_LABEL4:(void)0;
 }
-var4 = ((long (*)(val*))(var_other->class->vft[COLOR_abstract_collection__Collection__length]))(var_other) /* length on <var_other:nullable Object(Set[Object])>*/;
-var5 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Set[Object]>*/;
-{ /* Inline kernel#Int#!= (var4,var5) */
-var8 = var4 == var5;
-var9 = !var8;
-var6 = var9;
-goto RET_LABEL7;
-RET_LABEL7:(void)0;
 }
-if (var6){
-var10 = 0;
-var = var10;
-goto RET_LABEL;
-} else {
+var_res = var3;
+var_ = self;
+{
+var7 = ((val* (*)(val*))(var_->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Set[Object]>*/;
 }
-/* <var_other:nullable Object(Set[Object])> isa Collection[Set#0] */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collectionabstract_collection__Set_FT0];
-cltype12 = type_struct->color;
-idtype13 = type_struct->id;
-if(cltype12 >= var_other->type->table_size) {
-var11 = 0;
-} else {
-var11 = var_other->type->type_table[cltype12] == idtype13;
+var_8 = var7;
+for(;;) {
+{
+var9 = ((short int (*)(val*))(var_8->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_8) /* is_ok on <var_8:Iterator[Object]>*/;
 }
-if (!var11) {
-var_class_name = var_other == NULL ? "null" : var_other->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[Set#0]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 265);
-exit(1);
+if (var9){
+{
+var10 = ((val* (*)(val*))(var_8->class->vft[COLOR_abstract_collection__Iterator__item]))(var_8) /* item on <var_8:Iterator[Object]>*/;
+}
+var_e = var10;
+{
+var11 = ((long (*)(val*))(var_e->class->vft[COLOR_kernel__Object__hash]))(var_e) /* hash on <var_e:Object>*/;
+}
+{
+{ /* Inline kernel#Int#+ (var_res,var11) on <var_res:Int> */
+/* Covariant cast for argument 0 (i) <var11:Int> isa OTHER */
+/* <var11:Int> isa OTHER */
+var14 = 1; /* easy <var11:Int> isa OTHER*/
+if (unlikely(!var14)) {
+var_class_name17 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name17);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var18 = var_res + var11;
+var12 = var18;
+goto RET_LABEL13;
+RET_LABEL13:(void)0;
 }
-var14 = ((short int (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Collection__has_all]))(self, var_other) /* has_all on <self:Set[Object]>*/;
-var = var14;
-goto RET_LABEL;
-RET_LABEL:;
-return var;
 }
-/* method abstract_collection#Set#== for (self: Object, nullable Object): Bool */
-short int VIRTUAL_abstract_collection__Set___61d_61d(val* self, val* p0) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-var1 = abstract_collection__Set___61d_61d(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
+var_res = var12;
+{
+((void (*)(val*))(var_8->class->vft[COLOR_abstract_collection__Iterator__next]))(var_8) /* next on <var_8:Iterator[Object]>*/;
 }
-/* method abstract_collection#Set#hash for (self: Set[Object]): Int */
-long abstract_collection__Set__hash(val* self) {
-long var /* : Int */;
-long var1 /* : Int */;
-long var_res /* var res: Int */;
-val* var2 /* : Iterator[nullable Object] */;
-short int var3 /* : Bool */;
-val* var4 /* : nullable Object */;
-val* var_e /* var e: Object */;
-long var5 /* : Int */;
-long var6 /* : Int */;
-long var8 /* : Int */;
-var1 = 0;
-var_res = var1;
-var2 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:Set[Object]>*/;
-for(;;) {
-var3 = ((short int (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var2) /* is_ok on <var2:Iterator[nullable Object]>*/;
-if(!var3) break;
-var4 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__item]))(var2) /* item on <var2:Iterator[nullable Object]>*/;
-var_e = var4;
-var5 = kernel__Int__hash(var_res);
-{ /* Inline kernel#Int#+ (var_res,var5) */
-var8 = var_res + var5;
-var6 = var8;
-goto RET_LABEL7;
-RET_LABEL7:(void)0;
+} else {
+goto BREAK_label;
 }
-var_res = var6;
-CONTINUE_label: (void)0;
-((void (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__next]))(var2) /* next on <var2:Iterator[nullable Object]>*/;
 }
 BREAK_label: (void)0;
+{
+{ /* Inline abstract_collection#Iterator#finish (var_8) on <var_8:Iterator[Object]> */
+RET_LABEL19:(void)0;
+}
+}
 var = var_res;
 goto RET_LABEL;
 RET_LABEL:;
@@ -1417,67 +1183,20 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapRead#[] for (self: MapRead[Object, nullable Object], Object): nullable Object */
-val* abstract_collection__MapRead___91d_93d(val* self, val* p0) {
-val* var /* : nullable Object */;
-short int var1 /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-const char* var_class_name;
-const char* var_class_name2;
-/* Covariant cast for argument 0 (key) <p0:Object> isa MapRead#0 */
-/* <p0:Object> isa MapRead#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapRead_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
-var1 = 0;
-} else {
-var1 = p0->type->type_table[cltype] == idtype;
-}
-if (!var1) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapRead#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 279);
-exit(1);
-}
-var_class_name2 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "[]", var_class_name2);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 279);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#[] for (self: Object, Object): nullable Object */
-val* VIRTUAL_abstract_collection__MapRead___91d_93d(val* self, val* p0) {
-val* var /* : nullable Object */;
-val* var1 /* : nullable Object */;
-var1 = abstract_collection__MapRead___91d_93d(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#get_or_default for (self: MapRead[Object, nullable Object], Object, nullable Object): nullable Object */
-val* abstract_collection__MapRead__get_or_default(val* self, val* p0, val* p1) {
+/* method abstract_collection#MapRead#get_or_null for (self: MapRead[Object, nullable Object], Object): nullable Object */
+val* abstract_collection__MapRead__get_or_null(val* self, val* p0) {
 val* var /* : nullable Object */;
 short int var1 /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 const char* var_class_name;
-short int var2 /* : Bool */;
-int cltype3;
-int idtype4;
-const struct type* type_struct5;
-short int is_nullable;
-const char* var_class_name6;
 val* var_key /* var key: Object */;
-val* var_default /* var default: nullable Object */;
-short int var7 /* : Bool */;
-val* var8 /* : nullable Object */;
-/* Covariant cast for argument 0 (key) <p0:Object> isa MapRead#0 */
-/* <p0:Object> isa MapRead#0 */
+short int var2 /* : Bool */;
+val* var3 /* : nullable Object */;
+val* var4 /* : null */;
+/* Covariant cast for argument 0 (key) <p0:Object> isa K */
+/* <p0:Object> isa K */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapRead_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -1486,52 +1205,35 @@ var1 = 0;
 } else {
 var1 = p0->type->type_table[cltype] == idtype;
 }
-if (!var1) {
+if (unlikely(!var1)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapRead#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 282);
-exit(1);
-}
-/* Covariant cast for argument 1 (default) <p1:nullable Object> isa MapRead#1 */
-/* <p1:nullable Object> isa MapRead#1 */
-type_struct5 = self->type->resolution_table->types[COLOR_abstract_collection__MapRead_FT1];
-cltype3 = type_struct5->color;
-idtype4 = type_struct5->id;
-is_nullable = type_struct5->is_nullable;
-if(p1 == NULL) {
-var2 = is_nullable;
-} else {
-if(cltype3 >= p1->type->table_size) {
-var2 = 0;
-} else {
-var2 = p1->type->type_table[cltype3] == idtype4;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "K", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 358);
+show_backtrace(1);
 }
+var_key = p0;
+{
+var2 = abstract_collection__MapRead__has_key(self, var_key);
 }
-if (!var2) {
-var_class_name6 = p1 == NULL ? "null" : p1->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapRead#1", var_class_name6);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 282);
-exit(1);
+if (var2){
+{
+var3 = ((val* (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__MapRead___91d_93d]))(self, var_key) /* [] on <self:MapRead[Object, nullable Object]>*/;
 }
-var_key = p0;
-var_default = p1;
-var7 = ((short int (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__MapRead__has_key]))(self, var_key) /* has_key on <self:MapRead[Object, nullable Object]>*/;
-if (var7){
-var8 = ((val* (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__MapRead___91d_93d]))(self, var_key) /* [] on <self:MapRead[Object, nullable Object]>*/;
-var = var8;
+var = var3;
 goto RET_LABEL;
 } else {
 }
-var = var_default;
+var4 = NULL;
+var = var4;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapRead#get_or_default for (self: Object, Object, nullable Object): nullable Object */
-val* VIRTUAL_abstract_collection__MapRead__get_or_default(val* self, val* p0, val* p1) {
+/* method abstract_collection#MapRead#get_or_null for (self: Object, Object): nullable Object */
+val* VIRTUAL_abstract_collection__MapRead__get_or_null(val* self, val* p0) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = abstract_collection__MapRead__get_or_default(self, p0, p1);
+var1 = abstract_collection__MapRead__get_or_null(self, p0);
 var = var1;
 RET_LABEL:;
 return var;
@@ -1547,8 +1249,8 @@ const char* var_class_name;
 val* var_key /* var key: Object */;
 val* var2 /* : Collection[Object] */;
 short int var3 /* : Bool */;
-/* Covariant cast for argument 0 (key) <p0:Object> isa MapRead#0 */
-/* <p0:Object> isa MapRead#0 */
+/* Covariant cast for argument 0 (key) <p0:Object> isa K */
+/* <p0:Object> isa K */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapRead_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -1557,15 +1259,19 @@ var1 = 0;
 } else {
 var1 = p0->type->type_table[cltype] == idtype;
 }
-if (!var1) {
+if (unlikely(!var1)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapRead#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 289);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "K", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 385);
+show_backtrace(1);
 }
 var_key = p0;
+{
 var2 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__MapRead__keys]))(self) /* keys on <self:MapRead[Object, nullable Object]>*/;
+}
+{
 var3 = ((short int (*)(val*, val*))(var2->class->vft[COLOR_abstract_collection__Collection__has]))(var2, var_key) /* has on <var2:Collection[Object]>*/;
+}
 var = var3;
 goto RET_LABEL;
 RET_LABEL:;
@@ -1580,377 +1286,100 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapRead#iterator for (self: MapRead[Object, nullable Object]): MapIterator[Object, nullable Object] */
-val* abstract_collection__MapRead__iterator(val* self) {
-val* var /* : MapIterator[Object, nullable Object] */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "iterator", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 292);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#iterator for (self: Object): MapIterator[Object, nullable Object] */
-val* VIRTUAL_abstract_collection__MapRead__iterator(val* self) {
-val* var /* : MapIterator[Object, nullable Object] */;
-val* var1 /* : MapIterator[Object, nullable Object] */;
-var1 = abstract_collection__MapRead__iterator(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#values for (self: MapRead[Object, nullable Object]): Collection[nullable Object] */
-val* abstract_collection__MapRead__values(val* self) {
-val* var /* : Collection[nullable Object] */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "values", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 295);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#values for (self: Object): Collection[nullable Object] */
-val* VIRTUAL_abstract_collection__MapRead__values(val* self) {
-val* var /* : Collection[nullable Object] */;
-val* var1 /* : Collection[nullable Object] */;
-var1 = abstract_collection__MapRead__values(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#keys for (self: MapRead[Object, nullable Object]): Collection[Object] */
-val* abstract_collection__MapRead__keys(val* self) {
-val* var /* : Collection[Object] */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "keys", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 300);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#keys for (self: Object): Collection[Object] */
-val* VIRTUAL_abstract_collection__MapRead__keys(val* self) {
-val* var /* : Collection[Object] */;
-val* var1 /* : Collection[Object] */;
-var1 = abstract_collection__MapRead__keys(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#is_empty for (self: MapRead[Object, nullable Object]): Bool */
-short int abstract_collection__MapRead__is_empty(val* self) {
-short int var /* : Bool */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "is_empty", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 305);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#is_empty for (self: Object): Bool */
-short int VIRTUAL_abstract_collection__MapRead__is_empty(val* self) {
-short int var /* : Bool */;
+/* method abstract_collection#MapRead#provide_default_value for (self: MapRead[Object, nullable Object], Object): nullable Object */
+val* abstract_collection__MapRead__provide_default_value(val* self, val* p0) {
+val* var /* : nullable Object */;
 short int var1 /* : Bool */;
-var1 = abstract_collection__MapRead__is_empty(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#length for (self: MapRead[Object, nullable Object]): Int */
-long abstract_collection__MapRead__length(val* self) {
-long var /* : Int */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "length", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 308);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapRead#length for (self: Object): Int */
-long VIRTUAL_abstract_collection__MapRead__length(val* self) {
-long var /* : Int */;
-long var1 /* : Int */;
-var1 = abstract_collection__MapRead__length(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Map#[]= for (self: Map[Object, nullable Object], Object, nullable Object) */
-void abstract_collection__Map___91d_93d_61d(val* self, val* p0, val* p1) {
-short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 const char* var_class_name;
-short int var1 /* : Bool */;
-int cltype2;
-int idtype3;
-const struct type* type_struct4;
-short int is_nullable;
-const char* var_class_name5;
-const char* var_class_name6;
-/* Covariant cast for argument 0 (key) <p0:Object> isa Map#0 */
-/* <p0:Object> isa Map#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Map_FT0];
+val* var_key /* var key: Object */;
+/* Covariant cast for argument 0 (key) <p0:Object> isa K */
+/* <p0:Object> isa K */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapRead_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
 if(cltype >= p0->type->table_size) {
-var = 0;
-} else {
-var = p0->type->type_table[cltype] == idtype;
-}
-if (!var) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Map#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 338);
-exit(1);
-}
-/* Covariant cast for argument 1 (item) <p1:nullable Object> isa Map#1 */
-/* <p1:nullable Object> isa Map#1 */
-type_struct4 = self->type->resolution_table->types[COLOR_abstract_collection__Map_FT1];
-cltype2 = type_struct4->color;
-idtype3 = type_struct4->id;
-is_nullable = type_struct4->is_nullable;
-if(p1 == NULL) {
-var1 = is_nullable;
-} else {
-if(cltype2 >= p1->type->table_size) {
 var1 = 0;
 } else {
-var1 = p1->type->type_table[cltype2] == idtype3;
-}
-}
-if (!var1) {
-var_class_name5 = p1 == NULL ? "null" : p1->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Map#1", var_class_name5);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 338);
-exit(1);
-}
-var_class_name6 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "[]=", var_class_name6);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 338);
-exit(1);
-RET_LABEL:;
-}
-/* method abstract_collection#Map#[]= for (self: Object, Object, nullable Object) */
