regern c_src

[nit.git] / c_src / nit__coloring.sep.1.c

diff --git a/c_src/nit__coloring.sep.1.c b/c_src/nit__coloring.sep.1.c
index 9b49da5..1c3ef16 100644 (file)
--- a/c_src/nit__coloring.sep.1.c
+++ b/c_src/nit__coloring.sep.1.c
@@ -1,83 +1,83 @@
 #include "nit__coloring.sep.0.h"
-/* method coloring#POSetConflictGraph#core for (self: POSetConflictGraph[Object]): HashSet[Object] */
+/* method coloring#POSetConflictGraph#core for (self: POSetConflictGraph[nullable Object]): HashSet[nullable Object] */
 val* nit___nit__POSetConflictGraph___core(val* self) {
-val* var /* : HashSet[Object] */;
-val* var1 /* : HashSet[Object] */;
-var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[Object]> */
+val* var /* : HashSet[nullable Object] */;
+val* var1 /* : HashSet[nullable Object] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method coloring#POSetConflictGraph#border for (self: POSetConflictGraph[Object]): HashSet[Object] */
+/* method coloring#POSetConflictGraph#border for (self: POSetConflictGraph[nullable Object]): HashSet[nullable Object] */
 val* nit___nit__POSetConflictGraph___border(val* self) {
-val* var /* : HashSet[Object] */;
-val* var1 /* : HashSet[Object] */;
-var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[Object]> */
+val* var /* : HashSet[nullable Object] */;
+val* var1 /* : HashSet[nullable Object] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method coloring#POSetConflictGraph#crown for (self: POSetConflictGraph[Object]): HashSet[Object] */
+/* method coloring#POSetConflictGraph#crown for (self: POSetConflictGraph[nullable Object]): HashSet[nullable Object] */
 val* nit___nit__POSetConflictGraph___crown(val* self) {
-val* var /* : HashSet[Object] */;
-val* var1 /* : HashSet[Object] */;
-var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _crown on <self:POSetConflictGraph[Object]> */
+val* var /* : HashSet[nullable Object] */;
+val* var1 /* : HashSet[nullable Object] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _crown on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _crown");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 34);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method coloring#POSetConflictGraph#conflicts for (self: POSetConflictGraph[Object]): HashMap[Object, Set[Object]] */
+/* method coloring#POSetConflictGraph#conflicts for (self: POSetConflictGraph[nullable Object]): HashMap[nullable Object, Set[nullable Object]] */
 val* nit___nit__POSetConflictGraph___conflicts(val* self) {
-val* var /* : HashMap[Object, Set[Object]] */;
-val* var1 /* : HashMap[Object, Set[Object]] */;
-var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
+val* var /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var1 /* : HashMap[nullable Object, Set[nullable Object]] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method coloring#POSetConflictGraph#poset for (self: POSetConflictGraph[Object]): POSet[Object] */
+/* method coloring#POSetConflictGraph#poset for (self: POSetConflictGraph[nullable Object]): POSet[nullable Object] */
 val* nit___nit__POSetConflictGraph___poset(val* self) {
-val* var /* : POSet[Object] */;
-val* var1 /* : POSet[Object] */;
-var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[Object]> */
+val* var /* : POSet[nullable Object] */;
+val* var1 /* : POSet[nullable Object] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method coloring#POSetConflictGraph#poset= for (self: POSetConflictGraph[Object], POSet[Object]) */
+/* method coloring#POSetConflictGraph#poset= for (self: POSetConflictGraph[nullable Object], POSet[nullable Object]) */
 void nit___nit__POSetConflictGraph___poset_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 (poset) <p0:POSet[Object]> isa POSet[E] */
-/* <p0:POSet[Object]> isa POSet[E] */
+/* Covariant cast for argument 0 (poset) <p0:POSet[nullable Object]> isa POSet[E] */
+/* <p0:POSet[nullable Object]> isa POSet[E] */
 type_struct = self->type->resolution_table->types[COLOR_poset__POSet__nit__POSetConflictGraph___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
@@ -90,79 +90,177 @@ if (unlikely(!var)) {
 var_class_name = p0 == NULL ? "null" : p0->type->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "POSet[E]", var_class_name);
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
+}
+self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val = p0; /* _poset on <self:POSetConflictGraph[nullable Object]> */
+RET_LABEL:;
+}
+/* method coloring#POSetConflictGraph#order for (self: POSetConflictGraph[nullable Object]): Array[nullable Object] */
+val* nit___nit__POSetConflictGraph___order(val* self) {
+val* var /* : Array[nullable Object] */;
+val* var1 /* : Array[nullable Object] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___order].val; /* _order on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _order");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 51);
+fatal_exit(1);
+}
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetConflictGraph#order= for (self: POSetConflictGraph[nullable Object], Array[nullable Object]) */
+void nit___nit__POSetConflictGraph___order_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 (order) <p0:Array[nullable Object]> isa Array[E] */
+/* <p0:Array[nullable Object]> isa Array[E] */
+type_struct = self->type->resolution_table->types[COLOR_standard__Array__nit__POSetConflictGraph___35dE];
+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`", "Array[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 51);
+fatal_exit(1);
 }
-self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val = p0; /* _poset on <self:POSetConflictGraph[Object]> */
+self->attrs[COLOR_nit__coloring__POSetConflictGraph___order].val = p0; /* _order on <self:POSetConflictGraph[nullable Object]> */
 RET_LABEL:;
 }
-/* method coloring#POSetConflictGraph#init for (self: POSetConflictGraph[Object]) */
+/* method coloring#POSetConflictGraph#init for (self: POSetConflictGraph[nullable Object]) */
 void nit___nit__POSetConflictGraph___standard__kernel__Object__init(val* self) {
+val* var /* : POSet[nullable Object] */;
+val* var2 /* : POSet[nullable Object] */;
+val* var3 /* : POSet[nullable Object] */;
+val* var5 /* : POSet[nullable Object] */;
+val* var6 /* : Array[nullable Object] */;
+short int var8 /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+{
+nit___nit__POSetConflictGraph___extract_core(self); /* Direct call coloring#POSetConflictGraph#extract_core on <self:POSetConflictGraph[nullable Object]>*/
+}
+{
+nit___nit__POSetConflictGraph___extract_border(self); /* Direct call coloring#POSetConflictGraph#extract_border on <self:POSetConflictGraph[nullable Object]>*/
+}
+{
+nit___nit__POSetConflictGraph___extract_crown(self); /* Direct call coloring#POSetConflictGraph#extract_crown on <self:POSetConflictGraph[nullable Object]>*/
+}
 {
-nit___nit__POSetConflictGraph___extract_core(self); /* Direct call coloring#POSetConflictGraph#extract_core on <self:POSetConflictGraph[Object]>*/
+nit___nit__POSetConflictGraph___compute_conflicts(self); /* Direct call coloring#POSetConflictGraph#compute_conflicts on <self:POSetConflictGraph[nullable Object]>*/
+}
+{
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var2 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
+fatal_exit(1);
+}
+var = var2;
+RET_LABEL1:(void)0;
+}
 }
 {
-nit___nit__POSetConflictGraph___extract_border(self); /* Direct call coloring#POSetConflictGraph#extract_border on <self:POSetConflictGraph[Object]>*/
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var5 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
+fatal_exit(1);
+}
+var3 = var5;
+RET_LABEL4:(void)0;
+}
 }
 {
-nit___nit__POSetConflictGraph___extract_crown(self); /* Direct call coloring#POSetConflictGraph#extract_crown on <self:POSetConflictGraph[Object]>*/
+var6 = poset___poset__POSet___linearize(var, var3);
 }
 {
-nit___nit__POSetConflictGraph___compute_conflicts(self); /* Direct call coloring#POSetConflictGraph#compute_conflicts on <self:POSetConflictGraph[Object]>*/
+{ /* Inline coloring#POSetConflictGraph#order= (self,var6) on <self:POSetConflictGraph[nullable Object]> */
+/* Covariant cast for argument 0 (order) <var6:Array[nullable Object]> isa Array[E] */
+/* <var6:Array[nullable Object]> isa Array[E] */
+type_struct = self->type->resolution_table->types[COLOR_standard__Array__nit__POSetConflictGraph___35dE];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= var6->type->table_size) {
+var8 = 0;
+} else {
+var8 = var6->type->type_table[cltype] == idtype;
+}
+if (unlikely(!var8)) {
+var_class_name = var6 == NULL ? "null" : var6->type->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Array[E]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 51);
+fatal_exit(1);
+}
+self->attrs[COLOR_nit__coloring__POSetConflictGraph___order].val = var6; /* _order on <self:POSetConflictGraph[nullable Object]> */
+RET_LABEL7:(void)0;
+}
 }
 RET_LABEL:;
 }
-/* method coloring#POSetConflictGraph#extract_core for (self: POSetConflictGraph[Object]) */
+/* method coloring#POSetConflictGraph#extract_core for (self: POSetConflictGraph[nullable Object]) */
 void nit___nit__POSetConflictGraph___extract_core(val* self) {
-val* var /* : HashSet[Object] */;
-val* var2 /* : HashSet[Object] */;
-val* var3 /* : POSet[Object] */;
-val* var5 /* : POSet[Object] */;
-val* var_ /* var : POSet[Object] */;
+val* var /* : HashSet[nullable Object] */;
+val* var2 /* : HashSet[nullable Object] */;
+val* var3 /* : POSet[nullable Object] */;
+val* var5 /* : POSet[nullable Object] */;
+val* var_ /* var : POSet[nullable Object] */;
 val* var6 /* : Iterator[nullable Object] */;
-val* var_7 /* var : Iterator[Object] */;
+val* var_7 /* var : Iterator[nullable Object] */;
 short int var8 /* : Bool */;
 val* var9 /* : nullable Object */;
-val* var_e /* var e: Object */;
-val* var10 /* : POSet[Object] */;
-val* var12 /* : POSet[Object] */;
+val* var_e /* var e: nullable Object */;
+val* var10 /* : POSet[nullable Object] */;
+val* var12 /* : POSet[nullable Object] */;
 val* var13 /* : POSetElement[nullable Object] */;
 val* var14 /* : Collection[nullable Object] */;
 long var15 /* : Int */;
-long var16 /* : Int */;
-short int var17 /* : Bool */;
-short int var19 /* : Bool */;
+short int var16 /* : Bool */;
+short int var18 /* : Bool */;
 int cltype;
 int idtype;
 const char* var_class_name;
-short int var20 /* : Bool */;
-val* var21 /* : HashSet[Object] */;
-val* var23 /* : HashSet[Object] */;
-val* var24 /* : POSet[Object] */;
-val* var26 /* : POSet[Object] */;
-val* var27 /* : POSetElement[nullable Object] */;
-val* var28 /* : Collection[nullable Object] */;
-{
-{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[Object]> */
-var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[Object]> */
+short int var19 /* : Bool */;
+val* var20 /* : HashSet[nullable Object] */;
+val* var22 /* : HashSet[nullable Object] */;
+val* var23 /* : POSet[nullable Object] */;
+val* var25 /* : POSet[nullable Object] */;
+val* var26 /* : POSetElement[nullable Object] */;
+val* var27 /* : Collection[nullable Object] */;
+{
+{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[nullable Object]> */
+var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var2 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var2;
 RET_LABEL1:(void)0;
 }
 }
 {
-standard___standard__HashSet___standard__abstract_collection__RemovableCollection__clear(var); /* Direct call hash_collection#HashSet#clear on <var:HashSet[Object]>*/
+standard___standard__HashSet___standard__abstract_collection__RemovableCollection__clear(var); /* Direct call hash_collection#HashSet#clear on <var:HashSet[nullable Object]>*/
 }
 {
-{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[Object]> */
-var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var5 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
 }
 var3 = var5;
 RET_LABEL4:(void)0;
@@ -175,20 +273,20 @@ var6 = poset___poset__POSet___standard__abstract_collection__Collection__iterato
 var_7 = var6;
 for(;;) {
 {
-var8 = ((short int (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7) /* is_ok on <var_7:Iterator[Object]>*/;
+var8 = ((short int(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7); /* is_ok on <var_7:Iterator[nullable Object]>*/
 }
 if (var8){
 {
-var9 = ((val* (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7) /* item on <var_7:Iterator[Object]>*/;
+var9 = ((val*(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7); /* item on <var_7:Iterator[nullable Object]>*/
 }
 var_e = var9;
 {
-{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[Object]> */
-var12 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var12 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var12 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
 }
 var10 = var12;
 RET_LABEL11:(void)0;
@@ -201,64 +299,63 @@ var13 = poset___poset__POSet____91d_93d(var10, var_e);
 var14 = poset___poset__POSetElement___direct_greaters(var13);
 }
 {
-var15 = ((long (*)(val* self))(var14->class->vft[COLOR_standard__abstract_collection__Collection__length]))(var14) /* length on <var14:Collection[nullable Object](Collection[Object])>*/;
+var15 = ((long(*)(val* self))((((long)var14&3)?class_info[((long)var14&3)]:var14->class)->vft[COLOR_standard__abstract_collection__Collection__length]))(var14); /* length on <var14:Collection[nullable Object]>*/
 }
-var16 = 1;
 {
-{ /* Inline kernel#Int#> (var15,var16) on <var15:Int> */
-/* Covariant cast for argument 0 (i) <var16:Int> isa OTHER */
-/* <var16:Int> isa OTHER */
-var19 = 1; /* easy <var16:Int> isa OTHER*/
-if (unlikely(!var19)) {
+{ /* Inline kernel#Int#> (var15,1l) on <var15:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var18 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var18)) {
 var_class_name = type_standard__Int.name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 412);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 536);
+fatal_exit(1);
 }
-var20 = var15 > var16;
-var17 = var20;
-goto RET_LABEL18;
-RET_LABEL18:(void)0;
+var19 = var15 > 1l;
+var16 = var19;
+goto RET_LABEL17;
+RET_LABEL17:(void)0;
 }
 }
-if (var17){
+if (var16){
 {
-{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[Object]> */
-var23 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[Object]> */
-if (unlikely(var23 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[nullable Object]> */
+var22 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var22 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
-var21 = var23;
-RET_LABEL22:(void)0;
+var20 = var22;
+RET_LABEL21:(void)0;
 }
 }
 {
-{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[Object]> */
-var26 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[Object]> */
-if (unlikely(var26 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var25 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var25 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
 }
-var24 = var26;
-RET_LABEL25:(void)0;
+var23 = var25;
+RET_LABEL24:(void)0;
 }
 }
 {
-var27 = poset___poset__POSet____91d_93d(var24, var_e);
+var26 = poset___poset__POSet____91d_93d(var23, var_e);
 }
 {
-var28 = poset___poset__POSetElement___greaters(var27);
+var27 = poset___poset__POSetElement___greaters(var26);
 }
 {
-standard___standard__SimpleCollection___add_all(var21, var28); /* Direct call abstract_collection#SimpleCollection#add_all on <var21:HashSet[Object]>*/
+standard___standard__SimpleCollection___add_all(var20, var27); /* Direct call abstract_collection#SimpleCollection#add_all on <var20:HashSet[nullable Object]>*/
 }
 } else {
 }
 {
-((void (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7) /* next on <var_7:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7); /* next on <var_7:Iterator[nullable Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -266,60 +363,58 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_7) on <var_7:Iterator[Object]> */
-RET_LABEL29:(void)0;
-}
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_7); /* finish on <var_7:Iterator[nullable Object]>*/
 }
 RET_LABEL:;
 }
-/* method coloring#POSetConflictGraph#extract_border for (self: POSetConflictGraph[Object]) */
+/* method coloring#POSetConflictGraph#extract_border for (self: POSetConflictGraph[nullable Object]) */
 void nit___nit__POSetConflictGraph___extract_border(val* self) {
-val* var /* : HashSet[Object] */;
-val* var2 /* : HashSet[Object] */;
-val* var3 /* : HashSet[Object] */;
-val* var5 /* : HashSet[Object] */;
-val* var_ /* var : HashSet[Object] */;
+val* var /* : HashSet[nullable Object] */;
+val* var2 /* : HashSet[nullable Object] */;
+val* var3 /* : HashSet[nullable Object] */;
+val* var5 /* : HashSet[nullable Object] */;
+val* var_ /* var : HashSet[nullable Object] */;
 val* var6 /* : Iterator[nullable Object] */;
-val* var_7 /* var : Iterator[Object] */;
+val* var_7 /* var : Iterator[nullable Object] */;
 short int var8 /* : Bool */;
 val* var9 /* : nullable Object */;
-val* var_e /* var e: Object */;
+val* var_e /* var e: nullable Object */;
 short int var10 /* : Bool */;
 short int var11 /* : Bool */;
-val* var12 /* : HashSet[Object] */;
-val* var14 /* : HashSet[Object] */;