-void VIRTUAL_abstract_collection__Map___91d_93d_61d(val* self, val* p0, val* p1) {
-abstract_collection__Map___91d_93d_61d(self, p0, p1);
-RET_LABEL:;
-}
-/* method abstract_collection#Map#recover_with for (self: Map[Object, nullable Object], Map[Object, nullable Object]) */
-void abstract_collection__Map__recover_with(val* self, val* p0) {
-short int var /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-const char* var_class_name;
-val* var_map /* var map: Map[Object, nullable Object] */;
-val* var1 /* : MapIterator[Object, nullable Object] */;
-val* var_i /* var i: MapIterator[Object, nullable Object] */;
-short int var2 /* : Bool */;
-val* var3 /* : Object */;
-val* var4 /* : nullable Object */;
-/* Covariant cast for argument 0 (map) <p0:Map[Object, nullable Object]> isa Map[Map#0, Map#1] */
-/* <p0:Map[Object, nullable Object]> isa Map[Map#0, Map#1] */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Mapabstract_collection__Map_FT0abstract_collection__Map_FT1];
-cltype = type_struct->color;
-idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
-var = 0;
-} else {
-var = p0->type->type_table[cltype] == idtype;
+var1 = p0->type->type_table[cltype] == idtype;
 }
-if (!var) {
+if (unlikely(!var1)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[Map#0, Map#1]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 341);
-exit(1);
-}
-var_map = p0;
-var1 = ((val* (*)(val*))(var_map->class->vft[COLOR_abstract_collection__MapRead__iterator]))(var_map) /* iterator on <var_map:Map[Object, nullable Object]>*/;
-var_i = var1;
-for(;;) {
-var2 = ((short int (*)(val*))(var_i->class->vft[COLOR_abstract_collection__MapIterator__is_ok]))(var_i) /* is_ok on <var_i:MapIterator[Object, nullable Object]>*/;
-if (!var2) break;
-var3 = ((val* (*)(val*))(var_i->class->vft[COLOR_abstract_collection__MapIterator__key]))(var_i) /* key on <var_i:MapIterator[Object, nullable Object]>*/;
-var4 = ((val* (*)(val*))(var_i->class->vft[COLOR_abstract_collection__MapIterator__item]))(var_i) /* item on <var_i:MapIterator[Object, nullable Object]>*/;
-((void (*)(val*, val*, val*))(self->class->vft[COLOR_abstract_collection__Map___91d_93d_61d]))(self, var3, var4) /* []= on <self:Map[Object, nullable Object]>*/;
-((void (*)(val*))(var_i->class->vft[COLOR_abstract_collection__MapIterator__next]))(var_i) /* next on <var_i:MapIterator[Object, nullable Object]>*/;
-CONTINUE_label: (void)0;
-}
-BREAK_label: (void)0;
-RET_LABEL:;
-}
-/* method abstract_collection#Map#recover_with for (self: Object, Map[Object, nullable Object]) */
-void VIRTUAL_abstract_collection__Map__recover_with(val* self, val* p0) {
-abstract_collection__Map__recover_with(self, p0);
-RET_LABEL:;
-}
-/* method abstract_collection#Map#clear for (self: Map[Object, nullable Object]) */
-void abstract_collection__Map__clear(val* self) {
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "clear", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 352);
-exit(1);
-RET_LABEL:;
-}
-/* method abstract_collection#Map#clear for (self: Object) */
-void VIRTUAL_abstract_collection__Map__clear(val* self) {
-abstract_collection__Map__clear(self);
-RET_LABEL:;
-}
-/* method abstract_collection#Map#values for (self: Map[Object, nullable Object]): RemovableCollection[nullable Object] */
-val* abstract_collection__Map__values(val* self) {
-val* var /* : RemovableCollection[nullable Object] */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "values", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 355);
-exit(1);
-RET_LABEL:;
-return var;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "K", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 429);
+show_backtrace(1);
 }
-/* method abstract_collection#Map#values for (self: Object): Collection[nullable Object] */
-val* VIRTUAL_abstract_collection__Map__values(val* self) {
-val* var /* : Collection[nullable Object] */;
-val* var1 /* : RemovableCollection[nullable Object] */;
-var1 = abstract_collection__Map__values(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Map#keys for (self: Map[Object, nullable Object]): RemovableCollection[Object] */
-val* abstract_collection__Map__keys(val* self) {
-val* var /* : RemovableCollection[Object] */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "keys", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 357);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#Map#keys for (self: Object): Collection[Object] */
-val* VIRTUAL_abstract_collection__Map__keys(val* self) {
-val* var /* : Collection[Object] */;
-val* var1 /* : RemovableCollection[Object] */;
-var1 = abstract_collection__Map__keys(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapIterator#item for (self: MapIterator[Object, nullable Object]): nullable Object */
-val* abstract_collection__MapIterator__item(val* self) {
-val* var /* : nullable Object */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "item", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 362);
-exit(1);
+var_key = p0;
+PRINT_ERROR("Runtime error: %s", "Aborted");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 434);
+show_backtrace(1);
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapIterator#item for (self: Object): nullable Object */
-val* VIRTUAL_abstract_collection__MapIterator__item(val* self) {
+/* method abstract_collection#MapRead#provide_default_value for (self: Object, Object): nullable Object */
+val* VIRTUAL_abstract_collection__MapRead__provide_default_value(val* self, val* p0) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = abstract_collection__MapIterator__item(self);
-var = var1;
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapIterator#key for (self: MapIterator[Object, nullable Object]): Object */
-val* abstract_collection__MapIterator__key(val* self) {
-val* var /* : Object */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "key", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 366);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#MapIterator#key for (self: Object): Object */
-val* VIRTUAL_abstract_collection__MapIterator__key(val* self) {
-val* var /* : Object */;
-val* var1 /* : Object */;
-var1 = abstract_collection__MapIterator__key(self);
+var1 = abstract_collection__MapRead__provide_default_value(self, p0);
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapIterator#next for (self: MapIterator[Object, nullable Object]) */
-void abstract_collection__MapIterator__next(val* self) {
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "next", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 370);
-exit(1);
+/* method abstract_collection#MapIterator#finish for (self: MapIterator[Object, nullable Object]) */
+void abstract_collection__MapIterator__finish(val* self) {
 RET_LABEL:;
 }
-/* method abstract_collection#MapIterator#next for (self: Object) */
-void VIRTUAL_abstract_collection__MapIterator__next(val* self) {
-abstract_collection__MapIterator__next(self);
-RET_LABEL:;
-}
-/* method abstract_collection#MapIterator#is_ok for (self: MapIterator[Object, nullable Object]): Bool */
-short int abstract_collection__MapIterator__is_ok(val* self) {
-short int var /* : Bool */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "is_ok", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 374);
-exit(1);
-RET_LABEL:;
-return var;
+/* method abstract_collection#MapIterator#finish for (self: Object) */
+void VIRTUAL_abstract_collection__MapIterator__finish(val* self) {
+{ /* Inline abstract_collection#MapIterator#finish (self) on <self:Object(MapIterator[Object, nullable Object])> */
+RET_LABEL1:(void)0;
 }
-/* method abstract_collection#MapIterator#is_ok for (self: Object): Bool */
-short int VIRTUAL_abstract_collection__MapIterator__is_ok(val* self) {
-short int var /* : Bool */;
-short int var1 /* : Bool */;
-var1 = abstract_collection__MapIterator__is_ok(self);
-var = var1;
 RET_LABEL:;
-return var;
 }
-/* method abstract_collection#MapKeysIterator#iterator for (self: MapKeysIterator[Object, nullable Object]): MapIterator[Object, nullable Object] */
-val* abstract_collection__MapKeysIterator__iterator(val* self) {
+/* method abstract_collection#MapKeysIterator#original_iterator for (self: MapKeysIterator[Object, nullable Object]): MapIterator[Object, nullable Object] */
+val* abstract_collection__MapKeysIterator__original_iterator(val* self) {
 val* var /* : MapIterator[Object, nullable Object] */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-var1 = self->attrs[COLOR_abstract_collection__MapKeysIterator___64diterator].val; /* @iterator on <self:MapKeysIterator[Object, nullable Object]> */
-if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s", "Uninitialized attribute @iterator");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 384);
-exit(1);
+var1 = self->attrs[COLOR_abstract_collection__MapKeysIterator___original_iterator].val; /* _original_iterator on <self:MapKeysIterator[Object, nullable Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 554);
+show_backtrace(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapKeysIterator#iterator for (self: Object): MapIterator[Object, nullable Object] */
-val* VIRTUAL_abstract_collection__MapKeysIterator__iterator(val* self) {
+/* method abstract_collection#MapKeysIterator#original_iterator for (self: Object): MapIterator[Object, nullable Object] */
+val* VIRTUAL_abstract_collection__MapKeysIterator__original_iterator(val* self) {
 val* var /* : MapIterator[Object, nullable Object] */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-var1 = abstract_collection__MapKeysIterator__iterator(self);
+val* var3 /* : MapIterator[Object, nullable Object] */;
+{ /* Inline abstract_collection#MapKeysIterator#original_iterator (self) on <self:Object(MapKeysIterator[Object, nullable Object])> */
+var3 = self->attrs[COLOR_abstract_collection__MapKeysIterator___original_iterator].val; /* _original_iterator on <self:Object(MapKeysIterator[Object, nullable Object])> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 554);
+show_backtrace(1);
+}
+var1 = var3;
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapKeysIterator#iterator= for (self: MapKeysIterator[Object, nullable Object], MapIterator[Object, nullable Object]) */
-void abstract_collection__MapKeysIterator__iterator_61d(val* self, val* p0) {
+/* method abstract_collection#MapKeysIterator#original_iterator= for (self: MapKeysIterator[Object, nullable Object], MapIterator[Object, nullable Object]) */
+void abstract_collection__MapKeysIterator__original_iterator_61d(val* self, val* p0) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 const char* var_class_name;
-/* Covariant cast for argument 0 (iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapKeysIterator#0, MapKeysIterator#1] */
-/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapKeysIterator#0, MapKeysIterator#1] */
+/* Covariant cast for argument 0 (original_iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
+/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapIteratorabstract_collection__MapKeysIterator_FT0abstract_collection__MapKeysIterator_FT1];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -1959,28 +1388,66 @@ var = 0;
 } else {
 var = p0->type->type_table[cltype] == idtype;
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[MapKeysIterator#0, MapKeysIterator#1]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 384);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[K, V]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 554);
+show_backtrace(1);
 }
-self->attrs[COLOR_abstract_collection__MapKeysIterator___64diterator].val = p0; /* @iterator on <self:MapKeysIterator[Object, nullable Object]> */
+self->attrs[COLOR_abstract_collection__MapKeysIterator___original_iterator].val = p0; /* _original_iterator on <self:MapKeysIterator[Object, nullable Object]> */
 RET_LABEL:;
 }
-/* method abstract_collection#MapKeysIterator#iterator= for (self: Object, MapIterator[Object, nullable Object]) */
-void VIRTUAL_abstract_collection__MapKeysIterator__iterator_61d(val* self, val* p0) {
-abstract_collection__MapKeysIterator__iterator_61d(self, p0);
+/* method abstract_collection#MapKeysIterator#original_iterator= for (self: Object, MapIterator[Object, nullable Object]) */
+void VIRTUAL_abstract_collection__MapKeysIterator__original_iterator_61d(val* self, val* p0) {
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+{ /* Inline abstract_collection#MapKeysIterator#original_iterator= (self,p0) on <self:Object(MapKeysIterator[Object, nullable Object])> */
+/* Covariant cast for argument 0 (original_iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
+/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapIteratorabstract_collection__MapKeysIterator_FT0abstract_collection__MapKeysIterator_FT1];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= p0->type->table_size) {
+var = 0;
+} else {
+var = p0->type->type_table[cltype] == idtype;
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[K, V]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 554);
+show_backtrace(1);
+}
+self->attrs[COLOR_abstract_collection__MapKeysIterator___original_iterator].val = p0; /* _original_iterator on <self:Object(MapKeysIterator[Object, nullable Object])> */
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#MapKeysIterator#is_ok for (self: MapKeysIterator[Object, nullable Object]): Bool */
 short int abstract_collection__MapKeysIterator__is_ok(val* self) {
 short int var /* : Bool */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-short int var2 /* : Bool */;
-var1 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__MapKeysIterator__iterator]))(self) /* iterator on <self:MapKeysIterator[Object, nullable Object]>*/;
-var2 = ((short int (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__is_ok]))(var1) /* is_ok on <var1:MapIterator[Object, nullable Object]>*/;
-var = var2;
+val* var3 /* : MapIterator[Object, nullable Object] */;
+short int var4 /* : Bool */;
+{
+{ /* Inline abstract_collection#MapKeysIterator#original_iterator (self) on <self:MapKeysIterator[Object, nullable Object]> */
+var3 = self->attrs[COLOR_abstract_collection__MapKeysIterator___original_iterator].val; /* _original_iterator on <self:MapKeysIterator[Object, nullable Object]> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 554);
+show_backtrace(1);
+}
+var1 = var3;
+RET_LABEL2:(void)0;
+}
+}
+{
+var4 = ((short int (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__is_ok]))(var1) /* is_ok on <var1:MapIterator[Object, nullable Object]>*/;
+}
+var = var4;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -1997,23 +1464,51 @@ return var;
 /* method abstract_collection#MapKeysIterator#next for (self: MapKeysIterator[Object, nullable Object]) */
 void abstract_collection__MapKeysIterator__next(val* self) {
 val* var /* : MapIterator[Object, nullable Object] */;
-var = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__MapKeysIterator__iterator]))(self) /* iterator on <self:MapKeysIterator[Object, nullable Object]>*/;
+val* var2 /* : MapIterator[Object, nullable Object] */;
+{
+{ /* Inline abstract_collection#MapKeysIterator#original_iterator (self) on <self:MapKeysIterator[Object, nullable Object]> */
+var2 = self->attrs[COLOR_abstract_collection__MapKeysIterator___original_iterator].val; /* _original_iterator on <self:MapKeysIterator[Object, nullable Object]> */
+if (unlikely(var2 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 554);
+show_backtrace(1);
+}
+var = var2;
+RET_LABEL1:(void)0;
+}
+}
+{
 ((void (*)(val*))(var->class->vft[COLOR_abstract_collection__MapIterator__next]))(var) /* next on <var:MapIterator[Object, nullable Object]>*/;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#MapKeysIterator#next for (self: Object) */