-val* var17 /* : HashSet[Object] */;
-val* var19 /* : HashSet[Object] */;
-val* var_20 /* var : HashSet[Object] */;
-val* var21 /* : Iterator[nullable Object] */;
-val* var_22 /* var : Iterator[Object] */;
-short int var23 /* : Bool */;
-val* var24 /* : nullable Object */;
-val* var_e25 /* var e: Object */;
-val* var26 /* : HashSet[Object] */;
-val* var28 /* : HashSet[Object] */;
+val* var12 /* : HashSet[nullable Object] */;
+val* var14 /* : HashSet[nullable Object] */;
+val* var16 /* : HashSet[nullable Object] */;
+val* var18 /* : HashSet[nullable Object] */;
+val* var_19 /* var : HashSet[nullable Object] */;
+val* var20 /* : Iterator[nullable Object] */;
+val* var_21 /* var : Iterator[nullable Object] */;
+short int var22 /* : Bool */;
+val* var23 /* : nullable Object */;
+val* var_e24 /* var e: nullable Object */;
+val* var25 /* : HashSet[nullable Object] */;
+val* var27 /* : HashSet[nullable Object] */;
 {
-{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[Object]> */
-var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[nullable Object]> */
+var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var2 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var2;
 RET_LABEL1:(void)0;
 }
 }
 {
-standard___standard__HashSet___standard__abstract_collection__RemovableCollection__clear(var); /* Direct call hash_collection#HashSet#clear on <var:HashSet[Object]>*/
+standard___standard__HashSet___standard__abstract_collection__RemovableCollection__clear(var); /* Direct call hash_collection#HashSet#clear on <var:HashSet[nullable Object]>*/
 }
 {
-{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[Object]> */
-var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[nullable Object]> */
+var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var5 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
 var3 = var5;
 RET_LABEL4:(void)0;
@@ -332,11 +427,11 @@ var6 = standard___standard__HashSet___standard__abstract_collection__Collection_
 var_7 = var6;
 for(;;) {
 {
-var8 = ((short int (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7) /* is_ok on <var_7:Iterator[Object]>*/;
+var8 = ((short int(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7); /* is_ok on <var_7:Iterator[nullable Object]>*/
 }
 if (var8){
 {
-var9 = ((val* (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7) /* item on <var_7:Iterator[Object]>*/;
+var9 = ((val*(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7); /* item on <var_7:Iterator[nullable Object]>*/
 }
 var_e = var9;
 {
@@ -348,23 +443,23 @@ goto BREAK_label;
 } else {
 }
 {
-{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[Object]> */
-var14 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[nullable Object]> */
+var14 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var14 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
-show_backtrace(1);
+fatal_exit(1);
 }
 var12 = var14;
 RET_LABEL13:(void)0;
 }
 }
 {
-standard___standard__HashSet___standard__abstract_collection__SimpleCollection__add(var12, var_e); /* Direct call hash_collection#HashSet#add on <var12:HashSet[Object]>*/
+standard___standard__HashSet___standard__abstract_collection__SimpleCollection__add(var12, var_e); /* Direct call hash_collection#HashSet#add on <var12:HashSet[nullable Object]>*/
 }
 BREAK_label: (void)0;
 {
-((void (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7) /* next on <var_7:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7); /* next on <var_7:Iterator[nullable Object]>*/
 }
 } else {
 goto BREAK_label15;
@@ -372,114 +467,114 @@ goto BREAK_label15;
 }
 BREAK_label15: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_7) on <var_7:Iterator[Object]> */
-RET_LABEL16:(void)0;
-}
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_7); /* finish on <var_7:Iterator[nullable Object]>*/
 }
 {
-{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[Object]> */
-var19 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[Object]> */
-if (unlikely(var19 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[nullable Object]> */
+var18 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var18 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
-show_backtrace(1);
+fatal_exit(1);
 }
-var17 = var19;
-RET_LABEL18:(void)0;
+var16 = var18;
+RET_LABEL17:(void)0;
 }
 }
-var_20 = var17;
+var_19 = var16;
 {
-var21 = standard___standard__HashSet___standard__abstract_collection__Collection__iterator(var_20);
+var20 = standard___standard__HashSet___standard__abstract_collection__Collection__iterator(var_19);
 }
-var_22 = var21;
+var_21 = var20;
 for(;;) {
 {
-var23 = ((short int (*)(val* self))(var_22->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_22) /* is_ok on <var_22:Iterator[Object]>*/;
+var22 = ((short int(*)(val* self))((((long)var_21&3)?class_info[((long)var_21&3)]:var_21->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_21); /* is_ok on <var_21:Iterator[nullable Object]>*/
 }
-if (var23){
+if (var22){
 {
-var24 = ((val* (*)(val* self))(var_22->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_22) /* item on <var_22:Iterator[Object]>*/;
+var23 = ((val*(*)(val* self))((((long)var_21&3)?class_info[((long)var_21&3)]:var_21->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_21); /* item on <var_21:Iterator[nullable Object]>*/
 }
-var_e25 = var24;
+var_e24 = var23;
 {
-{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[Object]> */
-var28 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[Object]> */
-if (unlikely(var28 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[nullable Object]> */
+var27 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var27 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
-var26 = var28;
-RET_LABEL27:(void)0;
+var25 = var27;
+RET_LABEL26:(void)0;
 }
 }
 {
-standard___standard__HashSet___standard__abstract_collection__RemovableCollection__remove(var26, var_e25); /* Direct call hash_collection#HashSet#remove on <var26:HashSet[Object]>*/
+standard___standard__HashSet___standard__abstract_collection__RemovableCollection__remove(var25, var_e24); /* Direct call hash_collection#HashSet#remove on <var25:HashSet[nullable Object]>*/
 }
 {
-((void (*)(val* self))(var_22->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_22) /* next on <var_22:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_21&3)?class_info[((long)var_21&3)]:var_21->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_21); /* next on <var_21:Iterator[nullable Object]>*/
 }
 } else {
-goto BREAK_label29;
+goto BREAK_label28;
 }
 }
-BREAK_label29: (void)0;
+BREAK_label28: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_22) on <var_22:Iterator[Object]> */
-RET_LABEL30:(void)0;
-}
+((void(*)(val* self))((((long)var_21&3)?class_info[((long)var_21&3)]:var_21->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_21); /* finish on <var_21:Iterator[nullable Object]>*/
 }
 RET_LABEL:;
 }
-/* method coloring#POSetConflictGraph#is_border for (self: POSetConflictGraph[Object], Object): Bool */
+/* method coloring#POSetConflictGraph#is_border for (self: POSetConflictGraph[nullable Object], nullable Object): Bool */
 short int nit___nit__POSetConflictGraph___is_border(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_e /* var e: Object */;
-val* var2 /* : POSet[Object] */;
-val* var4 /* : POSet[Object] */;
+val* var_e /* var e: nullable Object */;
+val* var2 /* : POSet[nullable Object] */;
+val* var4 /* : POSet[nullable Object] */;
 val* var5 /* : POSetElement[nullable Object] */;
 val* var6 /* : Collection[nullable Object] */;
-val* var_ /* var : Collection[Object] */;
+val* var_ /* var : Collection[nullable Object] */;
 val* var7 /* : Iterator[nullable Object] */;
-val* var_8 /* var : Iterator[Object] */;
+val* var_8 /* var : Iterator[nullable Object] */;
 short int var9 /* : Bool */;
 val* var10 /* : nullable Object */;
-val* var_child /* var child: Object */;
-val* var11 /* : HashSet[Object] */;
-val* var13 /* : HashSet[Object] */;
+val* var_child /* var child: nullable Object */;
+val* var11 /* : HashSet[nullable Object] */;
+val* var13 /* : HashSet[nullable Object] */;
 short int var14 /* : Bool */;
-short int var15 /* : Bool */;
-short int var17 /* : Bool */;
-/* Covariant cast for argument 0 (e) <p0:Object> isa E */
-/* <p0:Object> isa E */
+/* Covariant cast for argument 0 (e) <p0:nullable Object> isa E */
+/* <p0:nullable Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_nit__POSetConflictGraph___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var1 = is_nullable;
+} else {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
+}
 }
 if (unlikely(!var1)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 78);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 83);
+fatal_exit(1);
 }
 var_e = p0;
 {
-{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[Object]> */
-var4 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var4 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var4 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
 }
 var2 = var4;
 RET_LABEL3:(void)0;
@@ -493,25 +588,25 @@ var6 = poset___poset__POSetElement___direct_smallers(var5);
 }
 var_ = var6;
 {
-var7 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[Object]>*/;
+var7 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[nullable Object]>*/
 }
 var_8 = var7;
 for(;;) {
 {
-var9 = ((short int (*)(val* self))(var_8->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_8) /* is_ok on <var_8:Iterator[Object]>*/;
+var9 = ((short int(*)(val* self))((((long)var_8&3)?class_info[((long)var_8&3)]:var_8->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_8); /* is_ok on <var_8:Iterator[nullable Object]>*/
 }
 if (var9){
 {
-var10 = ((val* (*)(val* self))(var_8->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_8) /* item on <var_8:Iterator[Object]>*/;
+var10 = ((val*(*)(val* self))((((long)var_8&3)?class_info[((long)var_8&3)]:var_8->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_8); /* item on <var_8:Iterator[nullable Object]>*/
 }
 var_child = var10;
 {
-{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[Object]> */
-var13 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[nullable Object]> */
+var13 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var13 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
 var11 = var13;
 RET_LABEL12:(void)0;
@@ -521,13 +616,12 @@ RET_LABEL12:(void)0;
 var14 = standard___standard__HashSet___standard__abstract_collection__Collection__has(var11, var_child);
 }
 if (var14){
-var15 = 0;
-var = var15;
+var = 0;
 goto RET_LABEL;
 } else {
 }
 {
-((void (*)(val* self))(var_8->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_8) /* next on <var_8:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_8&3)?class_info[((long)var_8&3)]:var_8->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_8); /* next on <var_8:Iterator[nullable Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -535,62 +629,59 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_8) on <var_8:Iterator[Object]> */
-RET_LABEL16:(void)0;
-}
+((void(*)(val* self))((((long)var_8&3)?class_info[((long)var_8&3)]:var_8->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_8); /* finish on <var_8:Iterator[nullable Object]>*/
 }
-var17 = 1;
-var = var17;
+var = 1;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method coloring#POSetConflictGraph#extract_crown for (self: POSetConflictGraph[Object]) */
+/* method coloring#POSetConflictGraph#extract_crown for (self: POSetConflictGraph[nullable Object]) */
 void nit___nit__POSetConflictGraph___extract_crown(val* self) {
-val* var /* : HashSet[Object] */;
-val* var2 /* : HashSet[Object] */;
-val* var3 /* : POSet[Object] */;
-val* var5 /* : POSet[Object] */;
-val* var_ /* var : POSet[Object] */;
+val* var /* : HashSet[nullable Object] */;
+val* var2 /* : HashSet[nullable Object] */;
+val* var3 /* : POSet[nullable Object] */;
+val* var5 /* : POSet[nullable Object] */;
+val* var_ /* var : POSet[nullable Object] */;
 val* var6 /* : Iterator[nullable Object] */;
-val* var_7 /* var : Iterator[Object] */;
+val* var_7 /* var : Iterator[nullable Object] */;
 short int var8 /* : Bool */;
 val* var9 /* : nullable Object */;
-val* var_e /* var e: Object */;
+val* var_e /* var e: nullable Object */;
 short int var10 /* : Bool */;
-val* var11 /* : HashSet[Object] */;
-val* var13 /* : HashSet[Object] */;
+val* var11 /* : HashSet[nullable Object] */;
+val* var13 /* : HashSet[nullable Object] */;
 short int var14 /* : Bool */;
 short int var15 /* : Bool */;
 short int var_16 /* var : Bool */;
-val* var17 /* : HashSet[Object] */;
-val* var19 /* : HashSet[Object] */;
+val* var17 /* : HashSet[nullable Object] */;
+val* var19 /* : HashSet[nullable Object] */;
 short int var20 /* : Bool */;
 short int var21 /* : Bool */;
-val* var22 /* : HashSet[Object] */;
-val* var24 /* : HashSet[Object] */;
+val* var22 /* : HashSet[nullable Object] */;
+val* var24 /* : HashSet[nullable Object] */;
 {
-{ /* Inline coloring#POSetConflictGraph#crown (self) on <self:POSetConflictGraph[Object]> */
-var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _crown on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#crown (self) on <self:POSetConflictGraph[nullable Object]> */
+var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _crown on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var2 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _crown");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 34);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var2;
 RET_LABEL1:(void)0;
 }
 }
 {
-standard___standard__HashSet___standard__abstract_collection__RemovableCollection__clear(var); /* Direct call hash_collection#HashSet#clear on <var:HashSet[Object]>*/
+standard___standard__HashSet___standard__abstract_collection__RemovableCollection__clear(var); /* Direct call hash_collection#HashSet#clear on <var:HashSet[nullable Object]>*/
 }
 {
-{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[Object]> */
-var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var5 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
 }
 var3 = var5;
 RET_LABEL4:(void)0;
@@ -603,20 +694,20 @@ var6 = poset___poset__POSet___standard__abstract_collection__Collection__iterato
 var_7 = var6;
 for(;;) {
 {
-var8 = ((short int (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7) /* is_ok on <var_7:Iterator[Object]>*/;
+var8 = ((short int(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7); /* is_ok on <var_7:Iterator[nullable Object]>*/
 }
 if (var8){
 {
-var9 = ((val* (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7) /* item on <var_7:Iterator[Object]>*/;
+var9 = ((val*(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7); /* item on <var_7:Iterator[nullable Object]>*/
 }
 var_e = var9;
 {
-{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[Object]> */
-var13 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#core (self) on <self:POSetConflictGraph[nullable Object]> */
+var13 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var13 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
 var11 = var13;
 RET_LABEL12:(void)0;
@@ -629,12 +720,12 @@ var15 = !var14;
 var_16 = var15;
 if (var15){
 {
-{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[Object]> */
-var19 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[nullable Object]> */
+var19 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var19 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
-show_backtrace(1);
+fatal_exit(1);
 }
 var17 = var19;
 RET_LABEL18:(void)0;
@@ -650,24 +741,24 @@ var10 = var_16;
 }
 if (var10){
 {
-{ /* Inline coloring#POSetConflictGraph#crown (self) on <self:POSetConflictGraph[Object]> */
-var24 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _crown on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#crown (self) on <self:POSetConflictGraph[nullable Object]> */
+var24 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _crown on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var24 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _crown");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 34);
-show_backtrace(1);
+fatal_exit(1);
 }
 var22 = var24;
 RET_LABEL23:(void)0;
 }
 }
 {
-standard___standard__HashSet___standard__abstract_collection__SimpleCollection__add(var22, var_e); /* Direct call hash_collection#HashSet#add on <var22:HashSet[Object]>*/
+standard___standard__HashSet___standard__abstract_collection__SimpleCollection__add(var22, var_e); /* Direct call hash_collection#HashSet#add on <var22:HashSet[nullable Object]>*/
 }
 } else {
 }
 {
-((void (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7) /* next on <var_7:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7); /* next on <var_7:Iterator[nullable Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -675,50 +766,48 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_7) on <var_7:Iterator[Object]> */
-RET_LABEL25:(void)0;
-}
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_7); /* finish on <var_7:Iterator[nullable Object]>*/
 }
 RET_LABEL:;
 }
-/* method coloring#POSetConflictGraph#compute_conflicts for (self: POSetConflictGraph[Object]) */
+/* method coloring#POSetConflictGraph#compute_conflicts for (self: POSetConflictGraph[nullable Object]) */
 void nit___nit__POSetConflictGraph___compute_conflicts(val* self) {
-val* var /* : HashMap[Object, Set[Object]] */;
-val* var2 /* : HashMap[Object, Set[Object]] */;
-val* var3 /* : HashSet[Object] */;
-val* var5 /* : HashSet[Object] */;
-val* var_ /* var : HashSet[Object] */;
+val* var /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var2 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var3 /* : HashSet[nullable Object] */;
+val* var5 /* : HashSet[nullable Object] */;
+val* var_ /* var : HashSet[nullable Object] */;
 val* var6 /* : Iterator[nullable Object] */;
-val* var_7 /* var : Iterator[Object] */;
+val* var_7 /* var : Iterator[nullable Object] */;
 short int var8 /* : Bool */;
 val* var9 /* : nullable Object */;
-val* var_e /* var e: Object */;
-val* var10 /* : POSet[Object] */;
-val* var12 /* : POSet[Object] */;
+val* var_e /* var e: nullable Object */;
+val* var10 /* : POSet[nullable Object] */;
+val* var12 /* : POSet[nullable Object] */;
 val* var13 /* : POSetElement[nullable Object] */;
 val* var14 /* : Collection[nullable Object] */;
 {
-{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[Object]> */
-var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[nullable Object]> */
+var2 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var2 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
 var = var2;
 RET_LABEL1:(void)0;
 }
 }
 {
-standard___standard__HashMap___standard__abstract_collection__Map__clear(var); /* Direct call hash_collection#HashMap#clear on <var:HashMap[Object, Set[Object]]>*/
+standard___standard__HashMap___standard__abstract_collection__Map__clear(var); /* Direct call hash_collection#HashMap#clear on <var:HashMap[nullable Object, Set[nullable Object]]>*/
 }
 {
-{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[Object]> */
-var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#border (self) on <self:POSetConflictGraph[nullable Object]> */
+var5 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var5 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
-show_backtrace(1);
+fatal_exit(1);
 }
 var3 = var5;
 RET_LABEL4:(void)0;
@@ -731,20 +820,20 @@ var6 = standard___standard__HashSet___standard__abstract_collection__Collection_
 var_7 = var6;
 for(;;) {
 {
-var8 = ((short int (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7) /* is_ok on <var_7:Iterator[Object]>*/;
+var8 = ((short int(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7); /* is_ok on <var_7:Iterator[nullable Object]>*/
 }
 if (var8){
 {
-var9 = ((val* (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7) /* item on <var_7:Iterator[Object]>*/;
+var9 = ((val*(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7); /* item on <var_7:Iterator[nullable Object]>*/
 }
 var_e = var9;
 {
-{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[Object]> */
-var12 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[Object]> */
+{ /* Inline coloring#POSetConflictGraph#poset (self) on <self:POSetConflictGraph[nullable Object]> */
+var12 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <self:POSetConflictGraph[nullable Object]> */
 if (unlikely(var12 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
-show_backtrace(1);
+fatal_exit(1);
 }
 var10 = var12;
 RET_LABEL11:(void)0;
@@ -757,10 +846,10 @@ var13 = poset___poset__POSet____91d_93d(var10, var_e);
 var14 = poset___poset__POSetElement___greaters(var13);
 }
 {
-nit___nit__POSetConflictGraph___add_conflicts(self, var14); /* Direct call coloring#POSetConflictGraph#add_conflicts on <self:POSetConflictGraph[Object]>*/
+nit___nit__POSetConflictGraph___add_conflicts(self, var14); /* Direct call coloring#POSetConflictGraph#add_conflicts on <self:POSetConflictGraph[nullable Object]>*/
 }
 {
-((void (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7) /* next on <var_7:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7); /* next on <var_7:Iterator[nullable Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -768,264 +857,274 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_7) on <var_7:Iterator[Object]> */
-RET_LABEL15:(void)0;
-}
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_7); /* finish on <var_7:Iterator[nullable Object]>*/
 }
 RET_LABEL:;
 }
-/* method coloring#POSetConflictGraph#add_conflict for (self: POSetConflictGraph[Object], Object, Object) */
+/* method coloring#POSetConflictGraph#add_conflict for (self: POSetConflictGraph[nullable Object], nullable Object, nullable Object) */
 void nit___nit__POSetConflictGraph___add_conflict(val* self, val* p0, val* p1) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
+short int is_nullable;
 const char* var_class_name;
 short int var1 /* : Bool */;
 int cltype2;
 int idtype3;
 const struct type* type_struct4;
-const char* var_class_name5;
-val* var_e /* var e: Object */;
-val* var_o /* var o: Object */;
-val* var6 /* : HashMap[Object, Set[Object]] */;
-val* var8 /* : HashMap[Object, Set[Object]] */;
-short int var9 /* : Bool */;
+short int is_nullable5;
+const char* var_class_name6;
+val* var_e /* var e: nullable Object */;
+val* var_o /* var o: nullable Object */;
+val* var7 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var9 /* : HashMap[nullable Object, Set[nullable Object]] */;
 short int var10 /* : Bool */;
-val* var11 /* : HashMap[Object, Set[Object]] */;
-val* var13 /* : HashMap[Object, Set[Object]] */;
-val* var14 /* : HashSet[Object] */;
-val* var15 /* : HashMap[Object, Set[Object]] */;
-val* var17 /* : HashMap[Object, Set[Object]] */;
-short int var18 /* : Bool */;
+short int var11 /* : Bool */;
+val* var12 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var14 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var15 /* : HashSet[nullable Object] */;
+val* var16 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var18 /* : HashMap[nullable Object, Set[nullable Object]] */;
 short int var19 /* : Bool */;
-val* var20 /* : HashMap[Object, Set[Object]] */;
-val* var22 /* : HashMap[Object, Set[Object]] */;
-val* var23 /* : HashSet[Object] */;
-val* var24 /* : HashMap[Object, Set[Object]] */;
-val* var26 /* : HashMap[Object, Set[Object]] */;
-val* var27 /* : nullable Object */;
-val* var28 /* : HashMap[Object, Set[Object]] */;
-val* var30 /* : HashMap[Object, Set[Object]] */;
-val* var31 /* : nullable Object */;
-/* Covariant cast for argument 0 (e) <p0:Object> isa E */
-/* <p0:Object> isa E */
+short int var20 /* : Bool */;
+val* var21 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var23 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var24 /* : HashSet[nullable Object] */;
+val* var25 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var27 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var28 /* : nullable Object */;
+val* var29 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var31 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var32 /* : 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_nit__POSetConflictGraph___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+is_nullable = type_struct->is_nullable;
+if(p0 == NULL) {
+var = is_nullable;
+} else {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var = 0;
 } else {
-var = p0->type->type_table[cltype] == idtype;
+var = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
+}
 }
 if (unlikely(!var)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 100);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 105);
+fatal_exit(1);
 }
-/* Covariant cast for argument 1 (o) <p1:Object> isa E */
-/* <p1:Object> isa E */
+/* Covariant cast for argument 1 (o) <p1:nullable Object> isa E */
+/* <p1:nullable Object> isa E */
 type_struct4 = self->type->resolution_table->types[COLOR_nit__POSetConflictGraph___35dE];
 cltype2 = type_struct4->color;
 idtype3 = type_struct4->id;
-if(cltype2 >= p1->type->table_size) {
+is_nullable5 = type_struct4->is_nullable;
+if(p1 == NULL) {
+var1 = is_nullable5;
+} else {
+if(cltype2 >= (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p1->type->type_table[cltype2] == idtype3;
+var1 = (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->type_table[cltype2] == idtype3;
+}
 }
 if (unlikely(!var1)) {
-var_class_name5 = p1 == NULL ? "null" : p1->type->name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name5);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 100);
-show_backtrace(1);
+var_class_name6 = p1 == NULL ? "null" : (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name6);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 105);
+fatal_exit(1);
 }
 var_e = p0;
 var_o = p1;
 {
-{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[Object]> */
-var8 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
-if (unlikely(var8 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[nullable Object]> */
+var9 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var9 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
-var6 = var8;
-RET_LABEL7:(void)0;
+var7 = var9;
+RET_LABEL8:(void)0;
 }
 }
 {
-var9 = standard___standard__MapRead___has_key(var6, var_e);
+var10 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var7, var_e);
 }
-var10 = !var9;
-if (var10){
+var11 = !var10;
+if (var11){
 {
-{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[Object]> */
-var13 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
-if (unlikely(var13 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[nullable Object]> */
+var14 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var14 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
-var11 = var13;
-RET_LABEL12:(void)0;
+var12 = var14;
+RET_LABEL13:(void)0;
 }
 }
-var14 = NEW_standard__HashSet(self->type->resolution_table->types[COLOR_standard__HashSet__nit__POSetConflictGraph___35dE]);
+var15 = NEW_standard__HashSet(self->type->resolution_table->types[COLOR_standard__HashSet__nit__POSetConflictGraph___35dE]);
 {
-standard___standard__HashSet___standard__kernel__Object__init(var14); /* Direct call hash_collection#HashSet#init on <var14:HashSet[Object]>*/
+standard___standard__HashSet___standard__kernel__Object__init(var15); /* Direct call hash_collection#HashSet#init on <var15:HashSet[nullable Object]>*/
 }
 {
-standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var11, var_e, var14); /* Direct call hash_collection#HashMap#[]= on <var11:HashMap[Object, Set[Object]]>*/
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var12, var_e, var15); /* Direct call hash_collection#HashMap#[]= on <var12:HashMap[nullable Object, Set[nullable Object]]>*/
 }
 } else {
 }
 {
-{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[Object]> */
-var17 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
-if (unlikely(var17 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[nullable Object]> */
+var18 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var18 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
-var15 = var17;
-RET_LABEL16:(void)0;
+var16 = var18;
+RET_LABEL17:(void)0;
 }
 }
 {
-var18 = standard___standard__MapRead___has_key(var15, var_o);
+var19 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var16, var_o);
 }
-var19 = !var18;
-if (var19){
+var20 = !var19;
+if (var20){
 {
-{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[Object]> */
-var22 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
-if (unlikely(var22 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[nullable Object]> */
+var23 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var23 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
-var20 = var22;
-RET_LABEL21:(void)0;
+var21 = var23;
+RET_LABEL22:(void)0;
 }
 }
-var23 = NEW_standard__HashSet(self->type->resolution_table->types[COLOR_standard__HashSet__nit__POSetConflictGraph___35dE]);
+var24 = NEW_standard__HashSet(self->type->resolution_table->types[COLOR_standard__HashSet__nit__POSetConflictGraph___35dE]);
 {
-standard___standard__HashSet___standard__kernel__Object__init(var23); /* Direct call hash_collection#HashSet#init on <var23:HashSet[Object]>*/
+standard___standard__HashSet___standard__kernel__Object__init(var24); /* Direct call hash_collection#HashSet#init on <var24:HashSet[nullable Object]>*/
 }
 {
-standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var20, var_o, var23); /* Direct call hash_collection#HashMap#[]= on <var20:HashMap[Object, Set[Object]]>*/
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var21, var_o, var24); /* Direct call hash_collection#HashMap#[]= on <var21:HashMap[nullable Object, Set[nullable Object]]>*/
 }
 } else {
 }
 {
-{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[Object]> */
-var26 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
-if (unlikely(var26 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[nullable Object]> */
+var27 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var27 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
-var24 = var26;
-RET_LABEL25:(void)0;
+var25 = var27;
+RET_LABEL26:(void)0;
 }
 }
 {
-var27 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var24, var_e);
+var28 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var25, var_e);
 }
 {
-((void (*)(val* self, val* p0))(var27->class->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var27, var_o) /* add on <var27:nullable Object(Set[Object])>*/;
+((void(*)(val* self, val* p0))((((long)var28&3)?class_info[((long)var28&3)]:var28->class)->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var28, var_o); /* add on <var28:nullable Object(Set[nullable Object])>*/
 }
 {
-{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[Object]> */
-var30 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[Object]> */
-if (unlikely(var30 == NULL)) {
+{ /* Inline coloring#POSetConflictGraph#conflicts (self) on <self:POSetConflictGraph[nullable Object]> */
+var31 = self->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <self:POSetConflictGraph[nullable Object]> */
+if (unlikely(var31 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
-var28 = var30;
-RET_LABEL29:(void)0;
+var29 = var31;
+RET_LABEL30:(void)0;
 }
 }
 {
-var31 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var28, var_o);
+var32 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var29, var_o);
 }
 {
-((void (*)(val* self, val* p0))(var31->class->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var31, var_e) /* add on <var31:nullable Object(Set[Object])>*/;
+((void(*)(val* self, val* p0))((((long)var32&3)?class_info[((long)var32&3)]:var32->class)->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var32, var_e); /* add on <var32:nullable Object(Set[nullable Object])>*/
 }
 RET_LABEL:;
 }
-/* method coloring#POSetConflictGraph#add_conflicts for (self: POSetConflictGraph[Object], Collection[Object]) */
+/* method coloring#POSetConflictGraph#add_conflicts for (self: POSetConflictGraph[nullable Object], Collection[nullable Object]) */
 void nit___nit__POSetConflictGraph___add_conflicts(val* self, val* p0) {
 short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 const char* var_class_name;
-val* var_es /* var es: Collection[Object] */;
-val* var_ /* var : Collection[Object] */;
+val* var_es /* var es: Collection[nullable Object] */;
+val* var_ /* var : Collection[nullable Object] */;
 val* var1 /* : Iterator[nullable Object] */;
-val* var_2 /* var : Iterator[Object] */;
+val* var_2 /* var : Iterator[nullable Object] */;
 short int var3 /* : Bool */;
 val* var4 /* : nullable Object */;
-val* var_e1 /* var e1: Object */;
-val* var_5 /* var : Collection[Object] */;
+val* var_e1 /* var e1: nullable Object */;
+val* var_5 /* var : Collection[nullable Object] */;
 val* var6 /* : Iterator[nullable Object] */;
-val* var_7 /* var : Iterator[Object] */;
+val* var_7 /* var : Iterator[nullable Object] */;
 short int var8 /* : Bool */;
 val* var9 /* : nullable Object */;
-val* var_e2 /* var e2: Object */;
-/* Covariant cast for argument 0 (es) <p0:Collection[Object]> isa Collection[E] */
-/* <p0:Collection[Object]> isa Collection[E] */
+val* var_e2 /* var e2: nullable Object */;
+/* Covariant cast for argument 0 (es) <p0:Collection[nullable Object]> isa Collection[E] */
+/* <p0:Collection[nullable Object]> isa Collection[E] */
 type_struct = self->type->resolution_table->types[COLOR_standard__Collection__nit__POSetConflictGraph___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var = 0;
 } else {
-var = p0->type->type_table[cltype] == idtype;
+var = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 107);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 112);
+fatal_exit(1);
 }
 var_es = p0;
 var_ = var_es;
 {
-var1 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[Object]>*/;
+var1 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[nullable Object]>*/
 }
 var_2 = var1;
 for(;;) {
 {
-var3 = ((short int (*)(val* self))(var_2->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_2) /* is_ok on <var_2:Iterator[Object]>*/;
+var3 = ((short int(*)(val* self))((((long)var_2&3)?class_info[((long)var_2&3)]:var_2->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_2); /* is_ok on <var_2:Iterator[nullable Object]>*/