 void VIRTUAL_abstract_collection__MapKeysIterator__next(val* self) {
-abstract_collection__MapKeysIterator__next(self);
+abstract_collection__MapKeysIterator__next(self); /* Direct call abstract_collection#MapKeysIterator#next on <self:Object(MapKeysIterator[Object, nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#MapKeysIterator#item for (self: MapKeysIterator[Object, nullable Object]): Object */
 val* abstract_collection__MapKeysIterator__item(val* self) {
 val* var /* : Object */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-val* var2 /* : Object */;
-var1 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__MapKeysIterator__iterator]))(self) /* iterator on <self:MapKeysIterator[Object, nullable Object]>*/;
-var2 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__key]))(var1) /* key on <var1:MapIterator[Object, nullable Object]>*/;
-var = var2;
+val* var3 /* : MapIterator[Object, nullable Object] */;
+val* var4 /* : Object */;
+{
+{ /* Inline abstract_collection#MapKeysIterator#original_iterator (self) on <self:MapKeysIterator[Object, nullable Object]> */
+var3 = self->attrs[COLOR_abstract_collection__MapKeysIterator___original_iterator].val; /* _original_iterator on <self:MapKeysIterator[Object, nullable Object]> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 554);
+show_backtrace(1);
+}
+var1 = var3;
+RET_LABEL2:(void)0;
+}
+}
+{
+var4 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__key]))(var1) /* key on <var1:MapIterator[Object, nullable Object]>*/;
+}
+var = var4;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2027,69 +1522,65 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapKeysIterator#init for (self: MapKeysIterator[Object, nullable Object], MapIterator[Object, nullable Object]) */
-void abstract_collection__MapKeysIterator__init(val* self, val* p0) {
-short int var /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-const char* var_class_name;
-/* Covariant cast for argument 0 (iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapKeysIterator#0, MapKeysIterator#1] */
-/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapKeysIterator#0, MapKeysIterator#1] */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapIteratorabstract_collection__MapKeysIterator_FT0abstract_collection__MapKeysIterator_FT1];
-cltype = type_struct->color;
-idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
-var = 0;
-} else {
-var = p0->type->type_table[cltype] == idtype;
-}
-if (!var) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[MapKeysIterator#0, MapKeysIterator#1]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 381);
-exit(1);
+/* method abstract_collection#MapKeysIterator#init for (self: MapKeysIterator[Object, nullable Object]) */
+void abstract_collection__MapKeysIterator__init(val* self) {
+{
+((void (*)(val*))(self->class->vft[COLOR_abstract_collection__MapKeysIterator__init]))(self) /* init on <self:MapKeysIterator[Object, nullable Object]>*/;
 }
-self->attrs[COLOR_abstract_collection__MapKeysIterator___64diterator].val = p0; /* @iterator on <self:MapKeysIterator[Object, nullable Object]> */
 RET_LABEL:;
 }
-/* method abstract_collection#MapKeysIterator#init for (self: Object, MapIterator[Object, nullable Object]) */
-void VIRTUAL_abstract_collection__MapKeysIterator__init(val* self, val* p0) {
-abstract_collection__MapKeysIterator__init(self, p0);
+/* method abstract_collection#MapKeysIterator#init for (self: Object) */
+void VIRTUAL_abstract_collection__MapKeysIterator__init(val* self) {
+{ /* Inline abstract_collection#MapKeysIterator#init (self) on <self:Object(MapKeysIterator[Object, nullable Object])> */
+{
+((void (*)(val*))(self->class->vft[COLOR_abstract_collection__MapKeysIterator__init]))(self) /* init on <self:Object(MapKeysIterator[Object, nullable Object])>*/;
+}
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
-/* method abstract_collection#MapValuesIterator#iterator for (self: MapValuesIterator[Object, nullable Object]): MapIterator[Object, nullable Object] */
-val* abstract_collection__MapValuesIterator__iterator(val* self) {
+/* method abstract_collection#MapValuesIterator#original_iterator for (self: MapValuesIterator[Object, nullable Object]): MapIterator[Object, nullable Object] */
+val* abstract_collection__MapValuesIterator__original_iterator(val* self) {
 val* var /* : MapIterator[Object, nullable Object] */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-var1 = self->attrs[COLOR_abstract_collection__MapValuesIterator___64diterator].val; /* @iterator on <self:MapValuesIterator[Object, nullable Object]> */
-if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s", "Uninitialized attribute @iterator");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 395);
-exit(1);
+var1 = self->attrs[COLOR_abstract_collection__MapValuesIterator___original_iterator].val; /* _original_iterator on <self:MapValuesIterator[Object, nullable Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 565);
+show_backtrace(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapValuesIterator#iterator for (self: Object): MapIterator[Object, nullable Object] */
-val* VIRTUAL_abstract_collection__MapValuesIterator__iterator(val* self) {
+/* method abstract_collection#MapValuesIterator#original_iterator for (self: Object): MapIterator[Object, nullable Object] */
+val* VIRTUAL_abstract_collection__MapValuesIterator__original_iterator(val* self) {
 val* var /* : MapIterator[Object, nullable Object] */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-var1 = abstract_collection__MapValuesIterator__iterator(self);
+val* var3 /* : MapIterator[Object, nullable Object] */;
+{ /* Inline abstract_collection#MapValuesIterator#original_iterator (self) on <self:Object(MapValuesIterator[Object, nullable Object])> */
+var3 = self->attrs[COLOR_abstract_collection__MapValuesIterator___original_iterator].val; /* _original_iterator on <self:Object(MapValuesIterator[Object, nullable Object])> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 565);
+show_backtrace(1);
+}
+var1 = var3;
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapValuesIterator#iterator= for (self: MapValuesIterator[Object, nullable Object], MapIterator[Object, nullable Object]) */
-void abstract_collection__MapValuesIterator__iterator_61d(val* self, val* p0) {
+/* method abstract_collection#MapValuesIterator#original_iterator= for (self: MapValuesIterator[Object, nullable Object], MapIterator[Object, nullable Object]) */
+void abstract_collection__MapValuesIterator__original_iterator_61d(val* self, val* p0) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 const char* var_class_name;
-/* Covariant cast for argument 0 (iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapValuesIterator#0, MapValuesIterator#1] */
-/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapValuesIterator#0, MapValuesIterator#1] */
+/* Covariant cast for argument 0 (original_iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
+/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapIteratorabstract_collection__MapValuesIterator_FT0abstract_collection__MapValuesIterator_FT1];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -2098,28 +1589,66 @@ var = 0;
 } else {
 var = p0->type->type_table[cltype] == idtype;
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[MapValuesIterator#0, MapValuesIterator#1]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 395);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[K, V]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 565);
+show_backtrace(1);
 }
-self->attrs[COLOR_abstract_collection__MapValuesIterator___64diterator].val = p0; /* @iterator on <self:MapValuesIterator[Object, nullable Object]> */
+self->attrs[COLOR_abstract_collection__MapValuesIterator___original_iterator].val = p0; /* _original_iterator on <self:MapValuesIterator[Object, nullable Object]> */
 RET_LABEL:;
 }
-/* method abstract_collection#MapValuesIterator#iterator= for (self: Object, MapIterator[Object, nullable Object]) */
-void VIRTUAL_abstract_collection__MapValuesIterator__iterator_61d(val* self, val* p0) {
-abstract_collection__MapValuesIterator__iterator_61d(self, p0);
+/* method abstract_collection#MapValuesIterator#original_iterator= for (self: Object, MapIterator[Object, nullable Object]) */
+void VIRTUAL_abstract_collection__MapValuesIterator__original_iterator_61d(val* self, val* p0) {
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+{ /* Inline abstract_collection#MapValuesIterator#original_iterator= (self,p0) on <self:Object(MapValuesIterator[Object, nullable Object])> */
+/* Covariant cast for argument 0 (original_iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
+/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[K, V] */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapIteratorabstract_collection__MapValuesIterator_FT0abstract_collection__MapValuesIterator_FT1];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= p0->type->table_size) {
+var = 0;
+} else {
+var = p0->type->type_table[cltype] == idtype;
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[K, V]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 565);
+show_backtrace(1);
+}
+self->attrs[COLOR_abstract_collection__MapValuesIterator___original_iterator].val = p0; /* _original_iterator on <self:Object(MapValuesIterator[Object, nullable Object])> */
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#MapValuesIterator#is_ok for (self: MapValuesIterator[Object, nullable Object]): Bool */
 short int abstract_collection__MapValuesIterator__is_ok(val* self) {
 short int var /* : Bool */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-short int var2 /* : Bool */;
-var1 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__MapValuesIterator__iterator]))(self) /* iterator on <self:MapValuesIterator[Object, nullable Object]>*/;
-var2 = ((short int (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__is_ok]))(var1) /* is_ok on <var1:MapIterator[Object, nullable Object]>*/;
-var = var2;
+val* var3 /* : MapIterator[Object, nullable Object] */;
+short int var4 /* : Bool */;
+{
+{ /* Inline abstract_collection#MapValuesIterator#original_iterator (self) on <self:MapValuesIterator[Object, nullable Object]> */
+var3 = self->attrs[COLOR_abstract_collection__MapValuesIterator___original_iterator].val; /* _original_iterator on <self:MapValuesIterator[Object, nullable Object]> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 565);
+show_backtrace(1);
+}
+var1 = var3;
+RET_LABEL2:(void)0;
+}
+}
+{
+var4 = ((short int (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__is_ok]))(var1) /* is_ok on <var1:MapIterator[Object, nullable Object]>*/;
+}
+var = var4;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2136,23 +1665,51 @@ return var;
 /* method abstract_collection#MapValuesIterator#next for (self: MapValuesIterator[Object, nullable Object]) */
 void abstract_collection__MapValuesIterator__next(val* self) {
 val* var /* : MapIterator[Object, nullable Object] */;
-var = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__MapValuesIterator__iterator]))(self) /* iterator on <self:MapValuesIterator[Object, nullable Object]>*/;
+val* var2 /* : MapIterator[Object, nullable Object] */;
+{
+{ /* Inline abstract_collection#MapValuesIterator#original_iterator (self) on <self:MapValuesIterator[Object, nullable Object]> */
+var2 = self->attrs[COLOR_abstract_collection__MapValuesIterator___original_iterator].val; /* _original_iterator on <self:MapValuesIterator[Object, nullable Object]> */
+if (unlikely(var2 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 565);
+show_backtrace(1);
+}
+var = var2;
+RET_LABEL1:(void)0;
+}
+}
+{
 ((void (*)(val*))(var->class->vft[COLOR_abstract_collection__MapIterator__next]))(var) /* next on <var:MapIterator[Object, nullable Object]>*/;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#MapValuesIterator#next for (self: Object) */
 void VIRTUAL_abstract_collection__MapValuesIterator__next(val* self) {
-abstract_collection__MapValuesIterator__next(self);
+abstract_collection__MapValuesIterator__next(self); /* Direct call abstract_collection#MapValuesIterator#next on <self:Object(MapValuesIterator[Object, nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#MapValuesIterator#item for (self: MapValuesIterator[Object, nullable Object]): nullable Object */
 val* abstract_collection__MapValuesIterator__item(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : MapIterator[Object, nullable Object] */;
-val* var2 /* : nullable Object */;
-var1 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__MapValuesIterator__iterator]))(self) /* iterator on <self:MapValuesIterator[Object, nullable Object]>*/;
-var2 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__item]))(var1) /* item on <var1:MapIterator[Object, nullable Object]>*/;
-var = var2;
+val* var3 /* : MapIterator[Object, nullable Object] */;
+val* var4 /* : nullable Object */;
+{
+{ /* Inline abstract_collection#MapValuesIterator#original_iterator (self) on <self:MapValuesIterator[Object, nullable Object]> */
+var3 = self->attrs[COLOR_abstract_collection__MapValuesIterator___original_iterator].val; /* _original_iterator on <self:MapValuesIterator[Object, nullable Object]> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _original_iterator");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 565);
+show_backtrace(1);
+}
+var1 = var3;
+RET_LABEL2:(void)0;
+}
+}
+{
+var4 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__MapIterator__item]))(var1) /* item on <var1:MapIterator[Object, nullable Object]>*/;
+}
+var = var4;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2166,35 +1723,21 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#MapValuesIterator#init for (self: MapValuesIterator[Object, nullable Object], MapIterator[Object, nullable Object]) */
-void abstract_collection__MapValuesIterator__init(val* self, val* p0) {
-short int var /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-const char* var_class_name;
-/* Covariant cast for argument 0 (iterator) <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapValuesIterator#0, MapValuesIterator#1] */
-/* <p0:MapIterator[Object, nullable Object]> isa MapIterator[MapValuesIterator#0, MapValuesIterator#1] */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapIteratorabstract_collection__MapValuesIterator_FT0abstract_collection__MapValuesIterator_FT1];
-cltype = type_struct->color;
-idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
-var = 0;
-} else {
-var = p0->type->type_table[cltype] == idtype;
-}
-if (!var) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapIterator[MapValuesIterator#0, MapValuesIterator#1]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 392);
-exit(1);
+/* method abstract_collection#MapValuesIterator#init for (self: MapValuesIterator[Object, nullable Object]) */
+void abstract_collection__MapValuesIterator__init(val* self) {
+{
+((void (*)(val*))(self->class->vft[COLOR_abstract_collection__MapValuesIterator__init]))(self) /* init on <self:MapValuesIterator[Object, nullable Object]>*/;
 }
-self->attrs[COLOR_abstract_collection__MapValuesIterator___64diterator].val = p0; /* @iterator on <self:MapValuesIterator[Object, nullable Object]> */
 RET_LABEL:;
 }
-/* method abstract_collection#MapValuesIterator#init for (self: Object, MapIterator[Object, nullable Object]) */
-void VIRTUAL_abstract_collection__MapValuesIterator__init(val* self, val* p0) {
-abstract_collection__MapValuesIterator__init(self, p0);
+/* method abstract_collection#MapValuesIterator#init for (self: Object) */
+void VIRTUAL_abstract_collection__MapValuesIterator__init(val* self) {
+{ /* Inline abstract_collection#MapValuesIterator#init (self) on <self:Object(MapValuesIterator[Object, nullable Object])> */