 }
 if (var3){
 {
-var4 = ((val* (*)(val* self))(var_2->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_2) /* item on <var_2:Iterator[Object]>*/;
+var4 = ((val*(*)(val* self))((((long)var_2&3)?class_info[((long)var_2&3)]:var_2->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_2); /* item on <var_2:Iterator[nullable Object]>*/
 }
 var_e1 = var4;
 var_5 = var_es;
 {
-var6 = ((val* (*)(val* self))(var_5->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_5) /* iterator on <var_5:Collection[Object]>*/;
+var6 = ((val*(*)(val* self))((((long)var_5&3)?class_info[((long)var_5&3)]:var_5->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_5); /* iterator on <var_5:Collection[nullable Object]>*/
 }
 var_7 = var6;
 for(;;) {
 {
-var8 = ((short int (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7) /* is_ok on <var_7:Iterator[Object]>*/;
+var8 = ((short int(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7); /* is_ok on <var_7:Iterator[nullable Object]>*/
 }
 if (var8){
 {
-var9 = ((val* (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7) /* item on <var_7:Iterator[Object]>*/;
+var9 = ((val*(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7); /* item on <var_7:Iterator[nullable Object]>*/
 }
 var_e2 = var9;
 {
-nit___nit__POSetConflictGraph___add_conflict(self, var_e1, var_e2); /* Direct call coloring#POSetConflictGraph#add_conflict on <self:POSetConflictGraph[Object]>*/
+nit___nit__POSetConflictGraph___add_conflict(self, var_e1, var_e2); /* Direct call coloring#POSetConflictGraph#add_conflict on <self:POSetConflictGraph[nullable Object]>*/
 }
 {
-((void (*)(val* self))(var_7->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7) /* next on <var_7:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7); /* next on <var_7:Iterator[nullable Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -1033,24 +1132,36 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_7) on <var_7:Iterator[Object]> */
-RET_LABEL10:(void)0;
-}
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_7); /* finish on <var_7:Iterator[nullable Object]>*/
 }
 {
-((void (*)(val* self))(var_2->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_2) /* next on <var_2:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_2&3)?class_info[((long)var_2&3)]:var_2->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_2); /* next on <var_2:Iterator[nullable Object]>*/
 }
 } else {
-goto BREAK_label11;
+goto BREAK_label10;
 }
 }
-BREAK_label11: (void)0;
+BREAK_label10: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_2) on <var_2:Iterator[Object]> */
-RET_LABEL12:(void)0;
+((void(*)(val* self))((((long)var_2&3)?class_info[((long)var_2&3)]:var_2->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_2); /* finish on <var_2:Iterator[nullable Object]>*/
+}
+RET_LABEL:;
 }
+/* method coloring#POSet#to_conflict_graph for (self: POSet[nullable Object]): POSetConflictGraph[nullable Object] */
+val* nit__coloring___poset__POSet___to_conflict_graph(val* self) {
+val* var /* : POSetConflictGraph[nullable Object] */;
+val* var1 /* : POSetConflictGraph[nullable Object] */;
+var1 = NEW_nit__POSetConflictGraph(self->type->resolution_table->types[COLOR_nit__POSetConflictGraph__poset__POSet___35dE]);
+{
+((void(*)(val* self, val* p0))(var1->class->vft[COLOR_nit__coloring__POSetConflictGraph__poset_61d]))(var1, self); /* poset= on <var1:POSetConflictGraph[nullable Object]>*/
+}
+{
+((void(*)(val* self))(var1->class->vft[COLOR_standard__kernel__Object__init]))(var1); /* init on <var1:POSetConflictGraph[nullable Object]>*/
 }
+var = var1;
+goto RET_LABEL;
 RET_LABEL:;
+return var;
 }
 /* method coloring#POSetColorer#is_colored for (self: POSetColorer[Object]): Bool */
 short int nit___nit__POSetColorer___is_colored(val* self) {
@@ -1082,16 +1193,16 @@ RET_LABEL2:(void)0;
 }
 if (unlikely(!var1)) {
 PRINT_ERROR("Runtime error: %s", "Assert failed");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 167);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 176);
+fatal_exit(1);
 }
 {
 { /* Inline coloring#POSetColorer#ids_cache (self) on <self:POSetColorer[Object]> */
 var6 = self->attrs[COLOR_nit__coloring__POSetColorer___ids_cache].val; /* _ids_cache on <self:POSetColorer[Object]> */
 if (unlikely(var6 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _ids_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 170);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 179);
+fatal_exit(1);
 }
 var4 = var6;
 RET_LABEL5:(void)0;
@@ -1109,8 +1220,8 @@ val* var1 /* : HashMap[Object, Int] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetColorer___ids_cache].val; /* _ids_cache on <self:POSetColorer[Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _ids_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 170);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 179);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -1132,16 +1243,16 @@ RET_LABEL2:(void)0;
 }
 if (unlikely(!var1)) {
 PRINT_ERROR("Runtime error: %s", "Assert failed");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 175);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 184);
+fatal_exit(1);
 }
 {
 { /* Inline coloring#POSetColorer#colors_cache (self) on <self:POSetColorer[Object]> */
 var6 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
 if (unlikely(var6 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
 var4 = var6;
 RET_LABEL5:(void)0;
@@ -1159,8 +1270,8 @@ val* var1 /* : HashMap[Object, Int] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -1173,8 +1284,8 @@ val* var1 /* : POSet[Object] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val; /* _poset_cache on <self:POSetColorer[Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -1200,8 +1311,8 @@ 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`", "POSet[E]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val = p0; /* _poset_cache on <self:POSetColorer[Object]> */
 RET_LABEL:;
@@ -1222,16 +1333,16 @@ RET_LABEL2:(void)0;
 }
 if (unlikely(!var1)) {
 PRINT_ERROR("Runtime error: %s", "Assert failed");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 189);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 198);
+fatal_exit(1);
 }
 {
 { /* Inline coloring#POSetColorer#conflicts_cache (self) on <self:POSetColorer[Object]> */
 var6 = self->attrs[COLOR_nit__coloring__POSetColorer___conflicts_cache].val; /* _conflicts_cache on <self:POSetColorer[Object]> */
 if (unlikely(var6 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 192);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 201);
+fatal_exit(1);
 }
 var4 = var6;
 RET_LABEL5:(void)0;
@@ -1249,8 +1360,8 @@ val* var1 /* : Map[Object, Set[Object]] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetColorer___conflicts_cache].val; /* _conflicts_cache on <self:POSetColorer[Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 192);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 201);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -1268,16 +1379,16 @@ const char* var_class_name;
 type_struct = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetColorer___35dE__standard__Set__nit__POSetColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var = 0;
 } else {
-var = p0->type->type_table[cltype] == idtype;
+var = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[E, Set[E]]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 192);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 201);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetColorer___conflicts_cache].val = p0; /* _conflicts_cache on <self:POSetColorer[Object]> */
 RET_LABEL:;
@@ -1289,8 +1400,8 @@ val* var1 /* : POSetConflictGraph[Object] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetColorer___graph].val; /* _graph on <self:POSetColorer[Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -1316,8 +1427,8 @@ 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`", "POSetConflictGraph[E]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetColorer___graph].val = p0; /* _graph on <self:POSetColorer[Object]> */
 RET_LABEL:;
@@ -1343,14 +1454,13 @@ const struct type* type_struct12;
 const char* var_class_name13;
 val* var14 /* : POSetConflictGraph[Object] */;
 val* var16 /* : POSetConflictGraph[Object] */;
-val* var17 /* : HashMap[Object, Set[Object]] */;
-val* var19 /* : HashMap[Object, Set[Object]] */;
+val* var17 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var19 /* : HashMap[nullable Object, Set[nullable Object]] */;
 short int var21 /* : Bool */;
 int cltype22;
 int idtype23;
 const struct type* type_struct24;
 const char* var_class_name25;
-short int var26 /* : Bool */;
 /* Covariant cast for argument 0 (poset) <p0:POSet[Object]> isa POSet[E] */
 /* <p0:POSet[Object]> isa POSet[E] */
 type_struct = self->type->resolution_table->types[COLOR_poset__POSet__nit__POSetColorer___35dE];
@@ -1364,8 +1474,8 @@ 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`", "POSet[E]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 196);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 205);
+fatal_exit(1);
 }
 var_poset = p0;
 {
@@ -1383,8 +1493,8 @@ var2 = var_poset->type->type_table[cltype3] == idtype4;
 if (unlikely(!var2)) {
 var_class_name6 = var_poset == NULL ? "null" : var_poset->type->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "POSet[E]", var_class_name6);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val = var_poset; /* _poset_cache on <self:POSetColorer[Object]> */
 RET_LABEL1:(void)0;
@@ -1392,10 +1502,10 @@ RET_LABEL1:(void)0;
 }
 var7 = NEW_nit__POSetConflictGraph(self->type->resolution_table->types[COLOR_nit__POSetConflictGraph__nit__POSetColorer___35dE]);
 {
-((void (*)(val* self, val* p0))(var7->class->vft[COLOR_nit__coloring__POSetConflictGraph__poset_61d]))(var7, var_poset) /* poset= on <var7:POSetConflictGraph[Object]>*/;
+((void(*)(val* self, val* p0))(var7->class->vft[COLOR_nit__coloring__POSetConflictGraph__poset_61d]))(var7, var_poset); /* poset= on <var7:POSetConflictGraph[Object]>*/
 }
 {
-((void (*)(val* self))(var7->class->vft[COLOR_standard__kernel__Object__init]))(var7) /* init on <var7:POSetConflictGraph[Object]>*/;
+((void(*)(val* self))(var7->class->vft[COLOR_standard__kernel__Object__init]))(var7); /* init on <var7:POSetConflictGraph[Object]>*/
 }
 {
 { /* Inline coloring#POSetColorer#graph= (self,var7) on <self:POSetColorer[Object]> */
@@ -1412,8 +1522,8 @@ var9 = var7->type->type_table[cltype10] == idtype11;
 if (unlikely(!var9)) {
 var_class_name13 = var7 == NULL ? "null" : var7->type->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "POSetConflictGraph[E]", var_class_name13);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetColorer___graph].val = var7; /* _graph on <self:POSetColorer[Object]> */
 RET_LABEL8:(void)0;
@@ -1430,8 +1540,8 @@ nit___nit__POSetColorer___compute_colors(self); /* Direct call coloring#POSetCol
 var16 = self->attrs[COLOR_nit__coloring__POSetColorer___graph].val; /* _graph on <self:POSetColorer[Object]> */
 if (unlikely(var16 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 var14 = var16;
 RET_LABEL15:(void)0;
@@ -1443,7 +1553,7 @@ var19 = var14->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /
 if (unlikely(var19 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
 var17 = var19;
 RET_LABEL18:(void)0;
@@ -1451,8 +1561,8 @@ RET_LABEL18:(void)0;
 }
 {
 { /* Inline coloring#POSetColorer#conflicts_cache= (self,var17) on <self:POSetColorer[Object]> */
-/* Covariant cast for argument 0 (conflicts_cache) <var17:HashMap[Object, Set[Object]]> isa Map[E, Set[E]] */
-/* <var17:HashMap[Object, Set[Object]]> isa Map[E, Set[E]] */
+/* Covariant cast for argument 0 (conflicts_cache) <var17:HashMap[nullable Object, Set[nullable Object]](HashMap[Object, Set[Object]])> isa Map[E, Set[E]] */
+/* <var17:HashMap[nullable Object, Set[nullable Object]](HashMap[Object, Set[Object]])> isa Map[E, Set[E]] */
 type_struct24 = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetColorer___35dE__standard__Set__nit__POSetColorer___35dE];
 cltype22 = type_struct24->color;
 idtype23 = type_struct24->id;
@@ -1464,18 +1574,17 @@ var21 = var17->type->type_table[cltype22] == idtype23;
 if (unlikely(!var21)) {
 var_class_name25 = var17 == NULL ? "null" : var17->type->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[E, Set[E]]", var_class_name25);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 192);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 201);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetColorer___conflicts_cache].val = var17; /* _conflicts_cache on <self:POSetColorer[Object]> */
 RET_LABEL20:(void)0;
 }
 }
-var26 = 1;
 {
-{ /* Inline coloring#POSetColorer#is_colored= (self,var26) on <self:POSetColorer[Object]> */
-self->attrs[COLOR_nit__coloring__POSetColorer___is_colored].s = var26; /* _is_colored on <self:POSetColorer[Object]> */
-RET_LABEL27:(void)0;
+{ /* Inline coloring#POSetColorer#is_colored= (self,1) on <self:POSetColorer[Object]> */
+self->attrs[COLOR_nit__coloring__POSetColorer___is_colored].s = 1; /* _is_colored on <self:POSetColorer[Object]> */
+RET_LABEL26:(void)0;
 }
 }
 RET_LABEL:;
@@ -1509,8 +1618,8 @@ val* var23 /* : nullable Object */;
 var2 = self->attrs[COLOR_nit__coloring__POSetColorer___ids_cache].val; /* _ids_cache on <self:POSetColorer[Object]> */
 if (unlikely(var2 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _ids_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 170);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 179);
+fatal_exit(1);
 }
 var = var2;
 RET_LABEL1:(void)0;
@@ -1525,8 +1634,8 @@ var3 = NEW_standard__HashSet(self->type->resolution_table->types[COLOR_standard_
 var6 = self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val; /* _poset_cache on <self:POSetColorer[Object]> */
 if (unlikely(var6 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
 var4 = var6;
 RET_LABEL5:(void)0;
@@ -1544,8 +1653,8 @@ var_elements = var3;
 var10 = self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val; /* _poset_cache on <self:POSetColorer[Object]> */
 if (unlikely(var10 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
 var8 = var10;
 RET_LABEL9:(void)0;
@@ -1573,8 +1682,8 @@ var_e = var15;
 var18 = self->attrs[COLOR_nit__coloring__POSetColorer___ids_cache].val; /* _ids_cache on <self:POSetColorer[Object]> */
 if (unlikely(var18 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _ids_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 170);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 179);
+fatal_exit(1);
 }
 var16 = var18;
 RET_LABEL17:(void)0;
@@ -1585,8 +1694,8 @@ RET_LABEL17:(void)0;
 var21 = self->attrs[COLOR_nit__coloring__POSetColorer___ids_cache].val; /* _ids_cache on <self:POSetColorer[Object]> */
 if (unlikely(var21 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _ids_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 170);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 179);
+fatal_exit(1);
 }
 var19 = var21;
 RET_LABEL20:(void)0;
@@ -1596,7 +1705,7 @@ RET_LABEL20:(void)0;
 var22 = standard___standard__HashMap___standard__abstract_collection__MapRead__length(var19);
 }
 {
-var23 = BOX_standard__Int(var22); /* autobox from Int to nullable Object */
+var23 = (val*)(var22<<2|1);
 standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var16, var_e, var23); /* Direct call hash_collection#HashMap#[]= on <var16:HashMap[Object, Int]>*/
 }
 {
@@ -1608,9 +1717,7 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_13) on <var_13:ArrayIterator[Object]> */
-RET_LABEL24:(void)0;
-}
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__finish(var_13); /* Direct call array#ArrayIterator#finish on <var_13:ArrayIterator[Object]>*/
 }
 RET_LABEL:;
 }
@@ -1620,19 +1727,19 @@ val* var /* : HashMap[Object, Int] */;
 val* var2 /* : HashMap[Object, Int] */;
 val* var3 /* : POSetConflictGraph[Object] */;
 val* var5 /* : POSetConflictGraph[Object] */;
-val* var6 /* : HashSet[Object] */;
-val* var8 /* : HashSet[Object] */;
+val* var6 /* : HashSet[nullable Object] */;
+val* var8 /* : HashSet[nullable Object] */;
 val* var9 /* : POSetConflictGraph[Object] */;
 val* var11 /* : POSetConflictGraph[Object] */;
-val* var12 /* : HashSet[Object] */;
-val* var14 /* : HashSet[Object] */;
+val* var12 /* : HashSet[nullable Object] */;
+val* var14 /* : HashSet[nullable Object] */;
 {
 { /* Inline coloring#POSetColorer#colors_cache (self) on <self:POSetColorer[Object]> */
 var2 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
 if (unlikely(var2 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
 var = var2;
 RET_LABEL1:(void)0;
@@ -1649,8 +1756,8 @@ nit___nit__POSetColorer___colorize_core(self); /* Direct call coloring#POSetColo
 var5 = self->attrs[COLOR_nit__coloring__POSetColorer___graph].val; /* _graph on <self:POSetColorer[Object]> */
 if (unlikely(var5 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 var3 = var5;
 RET_LABEL4:(void)0;
@@ -1662,7 +1769,7 @@ var8 = var3->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _bo
 if (unlikely(var8 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
-show_backtrace(1);
+fatal_exit(1);
 }
 var6 = var8;
 RET_LABEL7:(void)0;
@@ -1676,8 +1783,8 @@ nit___nit__POSetColorer___colorize_set(self, var6); /* Direct call coloring#POSe
 var11 = self->attrs[COLOR_nit__coloring__POSetColorer___graph].val; /* _graph on <self:POSetColorer[Object]> */
 if (unlikely(var11 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 var9 = var11;
 RET_LABEL10:(void)0;
@@ -1689,7 +1796,7 @@ var14 = var9->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _cr
 if (unlikely(var14 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _crown");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 34);
-show_backtrace(1);
+fatal_exit(1);
 }
 var12 = var14;
 RET_LABEL13:(void)0;
@@ -1706,8 +1813,8 @@ val* var /* : POSet[Object] */;
 val* var2 /* : POSet[Object] */;
 val* var3 /* : POSetConflictGraph[Object] */;
 val* var5 /* : POSetConflictGraph[Object] */;
-val* var6 /* : HashSet[Object] */;
-val* var8 /* : HashSet[Object] */;
+val* var6 /* : HashSet[nullable Object] */;
+val* var8 /* : HashSet[nullable Object] */;
 val* var9 /* : Array[nullable Object] */;
 val* var_ /* var : Array[Object] */;
 val* var10 /* : ArrayIterator[nullable Object] */;
@@ -1719,29 +1826,28 @@ long var14 /* : Int */;
 long var_color /* var color: Int */;
 val* var15 /* : POSetConflictGraph[Object] */;
 val* var17 /* : POSetConflictGraph[Object] */;
-val* var18 /* : HashMap[Object, Set[Object]] */;
-val* var20 /* : HashMap[Object, Set[Object]] */;
+val* var18 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var20 /* : HashMap[nullable Object, Set[nullable Object]] */;
 val* var21 /* : nullable Object */;
 val* var_conflicts /* var conflicts: Set[Object] */;
 short int var22 /* : Bool */;
 short int var23 /* : Bool */;
 long var24 /* : Int */;
-long var25 /* : Int */;
-short int var27 /* : Bool */;
+short int var26 /* : Bool */;
 int cltype;
 int idtype;
 const char* var_class_name;
-long var28 /* : Int */;
-val* var29 /* : HashMap[Object, Int] */;
-val* var31 /* : HashMap[Object, Int] */;
-val* var32 /* : nullable Object */;
+long var27 /* : Int */;
+val* var28 /* : HashMap[Object, Int] */;
+val* var30 /* : HashMap[Object, Int] */;
+val* var31 /* : nullable Object */;
 {
 { /* Inline coloring#POSetColorer#poset_cache (self) on <self:POSetColorer[Object]> */
 var2 = self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val; /* _poset_cache on <self:POSetColorer[Object]> */
 if (unlikely(var2 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
 var = var2;
 RET_LABEL1:(void)0;
@@ -1752,8 +1858,8 @@ RET_LABEL1:(void)0;
 var5 = self->attrs[COLOR_nit__coloring__POSetColorer___graph].val; /* _graph on <self:POSetColorer[Object]> */
 if (unlikely(var5 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 var3 = var5;
 RET_LABEL4:(void)0;
@@ -1765,7 +1871,7 @@ var8 = var3->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core
 if (unlikely(var8 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
-show_backtrace(1);
+fatal_exit(1);
 }
 var6 = var8;
 RET_LABEL7:(void)0;
@@ -1797,8 +1903,8 @@ var_color = var14;
 var17 = self->attrs[COLOR_nit__coloring__POSetColorer___graph].val; /* _graph on <self:POSetColorer[Object]> */
 if (unlikely(var17 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 203);
+fatal_exit(1);
 }
 var15 = var17;
 RET_LABEL16:(void)0;
@@ -1810,7 +1916,7 @@ var20 = var15->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /
 if (unlikely(var20 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
 PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
-show_backtrace(1);
+fatal_exit(1);
 }
 var18 = var20;
 RET_LABEL19:(void)0;
@@ -1826,25 +1932,24 @@ var22 = nit___nit__POSetColorer___is_color_free(self, var_color, var_conflicts);
 }
 var23 = !var22;
 if (var23){
-var24 = 1;
 {
-{ /* Inline kernel#Int#+ (var_color,var24) on <var_color: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)) {
+{ /* Inline kernel#Int#+ (var_color,1l) on <var_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var26 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var26)) {
 var_class_name = type_standard__Int.name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 413);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
 }
-var28 = var_color + var24;
-var25 = var28;
-goto RET_LABEL26;
-RET_LABEL26:(void)0;
+var27 = var_color + 1l;
+var24 = var27;
+goto RET_LABEL25;
+RET_LABEL25:(void)0;
 }
 }
-var_color = var25;
+var_color = var24;
 } else {
 goto BREAK_label;
 }
@@ -1852,32 +1957,30 @@ goto BREAK_label;
 BREAK_label: (void)0;
 {
 { /* Inline coloring#POSetColorer#colors_cache (self) on <self:POSetColorer[Object]> */
-var31 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
-if (unlikely(var31 == NULL)) {
+var30 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
+if (unlikely(var30 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
-var29 = var31;
-RET_LABEL30:(void)0;
+var28 = var30;
+RET_LABEL29:(void)0;
 }
 }
 {
-var32 = BOX_standard__Int(var_color); /* autobox from Int to nullable Object */
-standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var29, var_e, var32); /* Direct call hash_collection#HashMap#[]= on <var29:HashMap[Object, Int]>*/
+var31 = (val*)(var_color<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var28, var_e, var31); /* Direct call hash_collection#HashMap#[]= on <var28:HashMap[Object, Int]>*/
 }
 {
 standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__next(var_11); /* Direct call array#ArrayIterator#next on <var_11:ArrayIterator[Object]>*/
 }
 } else {
-goto BREAK_label33;
+goto BREAK_label32;
 }
 }
-BREAK_label33: (void)0;
+BREAK_label32: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_11) on <var_11:ArrayIterator[Object]> */
-RET_LABEL34:(void)0;
-}
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__finish(var_11); /* Direct call array#ArrayIterator#finish on <var_11:ArrayIterator[Object]>*/
 }
 RET_LABEL:;
 }
@@ -1907,16 +2010,16 @@ val* var13 /* : nullable Object */;
 type_struct = self->type->resolution_table->types[COLOR_standard__Set__nit__POSetColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var = 0;
 } else {
-var = p0->type->type_table[cltype] == idtype;
+var = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Set[E]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 236);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 245);
+fatal_exit(1);
 }
 var_set = p0;
 {
@@ -1924,8 +2027,8 @@ var_set = p0;
 var3 = self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val; /* _poset_cache on <self:POSetColorer[Object]> */
 if (unlikely(var3 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
 var1 = var3;
 RET_LABEL2:(void)0;
@@ -1953,8 +2056,8 @@ var_e = var8;
 var11 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
 if (unlikely(var11 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
 var9 = var11;
 RET_LABEL10:(void)0;
@@ -1964,7 +2067,7 @@ RET_LABEL10:(void)0;
 var12 = nit___nit__POSetColorer___min_color(self, var_e);
 }
 {
-var13 = BOX_standard__Int(var12); /* autobox from Int to nullable Object */
+var13 = (val*)(var12<<2|1);
 standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var9, var_e, var13); /* Direct call hash_collection#HashMap#[]= on <var9:HashMap[Object, Int]>*/
 }
 {
@@ -1976,9 +2079,7 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_6) on <var_6:ArrayIterator[Object]> */
-RET_LABEL14:(void)0;
-}
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__finish(var_6); /* Direct call array#ArrayIterator#finish on <var_6:ArrayIterator[Object]>*/
 }
 RET_LABEL:;
 }
@@ -1992,191 +2093,185 @@ const struct type* type_struct;
 const char* var_class_name;
 val* var_e /* var e: Object */;
 long var2 /* : Int */;
-long var3 /* : Int */;
-long var5 /* : Int */;
+long var4 /* : Int */;
 long var_max_color /* var max_color: Int */;
-val* var6 /* : POSet[Object] */;
-val* var8 /* : POSet[Object] */;
-val* var9 /* : POSetElement[nullable Object] */;
-val* var10 /* : Collection[nullable Object] */;
+val* var5 /* : POSet[Object] */;
+val* var7 /* : POSet[Object] */;
+val* var8 /* : POSetElement[nullable Object] */;
+val* var9 /* : Collection[nullable Object] */;
 val* var_ /* var : Collection[Object] */;
-val* var11 /* : Iterator[nullable Object] */;
-val* var_12 /* var : Iterator[Object] */;
-short int var13 /* : Bool */;
-val* var14 /* : nullable Object */;
+val* var10 /* : Iterator[nullable Object] */;
+val* var_11 /* var : Iterator[Object] */;
+short int var12 /* : Bool */;
+val* var13 /* : nullable Object */;
 val* var_p /* var p: Object */;
-val* var15 /* : HashMap[Object, Int] */;
-val* var17 /* : HashMap[Object, Int] */;
+val* var14 /* : HashMap[Object, Int] */;
+val* var16 /* : HashMap[Object, Int] */;
+short int var17 /* : Bool */;
 short int var18 /* : Bool */;
-short int var19 /* : Bool */;
-val* var20 /* : HashMap[Object, Int] */;
-val* var22 /* : HashMap[Object, Int] */;
-val* var23 /* : nullable Object */;
-long var24 /* : Int */;
+val* var19 /* : HashMap[Object, Int] */;
+val* var21 /* : HashMap[Object, Int] */;
+val* var22 /* : nullable Object */;
+long var23 /* : Int */;
 long var_color /* var color: Int */;
-short int var25 /* : Bool */;
-short int var27 /* : Bool */;
-int cltype28;
-int idtype29;
-const char* var_class_name30;
-short int var31 /* : Bool */;
-long var34 /* : Int */;
-long var35 /* : Int */;
-short int var37 /* : Bool */;
-int cltype38;
-int idtype39;
-const char* var_class_name40;
-long var41 /* : Int */;
+short int var24 /* : Bool */;
+short int var26 /* : Bool */;
+int cltype27;
+int idtype28;
+const char* var_class_name29;
+short int var30 /* : Bool */;
+long var32 /* : Int */;
+short int var34 /* : Bool */;
+int cltype35;
+int idtype36;
+const char* var_class_name37;
+long var38 /* : Int */;
 /* Covariant cast for argument 0 (e) <p0:Object> isa E */
 /* <p0:Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_nit__POSetColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var1)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 241);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 250);
+fatal_exit(1);
 }
 var_e = p0;
-var2 = 1;
 {
-{ /* Inline kernel#Int#unary - (var2) on <var2:Int> */
-var5 = -var2;
-var3 = var5;
-goto RET_LABEL4;
-RET_LABEL4:(void)0;
+{ /* Inline kernel#Int#unary - (1l) on <1l:Int> */
+var4 = -1l;
+var2 = var4;
+goto RET_LABEL3;
+RET_LABEL3:(void)0;
 }
 }
-var_max_color = var3;
+var_max_color = var2;
 {
 { /* Inline coloring#POSetColorer#poset_cache (self) on <self:POSetColorer[Object]> */
-var8 = self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val; /* _poset_cache on <self:POSetColorer[Object]> */
-if (unlikely(var8 == NULL)) {
+var7 = self->attrs[COLOR_nit__coloring__POSetColorer___poset_cache].val; /* _poset_cache on <self:POSetColorer[Object]> */
+if (unlikely(var7 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 185);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 194);
+fatal_exit(1);
 }
-var6 = var8;
-RET_LABEL7:(void)0;
+var5 = var7;
+RET_LABEL6:(void)0;
 }
 }
 {
-var9 = poset___poset__POSet____91d_93d(var6, var_e);
+var8 = poset___poset__POSet____91d_93d(var5, var_e);
 }
 {
-var10 = poset___poset__POSetElement___direct_greaters(var9);
+var9 = poset___poset__POSetElement___direct_greaters(var8);
 }
-var_ = var10;
+var_ = var9;
 {
-var11 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[Object]>*/;
+var10 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[Object]>*/
 }
-var_12 = var11;
+var_11 = var10;
 for(;;) {
 {
-var13 = ((short int (*)(val* self))(var_12->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_12) /* is_ok on <var_12:Iterator[Object]>*/;
+var12 = ((short int(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_11); /* is_ok on <var_11:Iterator[Object]>*/
 }
-if (var13){
+if (var12){
 {
-var14 = ((val* (*)(val* self))(var_12->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_12) /* item on <var_12:Iterator[Object]>*/;
+var13 = ((val*(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_11); /* item on <var_11:Iterator[Object]>*/
 }
-var_p = var14;
+var_p = var13;
 {
 { /* Inline coloring#POSetColorer#colors_cache (self) on <self:POSetColorer[Object]> */
-var17 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
-if (unlikely(var17 == NULL)) {
+var16 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
+if (unlikely(var16 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
-var15 = var17;
-RET_LABEL16:(void)0;
+var14 = var16;
+RET_LABEL15:(void)0;
 }
 }
 {
-var18 = standard___standard__MapRead___has_key(var15, var_p);
+var17 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var14, var_p);
 }
-var19 = !var18;
-if (var19){
+var18 = !var17;
+if (var18){
 goto BREAK_label;
 } else {
 }
 {
 { /* Inline coloring#POSetColorer#colors_cache (self) on <self:POSetColorer[Object]> */
-var22 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
-if (unlikely(var22 == NULL)) {
+var21 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
+if (unlikely(var21 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
-var20 = var22;
-RET_LABEL21:(void)0;
+var19 = var21;
+RET_LABEL20:(void)0;
 }
 }
 {
-var23 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var20, var_p);
+var22 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var19, var_p);
 }
-var24 = ((struct instance_standard__Int*)var23)->value; /* autounbox from nullable Object to Int */;
-var_color = var24;
+var23 = (long)(var22)>>2;
+var_color = var23;
 {
 { /* Inline kernel#Int#> (var_color,var_max_color) on <var_color:Int> */
 /* Covariant cast for argument 0 (i) <var_max_color:Int> isa OTHER */
 /* <var_max_color:Int> isa OTHER */
-var27 = 1; /* easy <var_max_color:Int> isa OTHER*/
-if (unlikely(!var27)) {
-var_class_name30 = type_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name30);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 412);
-show_backtrace(1);
-}
-var31 = var_color > var_max_color;
-var25 = var31;
-goto RET_LABEL26;
-RET_LABEL26:(void)0;
+var26 = 1; /* easy <var_max_color:Int> isa OTHER*/
+if (unlikely(!var26)) {
+var_class_name29 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name29);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 536);
+fatal_exit(1);
+}
+var30 = var_color > var_max_color;
+var24 = var30;
+goto RET_LABEL25;
+RET_LABEL25:(void)0;
 }
 }
-if (var25){
+if (var24){
 var_max_color = var_color;
 } else {
 }
 BREAK_label: (void)0;
 {
-((void (*)(val* self))(var_12->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_12) /* next on <var_12:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_11); /* next on <var_11:Iterator[Object]>*/
 }
 } else {
-goto BREAK_label32;
+goto BREAK_label31;
 }
 }
-BREAK_label32: (void)0;
+BREAK_label31: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_12) on <var_12:Iterator[Object]> */
-RET_LABEL33:(void)0;
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_11); /* finish on <var_11:Iterator[Object]>*/
 }
-}
-var34 = 1;
 {
-{ /* Inline kernel#Int#+ (var_max_color,var34) on <var_max_color:Int> */
-/* Covariant cast for argument 0 (i) <var34:Int> isa OTHER */
-/* <var34:Int> isa OTHER */
-var37 = 1; /* easy <var34:Int> isa OTHER*/
-if (unlikely(!var37)) {
-var_class_name40 = type_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name40);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 413);
-show_backtrace(1);
+{ /* Inline kernel#Int#+ (var_max_color,1l) on <var_max_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var34 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var34)) {
+var_class_name37 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name37);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
 }
-var41 = var_max_color + var34;
-var35 = var41;
-goto RET_LABEL36;
-RET_LABEL36:(void)0;
+var38 = var_max_color + 1l;
+var32 = var38;
+goto RET_LABEL33;
+RET_LABEL33:(void)0;
 }
 }
-var = var35;
+var = var32;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2208,38 +2303,36 @@ val* var15 /* : nullable Object */;
 short int var16 /* : Bool */;
 short int var18 /* : Bool */;
 long var19 /* : Int */;
-short int var20 /* : Bool */;
-short int var22 /* : Bool */;
 /* Covariant cast for argument 1 (set) <p1:Collection[Object]> isa Collection[E] */
 /* <p1:Collection[Object]> isa Collection[E] */
 type_struct = self->type->resolution_table->types[COLOR_standard__Collection__nit__POSetColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p1->type->table_size) {
+if(cltype >= (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p1->type->type_table[cltype] == idtype;
+var1 = (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var1)) {
-var_class_name = p1 == NULL ? "null" : p1->type->name;
+var_class_name = p1 == NULL ? "null" : (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[E]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 252);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 261);
+fatal_exit(1);
 }
 var_color = p0;
 var_set = p1;
 var_ = var_set;
 {
-var2 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[Object]>*/;
+var2 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[Object]>*/
 }
 var_3 = var2;
 for(;;) {
 {