+{
+((void (*)(val*))(self->class->vft[COLOR_abstract_collection__MapValuesIterator__init]))(self) /* init on <self:Object(MapValuesIterator[Object, nullable Object])>*/;
+}
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#SequenceRead#first for (self: SequenceRead[nullable Object]): nullable Object */
@@ -2204,15 +1747,19 @@ short int var1 /* : Bool */;
 short int var2 /* : Bool */;
 long var3 /* : Int */;
 val* var4 /* : nullable Object */;
+{
 var1 = ((short int (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__is_empty]))(self) /* is_empty on <self:SequenceRead[nullable Object]>*/;
+}
 var2 = !var1;
-if (!var2) {
-fprintf(stderr, "Runtime error: %s", "Assert \'not_empty\' failed");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 411);
-exit(1);
+if (unlikely(!var2)) {
+PRINT_ERROR("Runtime error: %s", "Assert \'not_empty\' failed");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 590);
+show_backtrace(1);
 }
 var3 = 0;
+{
 var4 = ((val* (*)(val*, long))(self->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(self, var3) /* [] on <self:SequenceRead[nullable Object]>*/;
+}
 var = var4;
 goto RET_LABEL;
 RET_LABEL:;
@@ -2227,26 +1774,6 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#SequenceRead#[] for (self: SequenceRead[nullable Object], Int): nullable Object */
-val* abstract_collection__SequenceRead___91d_93d(val* self, long p0) {
-val* var /* : nullable Object */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "[]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 415);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#SequenceRead#[] for (self: Object, Int): nullable Object */
-val* VIRTUAL_abstract_collection__SequenceRead___91d_93d(val* self, long p0) {
-val* var /* : nullable Object */;
-val* var1 /* : nullable Object */;
-var1 = abstract_collection__SequenceRead___91d_93d(self, p0);
-var = var1;
-RET_LABEL:;
-return var;
-}
 /* method abstract_collection#SequenceRead#last for (self: SequenceRead[nullable Object]): nullable Object */
 val* abstract_collection__SequenceRead__last(val* self) {
 val* var /* : nullable Object */;
@@ -2255,25 +1782,46 @@ short int var2 /* : Bool */;
 long var3 /* : Int */;
 long var4 /* : Int */;
 long var5 /* : Int */;
-long var7 /* : Int */;
-val* var8 /* : nullable Object */;
+short int var7 /* : Bool */;
+int cltype;
+int idtype;
+const char* var_class_name;
+long var8 /* : Int */;
+val* var9 /* : nullable Object */;
+{
 var1 = ((short int (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__is_empty]))(self) /* is_empty on <self:SequenceRead[nullable Object]>*/;
+}
 var2 = !var1;
-if (!var2) {
-fprintf(stderr, "Runtime error: %s", "Assert \'not_empty\' failed");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 424);
-exit(1);
+if (unlikely(!var2)) {
+PRINT_ERROR("Runtime error: %s", "Assert \'not_empty\' failed");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 615);
+show_backtrace(1);
 }
+{
 var3 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:SequenceRead[nullable Object]>*/;
+}
 var4 = 1;
-{ /* Inline kernel#Int#- (var3,var4) */
-var7 = var3 - var4;
-var5 = var7;
+{
+{ /* Inline kernel#Int#- (var3,var4) on <var3:Int> */
+/* Covariant cast for argument 0 (i) <var4:Int> isa OTHER */
+/* <var4:Int> isa OTHER */
+var7 = 1; /* easy <var4:Int> isa OTHER*/
+if (unlikely(!var7)) {
+var_class_name = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 377);
+show_backtrace(1);
+}
+var8 = var3 - var4;
+var5 = var8;
 goto RET_LABEL6;
 RET_LABEL6:(void)0;
 }
-var8 = ((val* (*)(val*, long))(self->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(self, var5) /* [] on <self:SequenceRead[nullable Object]>*/;
-var = var8;
+}
+{
+var9 = ((val* (*)(val*, long))(self->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(self, var5) /* [] on <self:SequenceRead[nullable Object]>*/;
+}
+var = var9;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2297,17 +1845,167 @@ const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
 val* var_item /* var item: nullable Object */;
-val* var2 /* : Iterator[nullable Object] */;
+long var2 /* : Int */;
+long var3 /* : Int */;
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__SequenceRead_FT0];
+cltype = type_struct->color;
+idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var1 = is_nullable;
+} else {
+if(cltype >= p0->type->table_size) {
+var1 = 0;
+} else {
+var1 = p0->type->type_table[cltype] == idtype;
+}
+}
+if (unlikely(!var1)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 619);
+show_backtrace(1);
+}
+var_item = p0;
+var2 = 0;
+{
+var3 = ((long (*)(val*, val*, long))(self->class->vft[COLOR_abstract_collection__SequenceRead__index_of_from]))(self, var_item, var2) /* index_of_from on <self:SequenceRead[nullable Object]>*/;
+}
+var = var3;
+goto RET_LABEL;
+RET_LABEL:;
+return var;
+}
+/* method abstract_collection#SequenceRead#index_of for (self: Object, nullable Object): Int */
+long VIRTUAL_abstract_collection__SequenceRead__index_of(val* self, val* p0) {
+long var /* : Int */;
+long var1 /* : Int */;
+var1 = abstract_collection__SequenceRead__index_of(self, p0);
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method abstract_collection#SequenceRead#last_index_of for (self: SequenceRead[nullable Object], nullable Object): Int */
+long abstract_collection__SequenceRead__last_index_of(val* self, val* p0) {
+long var /* : Int */;
+short int var1 /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+short int is_nullable;
+const char* var_class_name;
+val* var_item /* var item: nullable Object */;
+long var2 /* : Int */;
+long var3 /* : Int */;
+long var4 /* : Int */;
+short int var6 /* : Bool */;
+int cltype7;
+int idtype8;
+const char* var_class_name9;
+long var10 /* : Int */;
+long var11 /* : Int */;
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__SequenceRead_FT0];
+cltype = type_struct->color;
+idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var1 = is_nullable;
+} else {
+if(cltype >= p0->type->table_size) {
+var1 = 0;
+} else {
+var1 = p0->type->type_table[cltype] == idtype;
+}
+}
+if (unlikely(!var1)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 628);
+show_backtrace(1);
+}
+var_item = p0;
+{
+var2 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:SequenceRead[nullable Object]>*/;
+}
+var3 = 1;
+{
+{ /* Inline kernel#Int#- (var2,var3) on <var2:Int> */
+/* Covariant cast for argument 0 (i) <var3:Int> isa OTHER */
+/* <var3:Int> isa OTHER */
+var6 = 1; /* easy <var3:Int> isa OTHER*/
+if (unlikely(!var6)) {
+var_class_name9 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name9);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 377);
+show_backtrace(1);
+}
+var10 = var2 - var3;
+var4 = var10;
+goto RET_LABEL5;
+RET_LABEL5:(void)0;
+}
+}
+{
+var11 = ((long (*)(val*, val*, long))(self->class->vft[COLOR_abstract_collection__SequenceRead__last_index_of_from]))(self, var_item, var4) /* last_index_of_from on <self:SequenceRead[nullable Object]>*/;
+}
+var = var11;
+goto RET_LABEL;
+RET_LABEL:;
+return var;
+}
+/* method abstract_collection#SequenceRead#last_index_of for (self: Object, nullable Object): Int */
+long VIRTUAL_abstract_collection__SequenceRead__last_index_of(val* self, val* p0) {
+long var /* : Int */;
+long var1 /* : Int */;
+var1 = abstract_collection__SequenceRead__last_index_of(self, p0);
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method abstract_collection#SequenceRead#index_of_from for (self: SequenceRead[nullable Object], nullable Object, Int): Int */
+long abstract_collection__SequenceRead__index_of_from(val* self, val* p0, long p1) {
+long var /* : Int */;
+short int var1 /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+short int is_nullable;
+const char* var_class_name;
+val* var_item /* var item: nullable Object */;
+long var_pos /* var pos: Int */;
+long var2 /* : Int */;
+long var_p /* var p: Int */;
+val* var3 /* : Iterator[nullable Object] */;
 val* var_i /* var i: IndexedIterator[nullable Object] */;
-short int var3 /* : Bool */;
-val* var4 /* : nullable Object */;
+short int var4 /* : Bool */;
 short int var5 /* : Bool */;
-long var6 /* : Int */;
-long var7 /* : Int */;
-long var8 /* : Int */;
-long var10 /* : Int */;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa SequenceRead#0 */
-/* <p0:nullable Object> isa SequenceRead#0 */
+short int var6 /* : Bool */;
+short int var8 /* : Bool */;
+int cltype9;
+int idtype10;
+const char* var_class_name11;
+short int var12 /* : Bool */;
+short int var_ /* var : Bool */;
+val* var13 /* : nullable Object */;
+short int var14 /* : Bool */;
+short int var15 /* : Bool */;
+long var16 /* : Int */;
+long var17 /* : Int */;
+long var18 /* : Int */;
+short int var20 /* : Bool */;
+int cltype21;
+int idtype22;
+const char* var_class_name23;
+long var24 /* : Int */;
+long var25 /* : Int */;
+long var26 /* : Int */;
+long var28 /* : Int */;
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__SequenceRead_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -2321,71 +2019,266 @@ var1 = 0;
 var1 = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var1) {
+if (unlikely(!var1)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "SequenceRead#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 428);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 637);
+show_backtrace(1);
 }
 var_item = p0;
-var2 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:SequenceRead[nullable Object]>*/;
-var_i = var2;
+var_pos = p1;
+var2 = 0;
+var_p = var2;
+{
+var3 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:SequenceRead[nullable Object]>*/;
+}
+var_i = var3;
 for(;;) {
-var3 = ((short int (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_i) /* is_ok on <var_i:IndexedIterator[nullable Object]>*/;
-if (!var3) break;
-var4 = ((val* (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__item]))(var_i) /* item on <var_i:IndexedIterator[nullable Object]>*/;
-if (var4 == NULL) {
-var5 = (var_item == NULL);
+{
+var4 = ((short int (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_i) /* is_ok on <var_i:IndexedIterator[nullable Object]>*/;
+}
+if (var4){
+{
+{ /* Inline kernel#Int#>= (var_p,var_pos) on <var_p:Int> */
+/* Covariant cast for argument 0 (i) <var_pos:Int> isa OTHER */
+/* <var_pos:Int> isa OTHER */
+var8 = 1; /* easy <var_pos:Int> isa OTHER*/
+if (unlikely(!var8)) {
+var_class_name11 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name11);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 372);
+show_backtrace(1);
+}
+var12 = var_p >= var_pos;
+var6 = var12;
+goto RET_LABEL7;
+RET_LABEL7:(void)0;
+}
+}
+var_ = var6;
+if (var6){
+{
+var13 = ((val* (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__item]))(var_i) /* item on <var_i:IndexedIterator[nullable Object]>*/;
+}
+if (var13 == NULL) {
+var14 = (var_item == NULL);
+} else {
+var15 = ((short int (*)(val*, val*))(var13->class->vft[COLOR_kernel__Object___61d_61d]))(var13, var_item) /* == on <var13:nullable Object>*/;
+var14 = var15;
+}
+var5 = var14;
 } else {
-var5 = ((short int (*)(val*, val*))(var4->class->vft[COLOR_kernel__Object___61d_61d]))(var4, var_item) /* == on <var4:nullable Object>*/;
+var5 = var_;
 }
 if (var5){
-var6 = ((long (*)(val*))(var_i->class->vft[COLOR_abstract_collection__IndexedIterator__index]))(var_i) /* index on <var_i:IndexedIterator[nullable Object]>*/;
-var = var6;
+{
+var16 = ((long (*)(val*))(var_i->class->vft[COLOR_abstract_collection__IndexedIterator__index]))(var_i) /* index on <var_i:IndexedIterator[nullable Object]>*/;
+}
+var = var16;
 goto RET_LABEL;
 } else {
 }
+{
 ((void (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__next]))(var_i) /* next on <var_i:IndexedIterator[nullable Object]>*/;
-CONTINUE_label: (void)0;
+}
+var17 = 1;
+{
+{ /* Inline kernel#Int#+ (var_p,var17) on <var_p:Int> */
+/* Covariant cast for argument 0 (i) <var17:Int> isa OTHER */
+/* <var17:Int> isa OTHER */
+var20 = 1; /* easy <var17:Int> isa OTHER*/
+if (unlikely(!var20)) {
+var_class_name23 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name23);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var24 = var_p + var17;
+var18 = var24;
+goto RET_LABEL19;
+RET_LABEL19:(void)0;
+}
+}
+var_p = var18;
+} else {
+goto BREAK_label;
+}
 }
 BREAK_label: (void)0;
-var7 = 1;
-{ /* Inline kernel#Int#unary - (var7) */
-var10 = -var7;
-var8 = var10;
-goto RET_LABEL9;
-RET_LABEL9:(void)0;
+var25 = 1;
+{
+{ /* Inline kernel#Int#unary - (var25) on <var25:Int> */
+var28 = -var25;
+var26 = var28;
+goto RET_LABEL27;
+RET_LABEL27:(void)0;
 }
-var = var8;
+}
+var = var26;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#SequenceRead#index_of for (self: Object, nullable Object): Int */
-long VIRTUAL_abstract_collection__SequenceRead__index_of(val* self, val* p0) {
+/* method abstract_collection#SequenceRead#index_of_from for (self: Object, nullable Object, Int): Int */
+long VIRTUAL_abstract_collection__SequenceRead__index_of_from(val* self, val* p0, long p1) {
 long var /* : Int */;
 long var1 /* : Int */;
-var1 = abstract_collection__SequenceRead__index_of(self, p0);
+var1 = abstract_collection__SequenceRead__index_of_from(self, p0, p1);
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#SequenceRead#iterator for (self: SequenceRead[nullable Object]): IndexedIterator[nullable Object] */
-val* abstract_collection__SequenceRead__iterator(val* self) {
-val* var /* : IndexedIterator[nullable Object] */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "iterator", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 441);
-exit(1);
+/* method abstract_collection#SequenceRead#last_index_of_from for (self: SequenceRead[nullable Object], nullable Object, Int): Int */
+long abstract_collection__SequenceRead__last_index_of_from(val* self, val* p0, long p1) {
+long var /* : Int */;
+short int var1 /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+short int is_nullable;
+const char* var_class_name;
+val* var_item /* var item: nullable Object */;
+long var_pos /* var pos: Int */;
+long var2 /* : Int */;
+long var3 /* : Int */;
+long var5 /* : Int */;
+long var_res /* var res: Int */;
+long var6 /* : Int */;
+long var_p /* var p: Int */;
+val* var7 /* : Iterator[nullable Object] */;
+val* var_i /* var i: IndexedIterator[nullable Object] */;
+short int var8 /* : Bool */;
+short int var9 /* : Bool */;
+short int var11 /* : Bool */;
+int cltype12;
+int idtype13;
+const char* var_class_name14;
+short int var15 /* : Bool */;
+val* var16 /* : nullable Object */;
+short int var17 /* : Bool */;
+short int var18 /* : Bool */;
+long var19 /* : Int */;
+long var20 /* : Int */;
+short int var22 /* : Bool */;
+int cltype23;
+int idtype24;
+const char* var_class_name25;
+long var26 /* : Int */;
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__SequenceRead_FT0];
+cltype = type_struct->color;
+idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var1 = is_nullable;
+} else {
+if(cltype >= p0->type->table_size) {
+var1 = 0;
+} else {
+var1 = p0->type->type_table[cltype] == idtype;
+}
+}
+if (unlikely(!var1)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 657);
+show_backtrace(1);
+}
+var_item = p0;
+var_pos = p1;
+var2 = 1;
+{
+{ /* Inline kernel#Int#unary - (var2) on <var2:Int> */
+var5 = -var2;
+var3 = var5;
+goto RET_LABEL4;
+RET_LABEL4:(void)0;
+}
+}
+var_res = var3;
+var6 = 0;
+var_p = var6;
+{
+var7 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:SequenceRead[nullable Object]>*/;
+}
+var_i = var7;
+for(;;) {
+{
+var8 = ((short int (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_i) /* is_ok on <var_i:IndexedIterator[nullable Object]>*/;
+}
+if (var8){
+{
+{ /* Inline kernel#Int#> (var_p,var_pos) on <var_p:Int> */
+/* Covariant cast for argument 0 (i) <var_pos:Int> isa OTHER */
+/* <var_pos:Int> isa OTHER */
+var11 = 1; /* easy <var_pos:Int> isa OTHER*/
+if (unlikely(!var11)) {
+var_class_name14 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name14);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 373);
+show_backtrace(1);
+}
+var15 = var_p > var_pos;
+var9 = var15;
+goto RET_LABEL10;
+RET_LABEL10:(void)0;
+}
+}
+if (var9){
+goto BREAK_label;
+} else {
+}
+{
+var16 = ((val* (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__item]))(var_i) /* item on <var_i:IndexedIterator[nullable Object]>*/;
+}
+if (var16 == NULL) {
+var17 = (var_item == NULL);
+} else {
+var18 = ((short int (*)(val*, val*))(var16->class->vft[COLOR_kernel__Object___61d_61d]))(var16, var_item) /* == on <var16:nullable Object>*/;
+var17 = var18;
+}
+if (var17){
+var_res = var_p;
+} else {
+}
+{
+((void (*)(val*))(var_i->class->vft[COLOR_abstract_collection__Iterator__next]))(var_i) /* next on <var_i:IndexedIterator[nullable Object]>*/;
+}
+var19 = 1;
+{
+{ /* Inline kernel#Int#+ (var_p,var19) on <var_p:Int> */
+/* Covariant cast for argument 0 (i) <var19:Int> isa OTHER */
+/* <var19:Int> isa OTHER */
+var22 = 1; /* easy <var19:Int> isa OTHER*/
+if (unlikely(!var22)) {
+var_class_name25 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name25);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var26 = var_p + var19;
+var20 = var26;
+goto RET_LABEL21;
+RET_LABEL21:(void)0;
+}
+}
+var_p = var20;
+} else {
+goto BREAK_label;
+}
+}
+BREAK_label: (void)0;
+var = var_res;
+goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#SequenceRead#iterator for (self: Object): Iterator[nullable Object] */
-val* VIRTUAL_abstract_collection__SequenceRead__iterator(val* self) {
-val* var /* : Iterator[nullable Object] */;
-val* var1 /* : IndexedIterator[nullable Object] */;
-var1 = abstract_collection__SequenceRead__iterator(self);
+/* method abstract_collection#SequenceRead#last_index_of_from for (self: Object, nullable Object, Int): Int */
+long VIRTUAL_abstract_collection__SequenceRead__last_index_of_from(val* self, val* p0, long p1) {
+long var /* : Int */;
+long var1 /* : Int */;
+var1 = abstract_collection__SequenceRead__last_index_of_from(self, p0, p1);
 var = var1;
 RET_LABEL:;
 return var;
@@ -2403,25 +2296,31 @@ long var4 /* : Int */;
 long var_l /* var l: Int */;
 long var5 /* : Int */;
 short int var6 /* : Bool */;
-short int var8 /* : Bool */;
+short int var7 /* : Bool */;
 short int var9 /* : Bool */;
 short int var10 /* : Bool */;
-long var11 /* : Int */;
+short int var11 /* : Bool */;
+long var12 /* : Int */;
 long var_i /* var i: Int */;
-short int var12 /* : Bool */;
-short int var14 /* : Bool */;
-int cltype15;
-int idtype16;
+short int var13 /* : Bool */;
+short int var15 /* : Bool */;
+int cltype16;
+int idtype17;
 const char* var_class_name;
-short int var17 /* : Bool */;
-val* var18 /* : nullable Object */;
+short int var18 /* : Bool */;
 val* var19 /* : nullable Object */;
-short int var20 /* : Bool */;
+val* var20 /* : nullable Object */;
 short int var21 /* : Bool */;
-long var22 /* : Int */;
-long var23 /* : Int */;
+short int var22 /* : Bool */;
+short int var23 /* : Bool */;
+long var24 /* : Int */;
 long var25 /* : Int */;
-short int var26 /* : Bool */;
+short int var27 /* : Bool */;
+int cltype28;
+int idtype29;
+const char* var_class_name30;
+long var31 /* : Int */;
+short int var32 /* : Bool */;
 var_o = p0;
 /* <var_o:nullable Object> isa SequenceRead[nullable Object] */
 cltype = type_abstract_collection__SequenceReadnullable_kernel__Object.color;
@@ -2442,67 +2341,94 @@ var = var3;
 goto RET_LABEL;
 } else {
 }
+{
 var4 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:SequenceRead[nullable Object]>*/;
+}
 var_l = var4;
+{
 var5 = ((long (*)(val*))(var_o->class->vft[COLOR_abstract_collection__Collection__length]))(var_o) /* length on <var_o:nullable Object(SequenceRead[nullable Object])>*/;
-{ /* Inline kernel#Int#!= (var5,var_l) */
-var8 = var5 == var_l;
-var9 = !var8;
-var6 = var9;
-goto RET_LABEL7;
-RET_LABEL7:(void)0;
+}
+{
+{ /* Inline kernel#Int#!= (var5,var_l) on <var5:Int> */
+var9 = var5 == var_l;
+var10 = !var9;
+var7 = var10;
+goto RET_LABEL8;
+RET_LABEL8:(void)0;
+}
+var6 = var7;
 }
 if (var6){
-var10 = 0;
-var = var10;
+var11 = 0;
+var = var11;
 goto RET_LABEL;
 } else {
 }
-var11 = 0;
-var_i = var11;
+var12 = 0;
+var_i = var12;
 for(;;) {
-{ /* Inline kernel#Int#< (var_i,var_l) */
+{
+{ /* Inline kernel#Int#< (var_i,var_l) on <var_i:Int> */
 /* Covariant cast for argument 0 (i) <var_l:Int> isa OTHER */
 /* <var_l:Int> isa OTHER */
-var14 = 1; /* easy <var_l:Int> isa OTHER*/
-if (!var14) {
+var15 = 1; /* easy <var_l:Int> isa OTHER*/
+if (unlikely(!var15)) {
 var_class_name = type_kernel__Int.name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/kernel.nit", 261);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 371);
+show_backtrace(1);
+}
+var18 = var_i < var_l;
+var13 = var18;
+goto RET_LABEL14;
+RET_LABEL14:(void)0;
 }
-var17 = var_i < var_l;
-var12 = var17;
-goto RET_LABEL13;
-RET_LABEL13:(void)0;
 }
-if (!var12) break;
-var18 = ((val* (*)(val*, long))(self->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(self, var_i) /* [] on <self:SequenceRead[nullable Object]>*/;
-var19 = ((val* (*)(val*, long))(var_o->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(var_o, var_i) /* [] on <var_o:nullable Object(SequenceRead[nullable Object])>*/;
-if (var18 == NULL) {
-var20 = (var19 != NULL);
+if (var13){
+{
+var19 = ((val* (*)(val*, long))(self->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(self, var_i) /* [] on <self:SequenceRead[nullable Object]>*/;
+}
+{
+var20 = ((val* (*)(val*, long))(var_o->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(var_o, var_i) /* [] on <var_o:nullable Object(SequenceRead[nullable Object])>*/;
+}
+if (var19 == NULL) {
+var21 = (var20 != NULL);
 } else {
-var20 = ((short int (*)(val*, val*))(var18->class->vft[COLOR_kernel__Object___33d_61d]))(var18, var19) /* != on <var18:nullable Object>*/;
+var22 = ((short int (*)(val*, val*))(var19->class->vft[COLOR_kernel__Object___33d_61d]))(var19, var20) /* != on <var19:nullable Object>*/;
+var21 = var22;
 }
-if (var20){
-var21 = 0;
-var = var21;
+if (var21){
+var23 = 0;
+var = var23;
 goto RET_LABEL;
 } else {
 }
-var22 = 1;
-{ /* Inline kernel#Int#+ (var_i,var22) */
-var25 = var_i + var22;
-var23 = var25;
-goto RET_LABEL24;
-RET_LABEL24:(void)0;
+var24 = 1;
+{
+{ /* Inline kernel#Int#+ (var_i,var24) on <var_i:Int> */
+/* Covariant cast for argument 0 (i) <var24:Int> isa OTHER */
+/* <var24:Int> isa OTHER */
+var27 = 1; /* easy <var24:Int> isa OTHER*/
+if (unlikely(!var27)) {
+var_class_name30 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name30);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var31 = var_i + var24;
+var25 = var31;
+goto RET_LABEL26;
+RET_LABEL26:(void)0;
+}
+}
+var_i = var25;
+} else {
+goto BREAK_label;
 }
-var_i = var23;
-CONTINUE_label: (void)0;
 }
 BREAK_label: (void)0;
-var26 = 1;
-var = var26;
+var32 = 1;
+var = var32;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2520,34 +2446,168 @@ return var;
 long abstract_collection__SequenceRead__hash(val* self) {
 long var /* : Int */;
 long var1 /* : Int */;
+long var2 /* : Int */;
+long var3 /* : Int */;
+short int var5 /* : Bool */;
+int cltype;
+int idtype;
+const char* var_class_name;
+long var6 /* : Int */;
 long var_res /* var res: Int */;
-val* var2 /* : Iterator[nullable Object] */;
-short int var3 /* : Bool */;
-val* var4 /* : nullable Object */;
+val* var_ /* var : SequenceRead[nullable Object] */;
+val* var7 /* : Iterator[nullable Object] */;
+val* var_8 /* var : IndexedIterator[nullable Object] */;
+short int var9 /* : Bool */;
+val* var10 /* : nullable Object */;
 val* var_e /* var e: nullable Object */;
-long var5 /* : Int */;
-long var6 /* : Int */;
-long var8 /* : Int */;
-var1 = 0;
-var_res = var1;
-var2 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:SequenceRead[nullable Object]>*/;
+long var11 /* : Int */;
+long var12 /* : Int */;
+short int var14 /* : Bool */;
+int cltype15;
+int idtype16;
+const char* var_class_name17;
+long var18 /* : Int */;
+long var19 /* : Int */;
+long var20 /* : Int */;
+short int var22 /* : Bool */;
+int cltype23;
+int idtype24;
+const char* var_class_name25;
+long var26 /* : Int */;
+val* var27 /* : null */;
+short int var28 /* : Bool */;
+short int var29 /* : Bool */;
+long var30 /* : Int */;
+long var31 /* : Int */;
+short int var33 /* : Bool */;
+int cltype34;
+int idtype35;
+const char* var_class_name36;
+long var37 /* : Int */;
+var1 = 17;
+{
+var2 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:SequenceRead[nullable Object]>*/;
+}
+{
+{ /* Inline kernel#Int#+ (var1,var2) on <var1:Int> */
+/* Covariant cast for argument 0 (i) <var2:Int> isa OTHER */
+/* <var2:Int> isa OTHER */
+var5 = 1; /* easy <var2:Int> isa OTHER*/
+if (unlikely(!var5)) {
+var_class_name = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var6 = var1 + var2;
+var3 = var6;
+goto RET_LABEL4;
+RET_LABEL4:(void)0;
+}
+}
+var_res = var3;
+var_ = self;
+{
+var7 = ((val* (*)(val*))(var_->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:SequenceRead[nullable Object]>*/;
+}
+var_8 = var7;
 for(;;) {
-var3 = ((short int (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var2) /* is_ok on <var2:Iterator[nullable Object]>*/;
-if(!var3) break;
-var4 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__item]))(var2) /* item on <var2:Iterator[nullable Object]>*/;
-var_e = var4;
-var5 = kernel__Int__hash(var_res);
-{ /* Inline kernel#Int#+ (var_res,var5) */
-var8 = var_res + var5;
-var6 = var8;
-goto RET_LABEL7;
-RET_LABEL7:(void)0;
+{
+var9 = ((short int (*)(val*))(var_8->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_8) /* is_ok on <var_8:IndexedIterator[nullable Object]>*/;
+}
+if (var9){
+{
+var10 = ((val* (*)(val*))(var_8->class->vft[COLOR_abstract_collection__Iterator__item]))(var_8) /* item on <var_8:IndexedIterator[nullable Object]>*/;
+}
+var_e = var10;
+var11 = 3;
+{
+{ /* Inline kernel#Int#* (var_res,var11) on <var_res:Int> */
+/* Covariant cast for argument 0 (i) <var11:Int> isa OTHER */
+/* <var11:Int> isa OTHER */
+var14 = 1; /* easy <var11:Int> isa OTHER*/
+if (unlikely(!var14)) {
+var_class_name17 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name17);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 378);
+show_backtrace(1);
+}
+var18 = var_res * var11;
+var12 = var18;
+goto RET_LABEL13;
+RET_LABEL13:(void)0;
+}
+}
+var19 = 2;
+{
+{ /* Inline kernel#Int#/ (var12,var19) on <var12:Int> */
+/* Covariant cast for argument 0 (i) <var19:Int> isa OTHER */
+/* <var19:Int> isa OTHER */
+var22 = 1; /* easy <var19:Int> isa OTHER*/
+if (unlikely(!var22)) {
+var_class_name25 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name25);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 379);
+show_backtrace(1);
+}
+var26 = var12 / var19;
+var20 = var26;
+goto RET_LABEL21;
+RET_LABEL21:(void)0;
+}
+}
+var_res = var20;
+var27 = NULL;
+if (var_e == NULL) {
+var28 = 0; /* is null */
+} else {
+var28 = 1; /* arg is null and recv is not */
+}
+if (0) {
+var29 = ((short int (*)(val*, val*))(var_e->class->vft[COLOR_kernel__Object___33d_61d]))(var_e, var27) /* != on <var_e:nullable Object>*/;
+var28 = var29;
+}
+if (var28){
+if (var_e == NULL) {
+PRINT_ERROR("Runtime error: %s", "Receiver is null");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 709);
+show_backtrace(1);
+} else {
+var30 = ((long (*)(val*))(var_e->class->vft[COLOR_kernel__Object__hash]))(var_e) /* hash on <var_e:nullable Object>*/;
+}
+{
+{ /* Inline kernel#Int#+ (var_res,var30) on <var_res:Int> */
+/* Covariant cast for argument 0 (i) <var30:Int> isa OTHER */
+/* <var30:Int> isa OTHER */
+var33 = 1; /* easy <var30:Int> isa OTHER*/
+if (unlikely(!var33)) {
+var_class_name36 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name36);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var37 = var_res + var30;
+var31 = var37;
+goto RET_LABEL32;
+RET_LABEL32:(void)0;
+}
+}
+var_res = var31;
+} else {
+}
+{
+((void (*)(val*))(var_8->class->vft[COLOR_abstract_collection__Iterator__next]))(var_8) /* next on <var_8:IndexedIterator[nullable Object]>*/;
+}
+} else {
+goto BREAK_label;
 }
-var_res = var6;
-CONTINUE_label: (void)0;
-((void (*)(val*))(var2->class->vft[COLOR_abstract_collection__Iterator__next]))(var2) /* next on <var2:Iterator[nullable Object]>*/;
 }
 BREAK_label: (void)0;
+{
+{ /* Inline abstract_collection#Iterator#finish (var_8) on <var_8:IndexedIterator[nullable Object]> */
+RET_LABEL38:(void)0;
+}
+}
 var = var_res;
 goto RET_LABEL;
 RET_LABEL:;
@@ -2562,49 +2622,106 @@ var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Sequence#first= for (self: Sequence[nullable Object], nullable Object) */
-void abstract_collection__Sequence__first_61d(val* self, val* p0) {
-short int var /* : Bool */;
+/* method abstract_collection#SequenceRead#iterator_from for (self: SequenceRead[nullable Object], Int): IndexedIterator[nullable Object] */
+val* abstract_collection__SequenceRead__iterator_from(val* self, long p0) {
+val* var /* : IndexedIterator[nullable Object] */;
+long var_pos /* var pos: Int */;
+val* var1 /* : Iterator[nullable Object] */;
+val* var_res /* var res: IndexedIterator[nullable Object] */;
+short int var2 /* : Bool */;
+long var3 /* : Int */;
+short int var4 /* : Bool */;
+short int var6 /* : Bool */;
 int cltype;
 int idtype;
-const struct type* type_struct;
-short int is_nullable;
 const char* var_class_name;
-val* var_item /* var item: nullable Object */;
-long var1 /* : Int */;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa Sequence#0 */
-/* <p0:nullable Object> isa Sequence#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Sequence_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-is_nullable = type_struct->is_nullable;
-if(p0 == NULL) {
-var = is_nullable;
-} else {
-if(cltype >= p0->type->table_size) {
-var = 0;
+short int var7 /* : Bool */;
+short int var_ /* var : Bool */;
+short int var8 /* : Bool */;
+long var9 /* : Int */;
+long var10 /* : Int */;
+short int var12 /* : Bool */;
+int cltype13;
+int idtype14;
+const char* var_class_name15;
+long var16 /* : Int */;
+var_pos = p0;
+{
+var1 = ((val* (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__iterator]))(self) /* iterator on <self:SequenceRead[nullable Object]>*/;
+}
+var_res = var1;
+for(;;) {
+var3 = 0;
+{
+{ /* Inline kernel#Int#> (var_pos,var3) on <var_pos:Int> */
+/* Covariant cast for argument 0 (i) <var3:Int> isa OTHER */
+/* <var3:Int> isa OTHER */
+var6 = 1; /* easy <var3:Int> isa OTHER*/
+if (unlikely(!var6)) {
+var_class_name = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 373);
+show_backtrace(1);
+}
+var7 = var_pos > var3;
+var4 = var7;
+goto RET_LABEL5;
+RET_LABEL5:(void)0;
+}
+}
+var_ = var4;
+if (var4){
+{
+var8 = ((short int (*)(val*))(var_res->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_res) /* is_ok on <var_res:IndexedIterator[nullable Object]>*/;
+}
+var2 = var8;
 } else {
-var = p0->type->type_table[cltype] == idtype;
+var2 = var_;
 }
+if (var2){
+{
+((void (*)(val*))(var_res->class->vft[COLOR_abstract_collection__Iterator__next]))(var_res) /* next on <var_res:IndexedIterator[nullable Object]>*/;
 }
-if (!var) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Sequence#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 472);
-exit(1);
+var9 = 1;
+{
+{ /* Inline kernel#Int#- (var_pos,var9) on <var_pos:Int> */
+/* Covariant cast for argument 0 (i) <var9:Int> isa OTHER */
+/* <var9:Int> isa OTHER */
+var12 = 1; /* easy <var9:Int> isa OTHER*/
+if (unlikely(!var12)) {
+var_class_name15 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name15);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 377);
+show_backtrace(1);
 }