-var4 = ((short int (*)(val* self))(var_3->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_3) /* is_ok on <var_3:Iterator[Object]>*/;
+var4 = ((short int(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_3); /* is_ok on <var_3:Iterator[Object]>*/
 }
 if (var4){
 {
-var5 = ((val* (*)(val* self))(var_3->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_3) /* item on <var_3:Iterator[Object]>*/;
+var5 = ((val*(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_3); /* item on <var_3:Iterator[Object]>*/
 }
 var_e = var5;
 {
@@ -2247,15 +2340,15 @@ var_e = var5;
 var9 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
 if (unlikely(var9 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
 var7 = var9;
 RET_LABEL8:(void)0;
 }
 }
 {
-var10 = standard___standard__MapRead___has_key(var7, var_e);
+var10 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var7, var_e);
 }
 var_11 = var10;
 if (var10){
@@ -2264,8 +2357,8 @@ if (var10){
 var14 = self->attrs[COLOR_nit__coloring__POSetColorer___colors_cache].val; /* _colors_cache on <self:POSetColorer[Object]> */
 if (unlikely(var14 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 178);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 187);
+fatal_exit(1);
 }
 var12 = var14;
 RET_LABEL13:(void)0;
@@ -2276,11 +2369,8 @@ var15 = standard___standard__HashMap___standard__abstract_collection__MapRead___
 }
 {
 { /* Inline kernel#Int#== (var15,var_color) on <var15:nullable Object(Int)> */
-var18 = (var15 != NULL) && (var15->class == &class_standard__Int);
-if (var18) {
-var19 = ((struct instance_standard__Int*)var15)->value; /* autounbox from nullable Object to Int */;
-var18 = (var19 == var_color);
-}
+var19 = (long)(var15)>>2;
+var18 = (var15 != NULL) && (var19 == var_color);
 var16 = var18;
 goto RET_LABEL17;
 RET_LABEL17:(void)0;
@@ -2291,13 +2381,12 @@ var6 = var16;
 var6 = var_11;
 }
 if (var6){
-var20 = 0;
-var = var20;
+var = 0;
 goto RET_LABEL;
 } else {
 }
 {
-((void (*)(val* self))(var_3->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_3) /* next on <var_3:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_3); /* next on <var_3:Iterator[Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -2305,248 +2394,1927 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_3) on <var_3:Iterator[Object]> */
-RET_LABEL21:(void)0;
-}
+((void(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_3); /* finish on <var_3:Iterator[Object]>*/
 }
-var22 = 1;
-var = var22;
+var = 1;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
 }
-/* method coloring#BucketsColorer#colors for (self: BucketsColorer[Object, Object]): HashMap[Object, Int] */
-val* nit___nit__BucketsColorer___colors(val* self) {
-val* var /* : HashMap[Object, Int] */;
-val* var1 /* : HashMap[Object, Int] */;
-var1 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
+/* method coloring#POSetGroupColorer#graph for (self: POSetGroupColorer[Object, Object]): POSetConflictGraph[Object] */
+val* nit___nit__POSetGroupColorer___graph(val* self) {
+val* var /* : POSetConflictGraph[Object] */;
+val* var1 /* : POSetConflictGraph[Object] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
 if (unlikely(var1 == NULL)) {
-PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 284);
-show_backtrace(1);
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method coloring#BucketsColorer#conflicts for (self: BucketsColorer[Object, Object]): HashMap[Object, Set[Object]] */
-val* nit___nit__BucketsColorer___conflicts(val* self) {
-val* var /* : HashMap[Object, Set[Object]] */;
-val* var1 /* : HashMap[Object, Set[Object]] */;
-var1 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
+/* method coloring#POSetGroupColorer#graph= for (self: POSetGroupColorer[Object, Object], POSetConflictGraph[Object]) */
+void nit___nit__POSetGroupColorer___graph_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 (graph) <p0:POSetConflictGraph[Object]> isa POSetConflictGraph[H] */
+/* <p0:POSetConflictGraph[Object]> isa POSetConflictGraph[H] */
+type_struct = self->type->resolution_table->types[COLOR_nit__POSetConflictGraph__nit__POSetGroupColorer___35dH];
+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`", "POSetConflictGraph[H]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val = p0; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+RET_LABEL:;
+}
+/* method coloring#POSetGroupColorer#buckets for (self: POSetGroupColorer[Object, Object]): Map[Object, Collection[Object]] */
+val* nit___nit__POSetGroupColorer___buckets(val* self) {
+val* var /* : Map[Object, Collection[Object]] */;
+val* var1 /* : Map[Object, Collection[Object]] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___buckets].val; /* _buckets on <self:POSetGroupColorer[Object, Object]> */
 if (unlikely(var1 == NULL)) {
-PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _buckets");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 288);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
 return var;
 }
-/* method coloring#BucketsColorer#colorize for (self: BucketsColorer[Object, Object], Map[Object, Set[Object]]): Map[Object, Int] */
-val* nit___nit__BucketsColorer___colorize(val* self, val* p0) {
-val* var /* : Map[Object, Int] */;
-short int var1 /* : Bool */;
+/* method coloring#POSetGroupColorer#buckets= for (self: POSetGroupColorer[Object, Object], Map[Object, Collection[Object]]) */
+void nit___nit__POSetGroupColorer___buckets_61d(val* self, val* p0) {
+short int var /* : Bool */;
 int cltype;
 int idtype;
 const struct type* type_struct;
 const char* var_class_name;
-val* var_buckets /* var buckets: Map[Object, Set[Object]] */;
-long var2 /* : Int */;
-long var_min_color /* var min_color: Int */;
-val* var_ /* var : Map[Object, Set[Object]] */;
-val* var3 /* : MapIterator[nullable Object, nullable Object] */;
-val* var_4 /* var : MapIterator[Object, Set[Object]] */;
-short int var5 /* : Bool */;
-val* var6 /* : nullable Object */;
-val* var_holder /* var holder: Object */;
-val* var7 /* : nullable Object */;
-val* var_hbuckets /* var hbuckets: Set[Object] */;
-val* var_8 /* var : Set[Object] */;
-val* var9 /* : Iterator[nullable Object] */;
-val* var_10 /* var : Iterator[Object] */;
-short int var11 /* : Bool */;
-val* var12 /* : nullable Object */;
-val* var_bucket /* var bucket: Object */;
-val* var13 /* : HashMap[Object, Int] */;
-val* var15 /* : HashMap[Object, Int] */;
-short int var16 /* : Bool */;
-long var_color /* var color: Int */;
-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 */;
-val* var28 /* : HashMap[Object, Int] */;
-val* var30 /* : HashMap[Object, Int] */;
-val* var31 /* : nullable Object */;
-val* var36 /* : HashMap[Object, Int] */;
-val* var38 /* : HashMap[Object, Int] */;
-/* Covariant cast for argument 0 (buckets) <p0:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
-/* <p0:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
-type_struct = self->type->resolution_table->types[COLOR_standard__Map__nit__BucketsColorer___35dH__standard__Set__nit__BucketsColorer___35dE];
+/* Covariant cast for argument 0 (buckets) <p0:Map[Object, Collection[Object]]> isa Map[H, Collection[E]] */
+/* <p0:Map[Object, Collection[Object]]> isa Map[H, Collection[E]] */
+type_struct = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetGroupColorer___35dH__standard__Collection__nit__POSetGroupColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
-var1 = 0;
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
+var = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var = (((long)p0&3)?type_info[((long)p0&3)]: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`", "Map[H, Set[E]]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 287);
-show_backtrace(1);
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Collection[E]]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 288);
+fatal_exit(1);
 }
-var_buckets = p0;
+self->attrs[COLOR_nit__coloring__POSetGroupColorer___buckets].val = p0; /* _buckets on <self:POSetGroupColorer[Object, Object]> */
+RET_LABEL:;
+}
+/* method coloring#POSetGroupColorer#poset for (self: POSetGroupColorer[Object, Object]): POSet[Object] */
+val* nit___nit__POSetGroupColorer___poset(val* self) {
+val* var /* : POSet[Object] */;
+val* var1 /* : POSetConflictGraph[Object] */;
+val* var3 /* : POSetConflictGraph[Object] */;
+val* var4 /* : POSet[nullable Object] */;
+val* var6 /* : POSet[nullable Object] */;
 {
-nit___nit__BucketsColorer___compute_conflicts(self, var_buckets); /* Direct call coloring#BucketsColorer#compute_conflicts on <self:BucketsColorer[Object, Object]>*/
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var3 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
 }
-var2 = 0;
-var_min_color = var2;
-var_ = var_buckets;
+var1 = var3;
+RET_LABEL2:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#poset (var1) on <var1:POSetConflictGraph[Object]> */
+var6 = var1->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <var1:POSetConflictGraph[Object]> */
+if (unlikely(var6 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
+fatal_exit(1);
+}
+var4 = var6;
+RET_LABEL5:(void)0;
+}
+}
+var = var4;
+goto RET_LABEL;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#colors for (self: POSetGroupColorer[Object, Object]): Map[Object, Int] */
+val* nit___nit__POSetGroupColorer___colors(val* self) {
+val* var /* : Map[Object, Int] */;
+short int var1 /* : Bool */;
+val* var2 /* : Map[Object, Int] */;
+val* var3 /* : Map[Object, Int] */;
+val* var5 /* : POSetConflictGraph[Object] */;
+val* var7 /* : POSetConflictGraph[Object] */;
+val* var8 /* : POSet[nullable Object] */;
+val* var10 /* : POSet[nullable Object] */;
+val* var_ /* var : POSet[Object] */;
+val* var11 /* : Iterator[nullable Object] */;
+val* var_12 /* var : Iterator[Object] */;
+short int var13 /* : Bool */;
+val* var14 /* : nullable Object */;
+val* var_h /* var h: Object */;
+val* var15 /* : HashMap[Object, HashSet[Int]] */;
+val* var17 /* : HashMap[Object, HashSet[Int]] */;
+val* var18 /* : HashSet[Int] */;
+val* var19 /* : HashMap[Object, Int] */;
+val* var21 /* : HashMap[Object, Int] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors].val != NULL; /* _colors on <self:POSetGroupColorer[Object, Object]> */
+if(likely(var1)) {
+var2 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors].val; /* _colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var2 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 300);
+fatal_exit(1);
+}
+} else {
+{
+{
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var7 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var7 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+var5 = var7;
+RET_LABEL6:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#poset (var5) on <var5:POSetConflictGraph[Object]> */
+var10 = var5->attrs[COLOR_nit__coloring__POSetConflictGraph___poset].val; /* _poset on <var5:POSetConflictGraph[Object]> */
+if (unlikely(var10 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 48);
+fatal_exit(1);
+}
+var8 = var10;
+RET_LABEL9:(void)0;
+}
+}
+var_ = var8;
 {
-var3 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__MapRead__iterator]))(var_) /* iterator on <var_:Map[Object, Set[Object]]>*/;
+var11 = poset___poset__POSet___standard__abstract_collection__Collection__iterator(var_);
 }
-var_4 = var3;
+var_12 = var11;
 for(;;) {
 {
-var5 = ((short int (*)(val* self))(var_4->class->vft[COLOR_standard__abstract_collection__MapIterator__is_ok]))(var_4) /* is_ok on <var_4:MapIterator[Object, Set[Object]]>*/;
+var13 = ((short int(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_12); /* is_ok on <var_12:Iterator[Object]>*/
 }
-if (var5){
+if (var13){
+{
+var14 = ((val*(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_12); /* item on <var_12:Iterator[Object]>*/
+}
+var_h = var14;
+{
+{ /* Inline coloring#POSetGroupColorer#used_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var17 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___used_colors].val; /* _used_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var17 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _used_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 314);
+fatal_exit(1);
+}
+var15 = var17;
+RET_LABEL16:(void)0;
+}
+}
+var18 = NEW_standard__HashSet(&type_standard__HashSet__standard__Int);
+{
+standard___standard__HashSet___standard__kernel__Object__init(var18); /* Direct call hash_collection#HashSet#init on <var18:HashSet[Int]>*/
+}
+{
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var15, var_h, var18); /* Direct call hash_collection#HashMap#[]= on <var15:HashMap[Object, HashSet[Int]]>*/
+}
+{
+((void(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_12); /* next on <var_12:Iterator[Object]>*/
+}
+} else {
+goto BREAK_label;
+}
+}
+BREAK_label: (void)0;
+{
+((void(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_12); /* finish on <var_12:Iterator[Object]>*/
+}
+{
+nit___nit__POSetGroupColorer___compute_colors(self); /* Direct call coloring#POSetGroupColorer#compute_colors on <self:POSetGroupColorer[Object, Object]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#colors_cache (self) on <self:POSetGroupColorer[Object, Object]> */
+var21 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors_cache].val; /* _colors_cache on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var21 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 311);
+fatal_exit(1);
+}
+var19 = var21;
+RET_LABEL20:(void)0;
+}
+}
+var3 = var19;
+goto RET_LABEL4;
+RET_LABEL4:(void)0;
+}
+self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors].val = var3; /* _colors on <self:POSetGroupColorer[Object, Object]> */
+var2 = var3;
+}
+var = var2;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#colors_cache for (self: POSetGroupColorer[Object, Object]): HashMap[Object, Int] */
+val* nit___nit__POSetGroupColorer___colors_cache(val* self) {
+val* var /* : HashMap[Object, Int] */;
+val* var1 /* : HashMap[Object, Int] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors_cache].val; /* _colors_cache on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 311);
+fatal_exit(1);
+}
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#used_colors for (self: POSetGroupColorer[Object, Object]): HashMap[Object, HashSet[Int]] */
+val* nit___nit__POSetGroupColorer___used_colors(val* self) {
+val* var /* : HashMap[Object, HashSet[Int]] */;
+val* var1 /* : HashMap[Object, HashSet[Int]] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___used_colors].val; /* _used_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _used_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 314);
+fatal_exit(1);
+}
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#build_layout for (self: POSetGroupColorer[Object, Object], Object): Array[nullable Object] */
+val* nit___nit__POSetGroupColorer___build_layout(val* self, val* p0) {
+val* var /* : Array[nullable Object] */;
+short int var1 /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+val* var_h /* var h: Object */;
+val* var2 /* : Array[nullable Object] */;
+val* var_table /* var table: Array[nullable Object] */;
+val* var3 /* : POSet[Object] */;
+val* var4 /* : POSetElement[nullable Object] */;
+val* var5 /* : Collection[nullable Object] */;
+val* var_ /* var : Collection[Object] */;
+val* var6 /* : Iterator[nullable Object] */;
+val* var_7 /* var : Iterator[Object] */;
+short int var8 /* : Bool */;
+val* var9 /* : nullable Object */;
+val* var_s /* var s: Object */;
+val* var10 /* : Map[Object, Collection[Object]] */;
+val* var12 /* : Map[Object, Collection[Object]] */;
+val* var13 /* : nullable Object */;
+val* var_bucket /* var bucket: nullable Collection[Object] */;
+short int var14 /* : Bool */;
+short int var15 /* : Bool */;
+val* var_16 /* var : Collection[Object] */;
+val* var17 /* : Iterator[nullable Object] */;
+val* var_18 /* var : Iterator[Object] */;
+short int var19 /* : Bool */;
+val* var20 /* : nullable Object */;
+val* var_e /* var e: Object */;
+val* var21 /* : Map[Object, Int] */;
+val* var22 /* : nullable Object */;
+long var23 /* : Int */;
+long var_color /* var color: Int */;
+long var24 /* : Int */;
+long var26 /* : Int */;
+short int var27 /* : Bool */;
+short int var29 /* : Bool */;
+int cltype30;
+int idtype31;
+const char* var_class_name32;
+short int var33 /* : Bool */;
+long var34 /* : Int */;
+long var36 /* : Int */;
+long var_i /* var i: Int */;
+long var_37 /* var : Int */;
+short int var38 /* : Bool */;
+short int var40 /* : Bool */;
+int cltype41;
+int idtype42;
+const char* var_class_name43;
+short int var44 /* : Bool */;
+long var45 /* : Int */;
+val* var47 /* : nullable Object */;
+short int var48 /* : Bool */;
+short int var49 /* : Bool */;
+val* var50 /* : Sys */;
+val* var51 /* : NativeArray[String] */;
+static val* varonce;
+static val* varonce52;
+val* var53 /* : String */;
+char* var54 /* : NativeString */;
+val* var55 /* : FlatString */;
+static val* varonce56;
+val* var57 /* : String */;
+char* var58 /* : NativeString */;
+val* var59 /* : FlatString */;
+static val* varonce60;
+val* var61 /* : String */;
+char* var62 /* : NativeString */;
+val* var63 /* : FlatString */;
+static val* varonce64;
+val* var65 /* : String */;