-var_item = p0;
-var1 = 0;
-((void (*)(val*, long, val*))(self->class->vft[COLOR_abstract_collection__Sequence___91d_93d_61d]))(self, var1, var_item) /* []= on <self:Sequence[nullable Object]>*/;
+var16 = var_pos - var9;
+var10 = var16;
+goto RET_LABEL11;
+RET_LABEL11:(void)0;
+}
+}
+var_pos = var10;
+} else {
+goto BREAK_label;
+}
+}
+BREAK_label: (void)0;
+var = var_res;
+goto RET_LABEL;
 RET_LABEL:;
+return var;
 }
-/* method abstract_collection#Sequence#first= for (self: Object, nullable Object) */
-void VIRTUAL_abstract_collection__Sequence__first_61d(val* self, val* p0) {
-abstract_collection__Sequence__first_61d(self, p0);
+/* method abstract_collection#SequenceRead#iterator_from for (self: Object, Int): IndexedIterator[nullable Object] */
+val* VIRTUAL_abstract_collection__SequenceRead__iterator_from(val* self, long p0) {
+val* var /* : IndexedIterator[nullable Object] */;
+val* var1 /* : IndexedIterator[nullable Object] */;
+var1 = abstract_collection__SequenceRead__iterator_from(self, p0);
+var = var1;
 RET_LABEL:;
+return var;
 }
-/* method abstract_collection#Sequence#last= for (self: Sequence[nullable Object], nullable Object) */
-void abstract_collection__Sequence__last_61d(val* self, val* p0) {
+/* method abstract_collection#Sequence#first= for (self: Sequence[nullable Object], nullable Object) */
+void abstract_collection__Sequence__first_61d(val* self, val* p0) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
@@ -2613,20 +2730,8 @@ short int is_nullable;
 const char* var_class_name;
 val* var_item /* var item: nullable Object */;
 long var1 /* : Int */;
-long var_l /* var l: Int */;
-long var2 /* : Int */;
-short int var3 /* : Bool */;
-short int var5 /* : Bool */;
-int cltype6;
-int idtype7;
-const char* var_class_name8;
-short int var9 /* : Bool */;
-long var10 /* : Int */;
-long var11 /* : Int */;
-long var13 /* : Int */;
-long var14 /* : Int */;
-/* Covariant cast for argument 0 (item) <p0:nullable Object> isa Sequence#0 */
-/* <p0:nullable Object> isa Sequence#0 */
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Sequence_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -2640,49 +2745,22 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Sequence#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 477);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 757);
+show_backtrace(1);
 }
 var_item = p0;
-var1 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Sequence[nullable Object]>*/;
-var_l = var1;
-var2 = 0;
-{ /* Inline kernel#Int#> (var_l,var2) */
-/* Covariant cast for argument 0 (i) <var2:Int> isa OTHER */
-/* <var2:Int> isa OTHER */
-var5 = 1; /* easy <var2:Int> isa OTHER*/
-if (!var5) {
-var_class_name8 = type_kernel__Int.name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name8);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/kernel.nit", 263);
-exit(1);
-}
-var9 = var_l > var2;
-var3 = var9;
-goto RET_LABEL4;
-RET_LABEL4:(void)0;
-}
-if (var3){
-var10 = 1;
-{ /* Inline kernel#Int#- (var_l,var10) */
-var13 = var_l - var10;
-var11 = var13;
-goto RET_LABEL12;
-RET_LABEL12:(void)0;
-}
-((void (*)(val*, long, val*))(self->class->vft[COLOR_abstract_collection__Sequence___91d_93d_61d]))(self, var11, var_item) /* []= on <self:Sequence[nullable Object]>*/;
-} else {
-var14 = 0;
-((void (*)(val*, long, val*))(self->class->vft[COLOR_abstract_collection__Sequence___91d_93d_61d]))(self, var14, var_item) /* []= on <self:Sequence[nullable Object]>*/;
+var1 = 0;
+{
+((void (*)(val*, long, val*))(self->class->vft[COLOR_abstract_collection__Sequence___91d_93d_61d]))(self, var1, var_item) /* []= on <self:Sequence[nullable Object]>*/;
 }
 RET_LABEL:;
 }
-/* method abstract_collection#Sequence#last= for (self: Object, nullable Object) */
-void VIRTUAL_abstract_collection__Sequence__last_61d(val* self, val* p0) {
-abstract_collection__Sequence__last_61d(self, p0);
+/* method abstract_collection#Sequence#first= for (self: Object, nullable Object) */
+void VIRTUAL_abstract_collection__Sequence__first_61d(val* self, val* p0) {
+abstract_collection__Sequence__first_61d(self, p0); /* Direct call abstract_collection#Sequence#first= on <self:Object(Sequence[nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#Sequence#add for (self: Sequence[nullable Object], nullable Object) */
@@ -2694,8 +2772,8 @@ const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
 val* var_e /* var e: nullable Object */;
-/* Covariant cast for argument 0 (e) <p0:nullable Object> isa SimpleCollection#0 */
-/* <p0:nullable Object> isa SimpleCollection#0 */
+/* Covariant cast for argument 0 (e) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__SimpleCollection_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -2709,60 +2787,21 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "SimpleCollection#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 489);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 788);
+show_backtrace(1);
 }
 var_e = p0;
+{
 ((void (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Sequence__push]))(self, var_e) /* push on <self:Sequence[nullable Object]>*/;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#Sequence#add for (self: Object, nullable Object) */
 void VIRTUAL_abstract_collection__Sequence__add(val* self, val* p0) {
-abstract_collection__Sequence__add(self, p0);
-RET_LABEL:;
-}
-/* method abstract_collection#Sequence#push for (self: Sequence[nullable Object], nullable Object) */
-void abstract_collection__Sequence__push(val* self, val* p0) {
-short int var /* : Bool */;
-int cltype;
-int idtype;
-const struct type* type_struct;
-short int is_nullable;
-const char* var_class_name;
-const char* var_class_name1;
-/* Covariant cast for argument 0 (e) <p0:nullable Object> isa Sequence#0 */
-/* <p0:nullable Object> isa Sequence#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Sequence_FT0];
-cltype = type_struct->color;
-idtype = type_struct->id;
-is_nullable = type_struct->is_nullable;
-if(p0 == NULL) {
-var = is_nullable;
-} else {
-if(cltype >= p0->type->table_size) {
-var = 0;
-} else {
-var = p0->type->type_table[cltype] == idtype;
-}
-}
-if (!var) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Sequence#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 492);
-exit(1);
-}
-var_class_name1 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "push", var_class_name1);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 492);
-exit(1);
-RET_LABEL:;
-}
-/* method abstract_collection#Sequence#push for (self: Object, nullable Object) */
-void VIRTUAL_abstract_collection__Sequence__push(val* self, val* p0) {
-abstract_collection__Sequence__push(self, p0);
+abstract_collection__Sequence__add(self, p0); /* Direct call abstract_collection#Sequence#add on <self:Object(Sequence[nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#Sequence#append for (self: Sequence[nullable Object], Collection[nullable Object]) */
@@ -2773,12 +2812,8 @@ int idtype;
 const struct type* type_struct;
 const char* var_class_name;
 val* var_coll /* var coll: Collection[nullable Object] */;
-val* var1 /* : Iterator[nullable Object] */;
-short int var2 /* : Bool */;
-val* var3 /* : nullable Object */;
-val* var_i /* var i: nullable Object */;
-/* Covariant cast for argument 0 (coll) <p0:Collection[nullable Object]> isa Collection[Sequence#0] */
-/* <p0:Collection[nullable Object]> isa Collection[Sequence#0] */
+/* Covariant cast for argument 0 (coll) <p0:Collection[nullable Object]> isa Collection[E] */
+/* <p0:Collection[nullable Object]> isa Collection[E] */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collectionabstract_collection__Sequence_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -2787,29 +2822,21 @@ var = 0;
 } else {
 var = p0->type->type_table[cltype] == idtype;
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[Sequence#0]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 495);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 799);
+show_backtrace(1);
 }
 var_coll = p0;
-var1 = ((val* (*)(val*))(var_coll->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_coll) /* iterator on <var_coll:Collection[nullable Object]>*/;
-for(;;) {
-var2 = ((short int (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var1) /* is_ok on <var1:Iterator[nullable Object]>*/;
-if(!var2) break;
-var3 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__item]))(var1) /* item on <var1:Iterator[nullable Object]>*/;
-var_i = var3;
-((void (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__Sequence__push]))(self, var_i) /* push on <self:Sequence[nullable Object]>*/;
-CONTINUE_label: (void)0;
-((void (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__next]))(var1) /* next on <var1:Iterator[nullable Object]>*/;
+{
+abstract_collection__SimpleCollection__add_all(self, var_coll); /* Direct call abstract_collection#SimpleCollection#add_all on <self:Sequence[nullable Object]>*/
 }
-BREAK_label: (void)0;
 RET_LABEL:;
 }
 /* method abstract_collection#Sequence#append for (self: Object, Collection[nullable Object]) */
 void VIRTUAL_abstract_collection__Sequence__append(val* self, val* p0) {
-abstract_collection__Sequence__append(self, p0);
+abstract_collection__Sequence__append(self, p0); /* Direct call abstract_collection#Sequence#append on <self:Object(Sequence[nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#Sequence#pop for (self: Sequence[nullable Object]): nullable Object */
@@ -2817,9 +2844,9 @@ val* abstract_collection__Sequence__pop(val* self) {
 val* var /* : nullable Object */;
 const char* var_class_name;
 var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "pop", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 498);
-exit(1);
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "pop", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 808);
+show_backtrace(1);
 RET_LABEL:;
 return var;
 }
@@ -2827,22 +2854,66 @@ return var;
 val* VIRTUAL_abstract_collection__Sequence__pop(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = abstract_collection__Sequence__pop(self);
+const char* var_class_name;
+{ /* Inline abstract_collection#Sequence#pop (self) on <self:Object(Sequence[nullable Object])> */
+var_class_name = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "pop", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 808);
+show_backtrace(1);
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
-return var;
+return var;
+}
+/* method abstract_collection#Sequence#unshift for (self: Sequence[nullable Object], nullable Object) */
+void abstract_collection__Sequence__unshift(val* self, val* p0) {
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+short int is_nullable;
+const char* var_class_name;
+const char* var_class_name1;
+/* Covariant cast for argument 0 (e) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Sequence_FT0];
+cltype = type_struct->color;
+idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var = is_nullable;
+} else {
+if(cltype >= p0->type->table_size) {
+var = 0;
+} else {
+var = p0->type->type_table[cltype] == idtype;
+}
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 818);
+show_backtrace(1);
+}
+var_class_name1 = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "unshift", var_class_name1);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 818);
+show_backtrace(1);
+RET_LABEL:;
 }
-/* method abstract_collection#Sequence#unshift for (self: Sequence[nullable Object], nullable Object) */
-void abstract_collection__Sequence__unshift(val* self, val* p0) {
+/* method abstract_collection#Sequence#unshift for (self: Object, nullable Object) */
+void VIRTUAL_abstract_collection__Sequence__unshift(val* self, val* p0) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
-const char* var_class_name1;
-/* Covariant cast for argument 0 (e) <p0:nullable Object> isa Sequence#0 */
-/* <p0:nullable Object> isa Sequence#0 */
+const char* var_class_name2;
+{ /* Inline abstract_collection#Sequence#unshift (self,p0) on <self:Object(Sequence[nullable Object])> */
+/* Covariant cast for argument 0 (e) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Sequence_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -2856,21 +2927,55 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Sequence#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 501);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 818);
+show_backtrace(1);
+}
+var_class_name2 = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "unshift", var_class_name2);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 818);
+show_backtrace(1);
+RET_LABEL1:(void)0;
 }
-var_class_name1 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "unshift", var_class_name1);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 501);
-exit(1);
 RET_LABEL:;
 }
-/* method abstract_collection#Sequence#unshift for (self: Object, nullable Object) */
-void VIRTUAL_abstract_collection__Sequence__unshift(val* self, val* p0) {
-abstract_collection__Sequence__unshift(self, p0);
+/* method abstract_collection#Sequence#prepend for (self: Sequence[nullable Object], Collection[nullable Object]) */
+void abstract_collection__Sequence__prepend(val* self, val* p0) {
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+val* var_coll /* var coll: Collection[nullable Object] */;
+long var1 /* : Int */;
+/* Covariant cast for argument 0 (coll) <p0:Collection[nullable Object]> isa Collection[E] */
+/* <p0:Collection[nullable Object]> isa Collection[E] */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collectionabstract_collection__Sequence_FT0];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= p0->type->table_size) {
+var = 0;
+} else {
+var = p0->type->type_table[cltype] == idtype;
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 826);
+show_backtrace(1);
+}
+var_coll = p0;
+var1 = 0;
+{
+((void (*)(val*, val*, long))(self->class->vft[COLOR_abstract_collection__Sequence__insert_all]))(self, var_coll, var1) /* insert_all on <self:Sequence[nullable Object]>*/;
+}
+RET_LABEL:;
+}
+/* method abstract_collection#Sequence#prepend for (self: Object, Collection[nullable Object]) */
+void VIRTUAL_abstract_collection__Sequence__prepend(val* self, val* p0) {
+abstract_collection__Sequence__prepend(self, p0); /* Direct call abstract_collection#Sequence#prepend on <self:Object(Sequence[nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#Sequence#shift for (self: Sequence[nullable Object]): nullable Object */
@@ -2878,9 +2983,9 @@ val* abstract_collection__Sequence__shift(val* self) {
 val* var /* : nullable Object */;
 const char* var_class_name;
 var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "shift", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 504);
-exit(1);
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "shift", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 835);
+show_backtrace(1);
 RET_LABEL:;
 return var;
 }
@@ -2888,13 +2993,20 @@ return var;
 val* VIRTUAL_abstract_collection__Sequence__shift(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = abstract_collection__Sequence__shift(self);
+const char* var_class_name;
+{ /* Inline abstract_collection#Sequence#shift (self) on <self:Object(Sequence[nullable Object])> */
+var_class_name = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "shift", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 835);
+show_backtrace(1);
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#Sequence#[]= for (self: Sequence[nullable Object], Int, nullable Object) */
-void abstract_collection__Sequence___91d_93d_61d(val* self, long p0, val* p1) {
+/* method abstract_collection#Sequence#insert for (self: Sequence[nullable Object], nullable Object, Int) */
+void abstract_collection__Sequence__insert(val* self, val* p0, long p1) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
@@ -2902,169 +3014,298 @@ const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
 const char* var_class_name1;
-/* Covariant cast for argument 1 (item) <p1:nullable Object> isa Sequence#0 */
-/* <p1:nullable Object> isa Sequence#0 */
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Sequence_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
 is_nullable = type_struct->is_nullable;
-if(p1 == NULL) {
+if(p0 == NULL) {
 var = is_nullable;
 } else {
-if(cltype >= p1->type->table_size) {
+if(cltype >= p0->type->table_size) {
 var = 0;
 } else {
-var = p1->type->type_table[cltype] == idtype;
+var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
-var_class_name = p1 == NULL ? "null" : p1->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Sequence#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 508);
-exit(1);
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 861);
+show_backtrace(1);
 }
 var_class_name1 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "[]=", var_class_name1);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 508);
-exit(1);
-RET_LABEL:;
-}
-/* method abstract_collection#Sequence#[]= for (self: Object, Int, nullable Object) */
-void VIRTUAL_abstract_collection__Sequence___91d_93d_61d(val* self, long p0, val* p1) {
-abstract_collection__Sequence___91d_93d_61d(self, p0, p1);
-RET_LABEL:;
-}
-/* method abstract_collection#Sequence#remove_at for (self: Sequence[nullable Object], Int) */
-void abstract_collection__Sequence__remove_at(val* self, long p0) {
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "remove_at", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 511);
-exit(1);
-RET_LABEL:;
-}
-/* method abstract_collection#Sequence#remove_at for (self: Object, Int) */
-void VIRTUAL_abstract_collection__Sequence__remove_at(val* self, long p0) {
-abstract_collection__Sequence__remove_at(self, p0);
-RET_LABEL:;
-}
-/* method abstract_collection#IndexedIterator#index for (self: IndexedIterator[nullable Object]): Int */
-long abstract_collection__IndexedIterator__index(val* self) {
-long var /* : Int */;
-const char* var_class_name;
-var_class_name = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "index", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 518);
-exit(1);
-RET_LABEL:;
-return var;
-}
-/* method abstract_collection#IndexedIterator#index for (self: Object): Int */
-long VIRTUAL_abstract_collection__IndexedIterator__index(val* self) {
-long var /* : Int */;
-long var1 /* : Int */;
-var1 = abstract_collection__IndexedIterator__index(self);
-var = var1;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "insert", var_class_name1);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 861);
+show_backtrace(1);
 RET_LABEL:;
-return var;
 }
-/* method abstract_collection#CoupleMap#couple_at for (self: CoupleMap[Object, nullable Object], Object): nullable Couple[Object, nullable Object] */
-val* abstract_collection__CoupleMap__couple_at(val* self, val* p0) {
-val* var /* : nullable Couple[Object, nullable Object] */;
-short int var1 /* : Bool */;
+/* method abstract_collection#Sequence#insert for (self: Object, nullable Object, Int) */
+void VIRTUAL_abstract_collection__Sequence__insert(val* self, val* p0, long p1) {
+short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
+short int is_nullable;
 const char* var_class_name;
 const char* var_class_name2;
-/* Covariant cast for argument 0 (key) <p0:Object> isa CoupleMap#0 */
-/* <p0:Object> isa CoupleMap#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__CoupleMap_FT0];
+{ /* Inline abstract_collection#Sequence#insert (self,p0,p1) on <self:Object(Sequence[nullable Object])> */
+/* Covariant cast for argument 0 (item) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Sequence_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var = is_nullable;
+} else {
 if(cltype >= p0->type->table_size) {
-var1 = 0;
+var = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var = p0->type->type_table[cltype] == idtype;
+}
 }
-if (!var1) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "CoupleMap#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 525);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 861);
+show_backtrace(1);
 }
 var_class_name2 = self == NULL ? "null" : self->type->name;
-fprintf(stderr, "Runtime error: Abstract method `%s` called on `%s`", "couple_at", var_class_name2);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 525);
-exit(1);
-RET_LABEL:;
-return var;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "insert", var_class_name2);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 861);
+show_backtrace(1);
+RET_LABEL1:(void)0;
 }
-/* method abstract_collection#CoupleMap#couple_at for (self: Object, Object): nullable Couple[Object, nullable Object] */
-val* VIRTUAL_abstract_collection__CoupleMap__couple_at(val* self, val* p0) {
-val* var /* : nullable Couple[Object, nullable Object] */;
-val* var1 /* : nullable Couple[Object, nullable Object] */;
-var1 = abstract_collection__CoupleMap__couple_at(self, p0);
-var = var1;
 RET_LABEL:;
-return var;
 }
-/* method abstract_collection#CoupleMap#[] for (self: CoupleMap[Object, nullable Object], Object): nullable Object */
-val* abstract_collection__CoupleMap___91d_93d(val* self, val* p0) {
-val* var /* : nullable Object */;
-short int var1 /* : Bool */;
+/* method abstract_collection#Sequence#insert_all for (self: Sequence[nullable Object], Collection[nullable Object], Int) */
+void abstract_collection__Sequence__insert_all(val* self, val* p0, long p1) {
+short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 const char* var_class_name;
-val* var_key /* var key: Object */;
-val* var2 /* : nullable Couple[Object, nullable Object] */;
-val* var_c /* var c: nullable Couple[Object, nullable Object] */;
-val* var3 /* : null */;
-short int var4 /* : Bool */;
-val* var5 /* : nullable Object */;
-/* Covariant cast for argument 0 (key) <p0:Object> isa MapRead#0 */
-/* <p0:Object> isa MapRead#0 */
-type_struct = self->type->resolution_table->types[COLOR_abstract_collection__MapRead_FT0];
+val* var_coll /* var coll: Collection[nullable Object] */;
+long var_index /* var index: Int */;
+short int var1 /* : Bool */;
+long var2 /* : Int */;
+short int var3 /* : Bool */;
+short int var5 /* : Bool */;
+int cltype6;
+int idtype7;
+const char* var_class_name8;
+short int var9 /* : Bool */;
+short int var_ /* var : Bool */;
+long var10 /* : Int */;
+short int var11 /* : Bool */;
+short int var13 /* : Bool */;
+int cltype14;
+int idtype15;
+const char* var_class_name16;
+short int var17 /* : Bool */;
+long var18 /* : Int */;
+short int var19 /* : Bool */;
+short int var20 /* : Bool */;
+short int var22 /* : Bool */;
+val* var_23 /* var : Collection[nullable Object] */;
+val* var24 /* : Iterator[nullable Object] */;
+val* var_25 /* var : Iterator[nullable Object] */;
+short int var26 /* : Bool */;
+val* var27 /* : nullable Object */;
+val* var_c /* var c: nullable Object */;
+long var28 /* : Int */;
+long var29 /* : Int */;
+short int var31 /* : Bool */;
+int cltype32;
+int idtype33;
+const char* var_class_name34;
+long var35 /* : Int */;
+/* Covariant cast for argument 0 (coll) <p0:Collection[nullable Object]> isa Collection[E] */
+/* <p0:Collection[nullable Object]> isa Collection[E] */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Collectionabstract_collection__Sequence_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
 if(cltype >= p0->type->table_size) {
-var1 = 0;
+var = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var = p0->type->type_table[cltype] == idtype;
 }
-if (!var1) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "MapRead#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 529);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 871);
+show_backtrace(1);
 }
-var_key = p0;
-var2 = ((val* (*)(val*, val*))(self->class->vft[COLOR_abstract_collection__CoupleMap__couple_at]))(self, var_key) /* couple_at on <self:CoupleMap[Object, nullable Object]>*/;
-var_c = var2;
-var3 = NULL;
-if (var_c == NULL) {
-var4 = 1; /* is null */
+var_coll = p0;
+var_index = p1;
+var2 = 0;
+{
+{ /* Inline kernel#Int#>= (var_index,var2) on <var_index:Int> */
+/* Covariant cast for argument 0 (i) <var2:Int> isa OTHER */
+/* <var2:Int> isa OTHER */
+var5 = 1; /* easy <var2:Int> isa OTHER*/
+if (unlikely(!var5)) {
+var_class_name8 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name8);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 372);
+show_backtrace(1);
+}
+var9 = var_index >= var2;
+var3 = var9;
+goto RET_LABEL4;
+RET_LABEL4:(void)0;
+}
+}
+var_ = var3;
+if (var3){
+{
+var10 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Sequence[nullable Object]>*/;
+}
+{
+{ /* Inline kernel#Int#< (var_index,var10) on <var_index:Int> */
+/* Covariant cast for argument 0 (i) <var10:Int> isa OTHER */
+/* <var10:Int> isa OTHER */
+var13 = 1; /* easy <var10:Int> isa OTHER*/
+if (unlikely(!var13)) {
+var_class_name16 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name16);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 371);
+show_backtrace(1);
+}
+var17 = var_index < var10;
+var11 = var17;
+goto RET_LABEL12;
+RET_LABEL12:(void)0;
+}
+}
+var1 = var11;
 } else {
-var4 = 0; /* arg is null but recv is not */
+var1 = var_;
+}
+if (unlikely(!var1)) {
+PRINT_ERROR("Runtime error: %s", "Assert failed");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 881);
+show_backtrace(1);
+}
+{
+var18 = ((long (*)(val*))(self->class->vft[COLOR_abstract_collection__Collection__length]))(self) /* length on <self:Sequence[nullable Object]>*/;
+}
+{
+{ /* Inline kernel#Int#== (var_index,var18) on <var_index:Int> */
+var22 = var_index == var18;
+var20 = var22;
+goto RET_LABEL21;
+RET_LABEL21:(void)0;
+}
+var19 = var20;
+}
+if (var19){
+{
+abstract_collection__SimpleCollection__add_all(self, var_coll); /* Direct call abstract_collection#SimpleCollection#add_all on <self:Sequence[nullable Object]>*/
 }
-if (var4){
-fprintf(stderr, "Runtime error: %s", "Aborted");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 533);
-exit(1);
 } else {
-var5 = ((val* (*)(val*))(var_c->class->vft[COLOR_abstract_collection__Couple__second]))(var_c) /* second on <var_c:nullable Couple[Object, nullable Object](Couple[Object, nullable Object])>*/;
-var = var5;
-goto RET_LABEL;
 }
+var_23 = var_coll;
+{
+var24 = ((val* (*)(val*))(var_23->class->vft[COLOR_abstract_collection__Collection__iterator]))(var_23) /* iterator on <var_23:Collection[nullable Object]>*/;
+}
+var_25 = var24;
+for(;;) {
+{
+var26 = ((short int (*)(val*))(var_25->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var_25) /* is_ok on <var_25:Iterator[nullable Object]>*/;
+}
+if (var26){
+{
+var27 = ((val* (*)(val*))(var_25->class->vft[COLOR_abstract_collection__Iterator__item]))(var_25) /* item on <var_25:Iterator[nullable Object]>*/;
+}
+var_c = var27;
+{
+((void (*)(val*, val*, long))(self->class->vft[COLOR_abstract_collection__Sequence__insert]))(self, var_c, var_index) /* insert on <self:Sequence[nullable Object]>*/;
+}
+var28 = 1;
+{
+{ /* Inline kernel#Int#+ (var_index,var28) on <var_index:Int> */
+/* Covariant cast for argument 0 (i) <var28:Int> isa OTHER */
+/* <var28:Int> isa OTHER */
+var31 = 1; /* easy <var28:Int> isa OTHER*/
+if (unlikely(!var31)) {
+var_class_name34 = type_kernel__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name34);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/kernel.nit", 374);
+show_backtrace(1);
+}
+var35 = var_index + var28;
+var29 = var35;
+goto RET_LABEL30;
+RET_LABEL30:(void)0;
+}
+}
+var_index = var29;
+{
+((void (*)(val*))(var_25->class->vft[COLOR_abstract_collection__Iterator__next]))(var_25) /* next on <var_25:Iterator[nullable Object]>*/;
+}
+} else {
+goto BREAK_label;
+}
+}
+BREAK_label: (void)0;
+{
+{ /* Inline abstract_collection#Iterator#finish (var_25) on <var_25:Iterator[nullable Object]> */
+RET_LABEL36:(void)0;
+}
+}
+RET_LABEL:;
+}
+/* method abstract_collection#Sequence#insert_all for (self: Object, Collection[nullable Object], Int) */
+void VIRTUAL_abstract_collection__Sequence__insert_all(val* self, val* p0, long p1) {
+abstract_collection__Sequence__insert_all(self, p0, p1); /* Direct call abstract_collection#Sequence#insert_all on <self:Object(Sequence[nullable Object])>*/
+RET_LABEL:;
+}
+/* method abstract_collection#Sequence#remove_at for (self: Sequence[nullable Object], Int) */
+void abstract_collection__Sequence__remove_at(val* self, long p0) {
+const char* var_class_name;
+var_class_name = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "remove_at", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 891);
+show_backtrace(1);
+RET_LABEL:;
+}
+/* method abstract_collection#Sequence#remove_at for (self: Object, Int) */
+void VIRTUAL_abstract_collection__Sequence__remove_at(val* self, long p0) {
+const char* var_class_name;
+{ /* Inline abstract_collection#Sequence#remove_at (self,p0) on <self:Object(Sequence[nullable Object])> */
+var_class_name = self == NULL ? "null" : self->type->name;
+PRINT_ERROR("Runtime error: Abstract method `%s` called on `%s`", "remove_at", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 891);
+show_backtrace(1);
+RET_LABEL1:(void)0;
+}
+RET_LABEL:;
+}
+/* method abstract_collection#CoupleMap#iterator for (self: CoupleMap[Object, nullable Object]): MapIterator[Object, nullable Object] */
+val* abstract_collection__CoupleMap__iterator(val* self) {
+val* var /* : MapIterator[Object, nullable Object] */;
+val* var1 /* : CoupleMapIterator[Object, nullable Object] */;
+val* var2 /* : Iterator[Couple[Object, nullable Object]] */;
+var1 = NEW_abstract_collection__CoupleMapIterator(self->type->resolution_table->types[COLOR_abstract_collection__CoupleMapIteratorabstract_collection__CoupleMap_FT0abstract_collection__CoupleMap_FT1]);
+{
+var2 = array__ArrayMap__couple_iterator(self);
+}
+{
+abstract_collection__CoupleMapIterator__init(var1, var2); /* Direct call abstract_collection#CoupleMapIterator#init on <var1:CoupleMapIterator[Object, nullable Object]>*/
+}
+var = var1;
+goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method abstract_collection#CoupleMap#[] for (self: Object, Object): nullable Object */
-val* VIRTUAL_abstract_collection__CoupleMap___91d_93d(val* self, val* p0) {
-val* var /* : nullable Object */;
-val* var1 /* : nullable Object */;
-var1 = abstract_collection__CoupleMap___91d_93d(self, p0);
+/* method abstract_collection#CoupleMap#iterator for (self: Object): MapIterator[Object, nullable Object] */
+val* VIRTUAL_abstract_collection__CoupleMap__iterator(val* self) {
+val* var /* : MapIterator[Object, nullable Object] */;
+val* var1 /* : MapIterator[Object, nullable Object] */;
+var1 = abstract_collection__CoupleMap__iterator(self);
 var = var1;
 RET_LABEL:;
 return var;
@@ -3075,14 +3316,23 @@ val* var /* : nullable Object */;
 val* var1 /* : Iterator[Couple[Object, nullable Object]] */;
 val* var2 /* : nullable Object */;
 val* var3 /* : nullable Object */;
+val* var5 /* : nullable Object */;
 var1 = self->attrs[COLOR_abstract_collection__CoupleMapIterator___iter].val; /* _iter on <self:CoupleMapIterator[Object, nullable Object]> */
-if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _iter");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 545);
-exit(1);
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _iter");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 939);
+show_backtrace(1);
 }
+{
 var2 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__item]))(var1) /* item on <var1:Iterator[Couple[Object, nullable Object]]>*/;
-var3 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Couple__second]))(var2) /* second on <var2:nullable Object(Couple[Object, nullable Object])>*/;
+}
+{