+char* var66 /* : NativeString */;
+val* var67 /* : FlatString */;
+val* var68 /* : String */;
+val* var69 /* : String */;
+val* var70 /* : Object */;
+val* var71 /* : nullable Object */;
+static val* varonce72;
+val* var73 /* : String */;
+char* var74 /* : NativeString */;
+val* var75 /* : FlatString */;
+val* var76 /* : String */;
+val* var77 /* : String */;
+val* var78 /* : String */;
+/* Covariant cast for argument 0 (h) <p0:Object> isa H */
+/* <p0:Object> isa H */
+type_struct = self->type->resolution_table->types[COLOR_nit__POSetGroupColorer___35dH];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
+var1 = 0;
+} else {
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
+}
+if (unlikely(!var1)) {
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "H", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 317);
+fatal_exit(1);
+}
+var_h = p0;
+var2 = NEW_standard__Array(self->type->resolution_table->types[COLOR_standard__Array__nullable__nit__POSetGroupColorer___35dE]);
+{
+standard___standard__Array___standard__kernel__Object__init(var2); /* Direct call array#Array#init on <var2:Array[nullable Object]>*/
+}
+var_table = var2;
+{
+var3 = nit___nit__POSetGroupColorer___poset(self);
+}
+{
+var4 = poset___poset__POSet____91d_93d(var3, var_h);
+}
+{
+var5 = poset___poset__POSetElement___greaters(var4);
+}
+var_ = var5;
+{
+var6 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[Object]>*/
+}
+var_7 = var6;
+for(;;) {
+{
+var8 = ((short int(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_7); /* is_ok on <var_7:Iterator[Object]>*/
+}
+if (var8){
+{
+var9 = ((val*(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_7); /* item on <var_7:Iterator[Object]>*/
+}
+var_s = var9;
+{
+{ /* Inline coloring#POSetGroupColorer#buckets (self) on <self:POSetGroupColorer[Object, Object]> */
+var12 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___buckets].val; /* _buckets on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var12 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _buckets");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 288);
+fatal_exit(1);
+}
+var10 = var12;
+RET_LABEL11:(void)0;
+}
+}
+{
+var13 = ((val*(*)(val* self, val* p0))((((long)var10&3)?class_info[((long)var10&3)]:var10->class)->vft[COLOR_standard__abstract_collection__MapRead__get_or_null]))(var10, var_s); /* get_or_null on <var10:Map[Object, Collection[Object]]>*/
+}
+var_bucket = var13;
+if (var_bucket == NULL) {
+var14 = 1; /* is null */
+} else {
+var14 = 0; /* arg is null but recv is not */
+}
+if (0) {
+var15 = ((short int(*)(val* self, val* p0))((((long)var_bucket&3)?class_info[((long)var_bucket&3)]:var_bucket->class)->vft[COLOR_standard__kernel__Object___61d_61d]))(var_bucket, ((val*)NULL)); /* == on <var_bucket:nullable Collection[Object]>*/
+var14 = var15;
+}
+if (var14){
+goto BREAK_label;
+} else {
+}
+var_16 = var_bucket;
+{
+var17 = ((val*(*)(val* self))((((long)var_16&3)?class_info[((long)var_16&3)]:var_16->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_16); /* iterator on <var_16:Collection[Object]>*/
+}
+var_18 = var17;
+for(;;) {
+{
+var19 = ((short int(*)(val* self))((((long)var_18&3)?class_info[((long)var_18&3)]:var_18->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_18); /* is_ok on <var_18:Iterator[Object]>*/
+}
+if (var19){
+{
+var20 = ((val*(*)(val* self))((((long)var_18&3)?class_info[((long)var_18&3)]:var_18->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_18); /* item on <var_18:Iterator[Object]>*/
+}
+var_e = var20;
+{
+var21 = nit___nit__POSetGroupColorer___colors(self);
+}
+{
+var22 = ((val*(*)(val* self, val* p0))((((long)var21&3)?class_info[((long)var21&3)]:var21->class)->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var21, var_e); /* [] on <var21:Map[Object, Int]>*/
+}
+var23 = (long)(var22)>>2;
+var_color = var23;
+{
+{ /* Inline array#AbstractArrayRead#length (var_table) on <var_table:Array[nullable Object]> */
+var26 = var_table->attrs[COLOR_standard__array__AbstractArrayRead___length].l; /* _length on <var_table:Array[nullable Object]> */
+var24 = var26;
+RET_LABEL25:(void)0;
+}
+}
+{
+{ /* Inline kernel#Int#<= (var24,var_color) on <var24:Int> */
+/* Covariant cast for argument 0 (i) <var_color:Int> isa OTHER */
+/* <var_color:Int> isa OTHER */
+var29 = 1; /* easy <var_color:Int> isa OTHER*/
+if (unlikely(!var29)) {
+var_class_name32 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name32);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 533);
+fatal_exit(1);
+}
+var33 = var24 <= var_color;
+var27 = var33;
+goto RET_LABEL28;
+RET_LABEL28:(void)0;
+}
+}
+if (var27){
+{
+{ /* Inline array#AbstractArrayRead#length (var_table) on <var_table:Array[nullable Object]> */
+var36 = var_table->attrs[COLOR_standard__array__AbstractArrayRead___length].l; /* _length on <var_table:Array[nullable Object]> */
+var34 = var36;
+RET_LABEL35:(void)0;
+}
+}
+var_i = var34;
+var_37 = var_color;
+for(;;) {
+{
+{ /* Inline kernel#Int#< (var_i,var_37) on <var_i:Int> */
+/* Covariant cast for argument 0 (i) <var_37:Int> isa OTHER */
+/* <var_37:Int> isa OTHER */
+var40 = 1; /* easy <var_37:Int> isa OTHER*/
+if (unlikely(!var40)) {
+var_class_name43 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name43);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 534);
+fatal_exit(1);
+}
+var44 = var_i < var_37;
+var38 = var44;
+goto RET_LABEL39;
+RET_LABEL39:(void)0;
+}
+}
+if (var38){
+{
+standard___standard__Array___standard__abstract_collection__Sequence___91d_93d_61d(var_table, var_i, ((val*)NULL)); /* Direct call array#Array#[]= on <var_table:Array[nullable Object]>*/
+}
+{
+var45 = standard___standard__Int___Discrete__successor(var_i, 1l);
+}
+var_i = var45;
+} else {
+goto BREAK_label46;
+}
+}
+BREAK_label46: (void)0;
+} else {
+{
+var47 = standard___standard__Array___standard__abstract_collection__SequenceRead___91d_93d(var_table, var_color);
+}
+if (var47 == NULL) {
+var48 = 1; /* is null */
+} else {
+var48 = 0; /* arg is null but recv is not */
+}
+if (0) {
+var49 = ((short int(*)(val* self, val* p0))((((long)var47&3)?class_info[((long)var47&3)]:var47->class)->vft[COLOR_standard__kernel__Object___61d_61d]))(var47, ((val*)NULL)); /* == on <var47:nullable Object>*/
+var48 = var49;
+}
+if (unlikely(!var48)) {
+var50 = glob_sys;
+if (unlikely(varonce==NULL)) {
+var51 = NEW_standard__NativeArray(8l, &type_standard__NativeArray__standard__String);
+if (likely(varonce52!=NULL)) {
+var53 = varonce52;
+} else {
+var54 = "in ";
+var55 = standard___standard__NativeString___to_s_with_length(var54, 3l);
+var53 = var55;
+varonce52 = var53;
+}
+((struct instance_standard__NativeArray*)var51)->values[0]=var53;
+if (likely(varonce56!=NULL)) {
+var57 = varonce56;
+} else {
+var58 = ", for ";
+var59 = standard___standard__NativeString___to_s_with_length(var58, 6l);
+var57 = var59;
+varonce56 = var57;
+}
+((struct instance_standard__NativeArray*)var51)->values[2]=var57;
+if (likely(varonce60!=NULL)) {
+var61 = varonce60;
+} else {
+var62 = ": ";
+var63 = standard___standard__NativeString___to_s_with_length(var62, 2l);
+var61 = var63;
+varonce60 = var61;
+}
+((struct instance_standard__NativeArray*)var51)->values[4]=var61;
+if (likely(varonce64!=NULL)) {
+var65 = varonce64;
+} else {
+var66 = " vs ";
+var67 = standard___standard__NativeString___to_s_with_length(var66, 4l);
+var65 = var67;
+varonce64 = var65;
+}
+((struct instance_standard__NativeArray*)var51)->values[6]=var65;
+} else {
+var51 = varonce;
+varonce = NULL;
+}
+{
+var68 = ((val*(*)(val* self))((((long)var_h&3)?class_info[((long)var_h&3)]:var_h->class)->vft[COLOR_standard__string__Object__to_s]))(var_h); /* to_s on <var_h:Object>*/
+}
+((struct instance_standard__NativeArray*)var51)->values[1]=var68;
+var69 = standard__string___Int___Object__to_s(var_color);
+((struct instance_standard__NativeArray*)var51)->values[3]=var69;
+{
+var71 = standard___standard__Array___standard__abstract_collection__SequenceRead___91d_93d(var_table, var_color);
+}
+if (var71!=NULL) {
+var70 = var71;
+} else {
+if (likely(varonce72!=NULL)) {
+var73 = varonce72;
+} else {
+var74 = "";
+var75 = standard___standard__NativeString___to_s_with_length(var74, 0l);
+var73 = var75;
+varonce72 = var73;
+}
+var70 = var73;
+}
+{
+var76 = ((val*(*)(val* self))((((long)var70&3)?class_info[((long)var70&3)]:var70->class)->vft[COLOR_standard__string__Object__to_s]))(var70); /* to_s on <var70:Object>*/
+}
+((struct instance_standard__NativeArray*)var51)->values[5]=var76;
+{
+var77 = ((val*(*)(val* self))((((long)var_e&3)?class_info[((long)var_e&3)]:var_e->class)->vft[COLOR_standard__string__Object__to_s]))(var_e); /* to_s on <var_e:Object>*/
+}
+((struct instance_standard__NativeArray*)var51)->values[7]=var77;
+{
+var78 = ((val*(*)(val* self))(var51->class->vft[COLOR_standard__string__NativeArray__native_to_s]))(var51); /* native_to_s on <var51:NativeArray[String]>*/
+}
+varonce = var51;
+{
+standard__file___Sys___print(var50, var78); /* Direct call file#Sys#print on <var50:Sys>*/
+}
+PRINT_ERROR("Runtime error: %s", "Assert failed");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 333);
+fatal_exit(1);
+}
+}
+{
+standard___standard__Array___standard__abstract_collection__Sequence___91d_93d_61d(var_table, var_color, var_e); /* Direct call array#Array#[]= on <var_table:Array[nullable Object]>*/
+}
+{
+((void(*)(val* self))((((long)var_18&3)?class_info[((long)var_18&3)]:var_18->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_18); /* next on <var_18:Iterator[Object]>*/
+}
+} else {
+goto BREAK_label79;
+}
+}
+BREAK_label79: (void)0;
+{
+((void(*)(val* self))((((long)var_18&3)?class_info[((long)var_18&3)]:var_18->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_18); /* finish on <var_18:Iterator[Object]>*/
+}
+BREAK_label: (void)0;
+{
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_7); /* next on <var_7:Iterator[Object]>*/
+}
+} else {
+goto BREAK_label80;
+}
+}
+BREAK_label80: (void)0;
+{
+((void(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_7); /* finish on <var_7:Iterator[Object]>*/
+}
+var = var_table;
+goto RET_LABEL;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#compute_colors for (self: POSetGroupColorer[Object, Object]) */
+void nit___nit__POSetGroupColorer___compute_colors(val* self) {
+val* var /* : HashMap[Object, Int] */;
+val* var2 /* : HashMap[Object, Int] */;
+val* var3 /* : POSetConflictGraph[Object] */;
+val* var5 /* : POSetConflictGraph[Object] */;
+val* var6 /* : HashSet[nullable Object] */;
+val* var8 /* : HashSet[nullable Object] */;
+val* var9 /* : POSetConflictGraph[Object] */;
+val* var11 /* : POSetConflictGraph[Object] */;
+val* var12 /* : HashSet[nullable Object] */;
+val* var14 /* : HashSet[nullable Object] */;
+{
+{ /* Inline coloring#POSetGroupColorer#colors_cache (self) on <self:POSetGroupColorer[Object, Object]> */
+var2 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors_cache].val; /* _colors_cache on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var2 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 311);
+fatal_exit(1);
+}
+var = var2;
+RET_LABEL1:(void)0;
+}
+}
+{
+standard___standard__HashMap___standard__abstract_collection__Map__clear(var); /* Direct call hash_collection#HashMap#clear on <var:HashMap[Object, Int]>*/
+}
+{
+nit___nit__POSetGroupColorer___colorize_core(self); /* Direct call coloring#POSetGroupColorer#colorize_core on <self:POSetGroupColorer[Object, Object]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var5 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var5 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+var3 = var5;
+RET_LABEL4:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#border (var3) on <var3:POSetConflictGraph[Object]> */
+var8 = var3->attrs[COLOR_nit__coloring__POSetConflictGraph___border].val; /* _border on <var3:POSetConflictGraph[Object]> */
+if (unlikely(var8 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _border");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 28);
+fatal_exit(1);
+}
+var6 = var8;
+RET_LABEL7:(void)0;
+}
+}
+{
+nit___nit__POSetGroupColorer___colorize_set(self, var6); /* Direct call coloring#POSetGroupColorer#colorize_set on <self:POSetGroupColorer[Object, Object]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var11 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var11 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+var9 = var11;
+RET_LABEL10:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#crown (var9) on <var9:POSetConflictGraph[Object]> */
+var14 = var9->attrs[COLOR_nit__coloring__POSetConflictGraph___crown].val; /* _crown on <var9:POSetConflictGraph[Object]> */
+if (unlikely(var14 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _crown");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 34);
+fatal_exit(1);
+}
+var12 = var14;
+RET_LABEL13:(void)0;
+}
+}
+{
+nit___nit__POSetGroupColorer___colorize_set(self, var12); /* Direct call coloring#POSetGroupColorer#colorize_set on <self:POSetGroupColorer[Object, Object]>*/
+}
+RET_LABEL:;
+}
+/* method coloring#POSetGroupColorer#colorize_core for (self: POSetGroupColorer[Object, Object]) */
+void nit___nit__POSetGroupColorer___colorize_core(val* self) {
+val* var /* : POSetConflictGraph[Object] */;
+val* var2 /* : POSetConflictGraph[Object] */;
+val* var3 /* : Array[nullable Object] */;
+val* var5 /* : Array[nullable Object] */;
+val* var_ /* var : Array[Object] */;
+val* var6 /* : ArrayIterator[nullable Object] */;
+val* var_7 /* var : ArrayIterator[Object] */;
+short int var8 /* : Bool */;
+val* var9 /* : nullable Object */;
+val* var_h /* var h: Object */;
+val* var10 /* : POSetConflictGraph[Object] */;
+val* var12 /* : POSetConflictGraph[Object] */;
+val* var13 /* : HashSet[nullable Object] */;
+val* var15 /* : HashSet[nullable Object] */;
+short int var16 /* : Bool */;
+short int var17 /* : Bool */;
+long var18 /* : Int */;
+long var_color /* var color: Int */;
+long var_mincolor /* var mincolor: Int */;
+val* var19 /* : Map[Object, Collection[Object]] */;
+val* var21 /* : Map[Object, Collection[Object]] */;
+val* var22 /* : nullable Object */;
+val* var_bucket /* var bucket: nullable Collection[Object] */;
+short int var23 /* : Bool */;
+short int var24 /* : Bool */;
+val* var25 /* : POSetConflictGraph[Object] */;
+val* var27 /* : POSetConflictGraph[Object] */;
+val* var28 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var30 /* : HashMap[nullable Object, Set[nullable Object]] */;
+val* var31 /* : nullable Object */;
+val* var_conflicts /* var conflicts: Set[Object] */;
+val* var32 /* : POSet[Object] */;
+val* var33 /* : POSetElement[nullable Object] */;
+val* var34 /* : Collection[nullable Object] */;
+val* var_parents /* var parents: Collection[Object] */;
+val* var_35 /* var : Collection[Object] */;
+val* var36 /* : Iterator[nullable Object] */;
+val* var_37 /* var : Iterator[Object] */;
+short int var38 /* : Bool */;
+val* var39 /* : nullable Object */;
+val* var_e /* var e: Object */;
+long var40 /* : Int */;
+long var41 /* : Int */;
+val* var42 /* : HashMap[Object, Int] */;
+val* var44 /* : HashMap[Object, Int] */;
+val* var45 /* : nullable Object */;
+val* var46 /* : HashMap[Object, HashSet[Int]] */;
+val* var48 /* : HashMap[Object, HashSet[Int]] */;
+val* var49 /* : nullable Object */;
+val* var50 /* : nullable Object */;
+short int var51 /* : Bool */;
+short int var53 /* : Bool */;
+long var54 /* : Int */;
+short int var56 /* : Bool */;
+int cltype;
+int idtype;
+const char* var_class_name;
+long var57 /* : Int */;
+long var58 /* : Int */;
+short int var60 /* : Bool */;
+int cltype61;
+int idtype62;
+const char* var_class_name63;
+long var64 /* : Int */;
+val* var66 /* : HashMap[Object, Int] */;
+val* var68 /* : HashMap[Object, Int] */;
+val* var69 /* : nullable Object */;
+{
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var2 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var2 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+var = var2;
+RET_LABEL1:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#order (var) on <var:POSetConflictGraph[Object]> */
+var5 = var->attrs[COLOR_nit__coloring__POSetConflictGraph___order].val; /* _order on <var:POSetConflictGraph[Object]> */
+if (unlikely(var5 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _order");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 51);
+fatal_exit(1);
+}
+var3 = var5;
+RET_LABEL4:(void)0;
+}
+}
+var_ = var3;
+{
+var6 = standard___standard__AbstractArrayRead___standard__abstract_collection__Collection__iterator(var_);
+}
+var_7 = var6;
+for(;;) {
+{
+var8 = standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__is_ok(var_7);
+}
+if (var8){
+{
+var9 = standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__item(var_7);
+}
+var_h = var9;
+{
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var12 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var12 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+var10 = var12;
+RET_LABEL11:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#core (var10) on <var10:POSetConflictGraph[Object]> */