+{ /* Inline abstract_collection#Couple#second (var2) on <var2:nullable Object(Couple[Object, nullable Object])> */
+var5 = var2->attrs[COLOR_abstract_collection__Couple___second].val; /* _second on <var2:nullable Object(Couple[Object, nullable Object])> */
+var3 = var5;
+RET_LABEL4:(void)0;
+}
+}
 var = var3;
 goto RET_LABEL;
 RET_LABEL:;
@@ -3103,14 +3353,23 @@ val* var /* : Object */;
 val* var1 /* : Iterator[Couple[Object, nullable Object]] */;
 val* var2 /* : nullable Object */;
 val* var3 /* : nullable Object */;
+val* var5 /* : nullable Object */;
 var1 = self->attrs[COLOR_abstract_collection__CoupleMapIterator___iter].val; /* _iter on <self:CoupleMapIterator[Object, nullable Object]> */
-if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _iter");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 549);
-exit(1);
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _iter");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 943);
+show_backtrace(1);
 }
+{
 var2 = ((val* (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__item]))(var1) /* item on <var1:Iterator[Couple[Object, nullable Object]]>*/;
-var3 = ((val* (*)(val*))(var2->class->vft[COLOR_abstract_collection__Couple__first]))(var2) /* first on <var2:nullable Object(Couple[Object, nullable Object])>*/;
+}
+{
+{ /* Inline abstract_collection#Couple#first (var2) on <var2:nullable Object(Couple[Object, nullable Object])> */
+var5 = var2->attrs[COLOR_abstract_collection__Couple___first].val; /* _first on <var2:nullable Object(Couple[Object, nullable Object])> */
+var3 = var5;
+RET_LABEL4:(void)0;
+}
+}
 var = var3;
 goto RET_LABEL;
 RET_LABEL:;
@@ -3131,12 +3390,14 @@ short int var /* : Bool */;
 val* var1 /* : Iterator[Couple[Object, nullable Object]] */;
 short int var2 /* : Bool */;
 var1 = self->attrs[COLOR_abstract_collection__CoupleMapIterator___iter].val; /* _iter on <self:CoupleMapIterator[Object, nullable Object]> */
-if (var1 == NULL) {
-fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _iter");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 551);
-exit(1);
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _iter");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 945);
+show_backtrace(1);
 }
+{
 var2 = ((short int (*)(val*))(var1->class->vft[COLOR_abstract_collection__Iterator__is_ok]))(var1) /* is_ok on <var1:Iterator[Couple[Object, nullable Object]]>*/;
+}
 var = var2;
 goto RET_LABEL;
 RET_LABEL:;
@@ -3155,17 +3416,19 @@ return var;
 void abstract_collection__CoupleMapIterator__next(val* self) {
 val* var /* : Iterator[Couple[Object, nullable Object]] */;
 var = self->attrs[COLOR_abstract_collection__CoupleMapIterator___iter].val; /* _iter on <self:CoupleMapIterator[Object, nullable Object]> */
-if (var == NULL) {
-fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _iter");
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 555);
-exit(1);
+if (unlikely(var == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _iter");
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 949);
+show_backtrace(1);
 }
+{
 ((void (*)(val*))(var->class->vft[COLOR_abstract_collection__Iterator__next]))(var) /* next on <var:Iterator[Couple[Object, nullable Object]]>*/;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#CoupleMapIterator#next for (self: Object) */
 void VIRTUAL_abstract_collection__CoupleMapIterator__next(val* self) {
-abstract_collection__CoupleMapIterator__next(self);
+abstract_collection__CoupleMapIterator__next(self); /* Direct call abstract_collection#CoupleMapIterator#next on <self:Object(CoupleMapIterator[Object, nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#CoupleMapIterator#init for (self: CoupleMapIterator[Object, nullable Object], Iterator[Couple[Object, nullable Object]]) */
@@ -3176,8 +3439,8 @@ int idtype;
 const struct type* type_struct;
 const char* var_class_name;
 val* var_i /* var i: Iterator[Couple[Object, nullable Object]] */;
-/* Covariant cast for argument 0 (i) <p0:Iterator[Couple[Object, nullable Object]]> isa Iterator[Couple[CoupleMapIterator#0, CoupleMapIterator#1]] */
-/* <p0:Iterator[Couple[Object, nullable Object]]> isa Iterator[Couple[CoupleMapIterator#0, CoupleMapIterator#1]] */
+/* Covariant cast for argument 0 (i) <p0:Iterator[Couple[Object, nullable Object]]> isa Iterator[Couple[K, V]] */
+/* <p0:Iterator[Couple[Object, nullable Object]]> isa Iterator[Couple[K, V]] */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Iteratorabstract_collection__Coupleabstract_collection__CoupleMapIterator_FT0abstract_collection__CoupleMapIterator_FT1];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -3186,11 +3449,11 @@ var = 0;
 } else {
 var = p0->type->type_table[cltype] == idtype;
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Iterator[Couple[CoupleMapIterator#0, CoupleMapIterator#1]]", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 560);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Iterator[Couple[K, V]]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 954);
+show_backtrace(1);
 }
 var_i = p0;
 self->attrs[COLOR_abstract_collection__CoupleMapIterator___iter].val = var_i; /* _iter on <self:CoupleMapIterator[Object, nullable Object]> */
@@ -3198,7 +3461,7 @@ RET_LABEL:;
 }
 /* method abstract_collection#CoupleMapIterator#init for (self: Object, Iterator[Couple[Object, nullable Object]]) */
 void VIRTUAL_abstract_collection__CoupleMapIterator__init(val* self, val* p0) {
-abstract_collection__CoupleMapIterator__init(self, p0);
+abstract_collection__CoupleMapIterator__init(self, p0); /* Direct call abstract_collection#CoupleMapIterator#init on <self:Object(CoupleMapIterator[Object, nullable Object])>*/
 RET_LABEL:;
 }
 /* method abstract_collection#Couple#first for (self: Couple[nullable Object, nullable Object]): nullable Object */
@@ -3214,7 +3477,12 @@ return var;
 val* VIRTUAL_abstract_collection__Couple__first(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = abstract_collection__Couple__first(self);
+val* var3 /* : nullable Object */;
+{ /* Inline abstract_collection#Couple#first (self) on <self:Object(Couple[nullable Object, nullable Object])> */
+var3 = self->attrs[COLOR_abstract_collection__Couple___first].val; /* _first on <self:Object(Couple[nullable Object, nullable Object])> */
+var1 = var3;
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
 return var;
@@ -3227,8 +3495,8 @@ int idtype;
 const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
-/* Covariant cast for argument 0 (first) <p0:nullable Object> isa Couple#0 */
-/* <p0:nullable Object> isa Couple#0 */
+/* Covariant cast for argument 0 (first) <p0:nullable Object> isa F */
+/* <p0:nullable Object> isa F */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -3242,18 +3510,48 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Couple#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 568);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "F", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 962);
+show_backtrace(1);
 }
 self->attrs[COLOR_abstract_collection__Couple___first].val = p0; /* _first on <self:Couple[nullable Object, nullable Object]> */
 RET_LABEL:;
 }
 /* method abstract_collection#Couple#first= for (self: Object, nullable Object) */
 void VIRTUAL_abstract_collection__Couple__first_61d(val* self, val* p0) {
-abstract_collection__Couple__first_61d(self, p0);
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+short int is_nullable;
+const char* var_class_name;
+{ /* Inline abstract_collection#Couple#first= (self,p0) on <self:Object(Couple[nullable Object, nullable Object])> */
+/* Covariant cast for argument 0 (first) <p0:nullable Object> isa F */
+/* <p0:nullable Object> isa F */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT0];
+cltype = type_struct->color;
+idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var = is_nullable;
+} else {
+if(cltype >= p0->type->table_size) {
+var = 0;
+} else {
+var = p0->type->type_table[cltype] == idtype;
+}
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "F", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 962);
+show_backtrace(1);
+}
+self->attrs[COLOR_abstract_collection__Couple___first].val = p0; /* _first on <self:Object(Couple[nullable Object, nullable Object])> */
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#Couple#second for (self: Couple[nullable Object, nullable Object]): nullable Object */
@@ -3269,7 +3567,12 @@ return var;
 val* VIRTUAL_abstract_collection__Couple__second(val* self) {
 val* var /* : nullable Object */;
 val* var1 /* : nullable Object */;
-var1 = abstract_collection__Couple__second(self);
+val* var3 /* : nullable Object */;
+{ /* Inline abstract_collection#Couple#second (self) on <self:Object(Couple[nullable Object, nullable Object])> */
+var3 = self->attrs[COLOR_abstract_collection__Couple___second].val; /* _second on <self:Object(Couple[nullable Object, nullable Object])> */
+var1 = var3;
+RET_LABEL2:(void)0;
+}
 var = var1;
 RET_LABEL:;
 return var;
@@ -3282,8 +3585,8 @@ int idtype;
 const struct type* type_struct;
 short int is_nullable;
 const char* var_class_name;
-/* Covariant cast for argument 0 (second) <p0:nullable Object> isa Couple#1 */
-/* <p0:nullable Object> isa Couple#1 */
+/* Covariant cast for argument 0 (second) <p0:nullable Object> isa S */
+/* <p0:nullable Object> isa S */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT1];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -3297,18 +3600,48 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Couple#1", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 571);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "S", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 965);
+show_backtrace(1);
 }
 self->attrs[COLOR_abstract_collection__Couple___second].val = p0; /* _second on <self:Couple[nullable Object, nullable Object]> */
 RET_LABEL:;
 }
 /* method abstract_collection#Couple#second= for (self: Object, nullable Object) */
 void VIRTUAL_abstract_collection__Couple__second_61d(val* self, val* p0) {
-abstract_collection__Couple__second_61d(self, p0);
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+short int is_nullable;
+const char* var_class_name;
+{ /* Inline abstract_collection#Couple#second= (self,p0) on <self:Object(Couple[nullable Object, nullable Object])> */
+/* Covariant cast for argument 0 (second) <p0:nullable Object> isa S */
+/* <p0:nullable Object> isa S */
+type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT1];
+cltype = type_struct->color;
+idtype = type_struct->id;
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var = is_nullable;
+} else {
+if(cltype >= p0->type->table_size) {
+var = 0;
+} else {
+var = p0->type->type_table[cltype] == idtype;
+}
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : p0->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "S", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 965);
+show_backtrace(1);
+}
+self->attrs[COLOR_abstract_collection__Couple___second].val = p0; /* _second on <self:Object(Couple[nullable Object, nullable Object])> */
+RET_LABEL1:(void)0;
+}
 RET_LABEL:;
 }
 /* method abstract_collection#Couple#init for (self: Couple[nullable Object, nullable Object], nullable Object, nullable Object) */
@@ -3327,8 +3660,20 @@ short int is_nullable5;
 const char* var_class_name6;
 val* var_f /* var f: nullable Object */;
 val* var_s /* var s: nullable Object */;
-/* Covariant cast for argument 0 (f) <p0:nullable Object> isa Couple#0 */
-/* <p0:nullable Object> isa Couple#0 */
+short int var8 /* : Bool */;
+int cltype9;
+int idtype10;
+const struct type* type_struct11;
+short int is_nullable12;
+const char* var_class_name13;
+short int var15 /* : Bool */;
+int cltype16;
+int idtype17;
+const struct type* type_struct18;
+short int is_nullable19;
+const char* var_class_name20;
+/* Covariant cast for argument 0 (f) <p0:nullable Object> isa F */
+/* <p0:nullable Object> isa F */
 type_struct = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT0];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -3342,14 +3687,14 @@ var = 0;
 var = p0->type->type_table[cltype] == idtype;
 }
 }
-if (!var) {
+if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Couple#0", var_class_name);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 574);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "F", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 968);
+show_backtrace(1);
 }
-/* Covariant cast for argument 1 (s) <p1:nullable Object> isa Couple#1 */
-/* <p1:nullable Object> isa Couple#1 */
+/* Covariant cast for argument 1 (s) <p1:nullable Object> isa S */
+/* <p1:nullable Object> isa S */
 type_struct4 = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT1];
 cltype2 = type_struct4->color;
 idtype3 = type_struct4->id;
@@ -3363,20 +3708,72 @@ var1 = 0;
 var1 = p1->type->type_table[cltype2] == idtype3;
 }
 }
-if (!var1) {
+if (unlikely(!var1)) {
 var_class_name6 = p1 == NULL ? "null" : p1->type->name;
-fprintf(stderr, "Runtime error: Cast failed. Expected `%s`, got `%s`", "Couple#1", var_class_name6);
-fprintf(stderr, " (%s:%d)\n", "lib/standard/collection/abstract_collection.nit", 574);
-exit(1);
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "S", var_class_name6);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 968);
+show_backtrace(1);
 }
 var_f = p0;
 var_s = p1;
+{
+{ /* Inline abstract_collection#Couple#first= (self,var_f) on <self:Couple[nullable Object, nullable Object]> */
+/* Covariant cast for argument 0 (first) <var_f:nullable Object> isa F */
+/* <var_f:nullable Object> isa F */
+type_struct11 = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT0];
+cltype9 = type_struct11->color;
+idtype10 = type_struct11->id;
+is_nullable12 = type_struct11->is_nullable;
+if(var_f == NULL) {
+var8 = is_nullable12;
+} else {
+if(cltype9 >= var_f->type->table_size) {
+var8 = 0;
+} else {
+var8 = var_f->type->type_table[cltype9] == idtype10;
+}
+}
+if (unlikely(!var8)) {
+var_class_name13 = var_f == NULL ? "null" : var_f->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "F", var_class_name13);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 962);
+show_backtrace(1);
+}
 self->attrs[COLOR_abstract_collection__Couple___first].val = var_f; /* _first on <self:Couple[nullable Object, nullable Object]> */
+RET_LABEL7:(void)0;
+}
+}
+{
+{ /* Inline abstract_collection#Couple#second= (self,var_s) on <self:Couple[nullable Object, nullable Object]> */
+/* Covariant cast for argument 0 (second) <var_s:nullable Object> isa S */
+/* <var_s:nullable Object> isa S */
+type_struct18 = self->type->resolution_table->types[COLOR_abstract_collection__Couple_FT1];
+cltype16 = type_struct18->color;
+idtype17 = type_struct18->id;
+is_nullable19 = type_struct18->is_nullable;
+if(var_s == NULL) {
+var15 = is_nullable19;
+} else {
+if(cltype16 >= var_s->type->table_size) {
+var15 = 0;
+} else {
+var15 = var_s->type->type_table[cltype16] == idtype17;
+}
+}
+if (unlikely(!var15)) {
+var_class_name20 = var_s == NULL ? "null" : var_s->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "S", var_class_name20);
+PRINT_ERROR(" (%s:%d)\n", "../lib/standard/collection/abstract_collection.nit", 965);
+show_backtrace(1);
+}
 self->attrs[COLOR_abstract_collection__Couple___second].val = var_s; /* _second on <self:Couple[nullable Object, nullable Object]> */
+RET_LABEL14:(void)0;
+}
+}
 RET_LABEL:;
 }
 /* method abstract_collection#Couple#init for (self: Object, nullable Object, nullable Object) */
 void VIRTUAL_abstract_collection__Couple__init(val* self, val* p0, val* p1) {
-abstract_collection__Couple__init(self, p0, p1);
+abstract_collection__Couple__init(self, p0, p1); /* Direct call abstract_collection#Couple#init on <self:Object(Couple[nullable Object, nullable Object])>*/
 RET_LABEL:;
 }