+var15 = var10->attrs[COLOR_nit__coloring__POSetConflictGraph___core].val; /* _core on <var10:POSetConflictGraph[Object]> */
+if (unlikely(var15 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _core");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 22);
+fatal_exit(1);
+}
+var13 = var15;
+RET_LABEL14:(void)0;
+}
+}
+{
+var16 = standard___standard__HashSet___standard__abstract_collection__Collection__has(var13, var_h);
+}
+var17 = !var16;
+if (var17){
+goto BREAK_label;
+} else {
+}
+{
+var18 = nit___nit__POSetGroupColorer___inherit_color(self, var_h);
+}
+var_color = var18;
+var_mincolor = var_color;
+{
+{ /* Inline coloring#POSetGroupColorer#buckets (self) on <self:POSetGroupColorer[Object, Object]> */
+var21 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___buckets].val; /* _buckets on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var21 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _buckets");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 288);
+fatal_exit(1);
+}
+var19 = var21;
+RET_LABEL20:(void)0;
+}
+}
+{
+var22 = ((val*(*)(val* self, val* p0))((((long)var19&3)?class_info[((long)var19&3)]:var19->class)->vft[COLOR_standard__abstract_collection__MapRead__get_or_null]))(var19, var_h); /* get_or_null on <var19:Map[Object, Collection[Object]]>*/
+}
+var_bucket = var22;
+if (var_bucket == NULL) {
+var23 = 1; /* is null */
+} else {
+var23 = 0; /* arg is null but recv is not */
+}
+if (0) {
+var24 = ((short int(*)(val* self, val* p0))((((long)var_bucket&3)?class_info[((long)var_bucket&3)]:var_bucket->class)->vft[COLOR_standard__kernel__Object___61d_61d]))(var_bucket, ((val*)NULL)); /* == on <var_bucket:nullable Collection[Object]>*/
+var23 = var24;
+}
+if (var23){
+goto BREAK_label;
+} else {
+}
+{
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var27 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var27 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+var25 = var27;
+RET_LABEL26:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#conflicts (var25) on <var25:POSetConflictGraph[Object]> */
+var30 = var25->attrs[COLOR_nit__coloring__POSetConflictGraph___conflicts].val; /* _conflicts on <var25:POSetConflictGraph[Object]> */
+if (unlikely(var30 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 40);
+fatal_exit(1);
+}
+var28 = var30;
+RET_LABEL29:(void)0;
+}
+}
+{
+var31 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var28, var_h);
+}
+var_conflicts = var31;
+{
+var32 = nit___nit__POSetGroupColorer___poset(self);
+}
+{
+var33 = poset___poset__POSet____91d_93d(var32, var_h);
+}
+{
+var34 = poset___poset__POSetElement___greaters(var33);
+}
+var_parents = var34;
+var_35 = var_bucket;
+{
+var36 = ((val*(*)(val* self))((((long)var_35&3)?class_info[((long)var_35&3)]:var_35->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_35); /* iterator on <var_35:Collection[Object]>*/
+}
+var_37 = var36;
+for(;;) {
+{
+var38 = ((short int(*)(val* self))((((long)var_37&3)?class_info[((long)var_37&3)]:var_37->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_37); /* is_ok on <var_37:Iterator[Object]>*/
+}
+if (var38){
+{
+var39 = ((val*(*)(val* self))((((long)var_37&3)?class_info[((long)var_37&3)]:var_37->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_37); /* item on <var_37:Iterator[Object]>*/
+}
+var_e = var39;
+{
+var40 = nit___nit__POSetGroupColorer___next_free_color(self, var_color, var_parents);
+}
+var_color = var40;
+{
+var41 = nit___nit__POSetGroupColorer___next_free_color(self, var_color, var_conflicts);
+}
+var_color = var41;
+{
+{ /* Inline coloring#POSetGroupColorer#colors_cache (self) on <self:POSetGroupColorer[Object, Object]> */
+var44 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors_cache].val; /* _colors_cache on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var44 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 311);
+fatal_exit(1);
+}
+var42 = var44;
+RET_LABEL43:(void)0;
+}
+}
+{
+var45 = (val*)(var_color<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var42, var_e, var45); /* Direct call hash_collection#HashMap#[]= on <var42:HashMap[Object, Int]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#used_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var48 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___used_colors].val; /* _used_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var48 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _used_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 314);
+fatal_exit(1);
+}
+var46 = var48;
+RET_LABEL47:(void)0;
+}
+}
+{
+var49 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var46, var_h);
+}
+{
+var50 = (val*)(var_color<<2|1);
+standard___standard__HashSet___standard__abstract_collection__SimpleCollection__add(var49, var50); /* Direct call hash_collection#HashSet#add on <var49:nullable Object(HashSet[Int])>*/
+}
+{
+{ /* Inline kernel#Int#== (var_mincolor,var_color) on <var_mincolor:Int> */
+var53 = var_mincolor == var_color;
+var51 = var53;
+goto RET_LABEL52;
+RET_LABEL52:(void)0;
+}
+}
+if (var51){
+{
+{ /* Inline kernel#Int#+ (var_mincolor,1l) on <var_mincolor:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var56 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var56)) {
+var_class_name = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var57 = var_mincolor + 1l;
+var54 = var57;
+goto RET_LABEL55;
+RET_LABEL55:(void)0;
+}
+}
+var_mincolor = var54;
+} else {
+}
+{
+{ /* Inline kernel#Int#+ (var_color,1l) on <var_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var60 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var60)) {
+var_class_name63 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name63);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var64 = var_color + 1l;
+var58 = var64;
+goto RET_LABEL59;
+RET_LABEL59:(void)0;
+}
+}
+var_color = var58;
+{
+((void(*)(val* self))((((long)var_37&3)?class_info[((long)var_37&3)]:var_37->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_37); /* next on <var_37:Iterator[Object]>*/
+}
+} else {
+goto BREAK_label65;
+}
+}
+BREAK_label65: (void)0;
+{
+((void(*)(val* self))((((long)var_37&3)?class_info[((long)var_37&3)]:var_37->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_37); /* finish on <var_37:Iterator[Object]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#min_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var68 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___min_colors].val; /* _min_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var68 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _min_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 409);
+fatal_exit(1);
+}
+var66 = var68;
+RET_LABEL67:(void)0;
+}
+}
+{
+var69 = (val*)(var_mincolor<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var66, var_h, var69); /* Direct call hash_collection#HashMap#[]= on <var66:HashMap[Object, Int]>*/
+}
+BREAK_label: (void)0;
+{
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__next(var_7); /* Direct call array#ArrayIterator#next on <var_7:ArrayIterator[Object]>*/
+}
+} else {
+goto BREAK_label70;
+}
+}
+BREAK_label70: (void)0;
+{
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__finish(var_7); /* Direct call array#ArrayIterator#finish on <var_7:ArrayIterator[Object]>*/
+}
+RET_LABEL:;
+}
+/* method coloring#POSetGroupColorer#colorize_set for (self: POSetGroupColorer[Object, Object], Set[Object]) */
+void nit___nit__POSetGroupColorer___colorize_set(val* self, val* p0) {
+short int var /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+val* var_set /* var set: Set[Object] */;
+val* var1 /* : POSetConflictGraph[Object] */;
+val* var3 /* : POSetConflictGraph[Object] */;
+val* var4 /* : Array[nullable Object] */;
+val* var6 /* : Array[nullable Object] */;
+val* var_ /* var : Array[Object] */;
+val* var7 /* : ArrayIterator[nullable Object] */;
+val* var_8 /* var : ArrayIterator[Object] */;
+short int var9 /* : Bool */;
+val* var10 /* : nullable Object */;
+val* var_h /* var h: Object */;
+short int var11 /* : Bool */;
+short int var12 /* : Bool */;
+long var13 /* : Int */;
+long var_color /* var color: Int */;
+long var_mincolor /* var mincolor: Int */;
+val* var14 /* : Map[Object, Collection[Object]] */;
+val* var16 /* : Map[Object, Collection[Object]] */;
+val* var17 /* : nullable Object */;
+val* var_bucket /* var bucket: nullable Collection[Object] */;
+short int var18 /* : Bool */;
+short int var19 /* : Bool */;
+val* var20 /* : POSet[Object] */;
+val* var21 /* : POSetElement[nullable Object] */;
+val* var22 /* : Collection[nullable Object] */;
+val* var_parents /* var parents: Collection[Object] */;
+val* var_23 /* var : Collection[Object] */;
+val* var24 /* : Iterator[nullable Object] */;
+val* var_25 /* var : Iterator[Object] */;
+short int var26 /* : Bool */;
+val* var27 /* : nullable Object */;
+val* var_e /* var e: Object */;
+long var28 /* : Int */;
+val* var29 /* : HashMap[Object, Int] */;
+val* var31 /* : HashMap[Object, Int] */;
+val* var32 /* : nullable Object */;
+val* var33 /* : HashMap[Object, HashSet[Int]] */;
+val* var35 /* : HashMap[Object, HashSet[Int]] */;
+val* var36 /* : nullable Object */;
+val* var37 /* : nullable Object */;
+short int var38 /* : Bool */;
+short int var40 /* : Bool */;
+long var41 /* : Int */;
+short int var43 /* : Bool */;
+int cltype44;
+int idtype45;
+const char* var_class_name46;
+long var47 /* : Int */;
+long var48 /* : Int */;
+short int var50 /* : Bool */;
+int cltype51;
+int idtype52;
+const char* var_class_name53;
+long var54 /* : Int */;
+val* var56 /* : HashMap[Object, Int] */;
+val* var58 /* : HashMap[Object, Int] */;
+val* var59 /* : nullable Object */;
+/* Covariant cast for argument 0 (set) <p0:Set[Object]> isa Set[H] */
+/* <p0:Set[Object]> isa Set[H] */
+type_struct = self->type->resolution_table->types[COLOR_standard__Set__nit__POSetGroupColorer___35dH];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
+var = 0;
+} else {
+var = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
+}
+if (unlikely(!var)) {
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Set[H]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 375);
+fatal_exit(1);
+}
+var_set = p0;
+{
+{ /* Inline coloring#POSetGroupColorer#graph (self) on <self:POSetGroupColorer[Object, Object]> */
+var3 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___graph].val; /* _graph on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var3 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _graph");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 282);
+fatal_exit(1);
+}
+var1 = var3;
+RET_LABEL2:(void)0;
+}
+}
+{
+{ /* Inline coloring#POSetConflictGraph#order (var1) on <var1:POSetConflictGraph[Object]> */
+var6 = var1->attrs[COLOR_nit__coloring__POSetConflictGraph___order].val; /* _order on <var1:POSetConflictGraph[Object]> */
+if (unlikely(var6 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _order");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 51);
+fatal_exit(1);
+}
+var4 = var6;
+RET_LABEL5:(void)0;
+}
+}
+var_ = var4;
+{
+var7 = standard___standard__AbstractArrayRead___standard__abstract_collection__Collection__iterator(var_);
+}
+var_8 = var7;
+for(;;) {
+{
+var9 = standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__is_ok(var_8);
+}
+if (var9){
+{
+var10 = standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__item(var_8);
+}
+var_h = var10;
+{
+var11 = ((short int(*)(val* self, val* p0))((((long)var_set&3)?class_info[((long)var_set&3)]:var_set->class)->vft[COLOR_standard__abstract_collection__Collection__has]))(var_set, var_h); /* has on <var_set:Set[Object]>*/
+}
+var12 = !var11;
+if (var12){
+goto BREAK_label;
+} else {
+}
+{
+var13 = nit___nit__POSetGroupColorer___inherit_color(self, var_h);
+}
+var_color = var13;
+var_mincolor = var_color;
+{
+{ /* Inline coloring#POSetGroupColorer#buckets (self) on <self:POSetGroupColorer[Object, Object]> */
+var16 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___buckets].val; /* _buckets on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var16 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _buckets");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 288);
+fatal_exit(1);
+}
+var14 = var16;
+RET_LABEL15:(void)0;
+}
+}
+{
+var17 = ((val*(*)(val* self, val* p0))((((long)var14&3)?class_info[((long)var14&3)]:var14->class)->vft[COLOR_standard__abstract_collection__MapRead__get_or_null]))(var14, var_h); /* get_or_null on <var14:Map[Object, Collection[Object]]>*/
+}
+var_bucket = var17;
+if (var_bucket == NULL) {
+var18 = 1; /* is null */
+} else {
+var18 = 0; /* arg is null but recv is not */
+}
+if (0) {
+var19 = ((short int(*)(val* self, val* p0))((((long)var_bucket&3)?class_info[((long)var_bucket&3)]:var_bucket->class)->vft[COLOR_standard__kernel__Object___61d_61d]))(var_bucket, ((val*)NULL)); /* == on <var_bucket:nullable Collection[Object]>*/
+var18 = var19;
+}
+if (var18){
+goto BREAK_label;
+} else {
+}
+{
+var20 = nit___nit__POSetGroupColorer___poset(self);
+}
+{
+var21 = poset___poset__POSet____91d_93d(var20, var_h);
+}
+{
+var22 = poset___poset__POSetElement___greaters(var21);
+}
+var_parents = var22;
+var_23 = var_bucket;
+{
+var24 = ((val*(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_23); /* iterator on <var_23:Collection[Object]>*/
+}
+var_25 = var24;
+for(;;) {
+{
+var26 = ((short int(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_25); /* is_ok on <var_25:Iterator[Object]>*/
+}
+if (var26){
+{
+var27 = ((val*(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_25); /* item on <var_25:Iterator[Object]>*/
+}
+var_e = var27;
+{
+var28 = nit___nit__POSetGroupColorer___next_free_color(self, var_color, var_parents);
+}
+var_color = var28;
+{
+{ /* Inline coloring#POSetGroupColorer#colors_cache (self) on <self:POSetGroupColorer[Object, Object]> */
+var31 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___colors_cache].val; /* _colors_cache on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var31 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors_cache");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 311);
+fatal_exit(1);
+}
+var29 = var31;
+RET_LABEL30:(void)0;
+}
+}
+{
+var32 = (val*)(var_color<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var29, var_e, var32); /* Direct call hash_collection#HashMap#[]= on <var29:HashMap[Object, Int]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#used_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var35 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___used_colors].val; /* _used_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var35 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _used_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 314);
+fatal_exit(1);
+}
+var33 = var35;
+RET_LABEL34:(void)0;
+}
+}
+{
+var36 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var33, var_h);
+}
+{
+var37 = (val*)(var_color<<2|1);
+standard___standard__HashSet___standard__abstract_collection__SimpleCollection__add(var36, var37); /* Direct call hash_collection#HashSet#add on <var36:nullable Object(HashSet[Int])>*/
+}
+{
+{ /* Inline kernel#Int#== (var_mincolor,var_color) on <var_mincolor:Int> */
+var40 = var_mincolor == var_color;
+var38 = var40;
+goto RET_LABEL39;
+RET_LABEL39:(void)0;
+}
+}
+if (var38){
+{
+{ /* Inline kernel#Int#+ (var_mincolor,1l) on <var_mincolor:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var43 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var43)) {
+var_class_name46 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name46);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var47 = var_mincolor + 1l;
+var41 = var47;
+goto RET_LABEL42;
+RET_LABEL42:(void)0;
+}
+}
+var_mincolor = var41;
+} else {
+}
+{
+{ /* Inline kernel#Int#+ (var_color,1l) on <var_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var50 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var50)) {
+var_class_name53 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name53);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var54 = var_color + 1l;
+var48 = var54;
+goto RET_LABEL49;
+RET_LABEL49:(void)0;
+}
+}
+var_color = var48;
+{
+((void(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_25); /* next on <var_25:Iterator[Object]>*/
+}
+} else {
+goto BREAK_label55;
+}
+}
+BREAK_label55: (void)0;
+{
+((void(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_25); /* finish on <var_25:Iterator[Object]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#min_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var58 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___min_colors].val; /* _min_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var58 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _min_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 409);
+fatal_exit(1);
+}
+var56 = var58;
+RET_LABEL57:(void)0;
+}
+}
+{
+var59 = (val*)(var_mincolor<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var56, var_h, var59); /* Direct call hash_collection#HashMap#[]= on <var56:HashMap[Object, Int]>*/
+}
+BREAK_label: (void)0;
+{
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__next(var_8); /* Direct call array#ArrayIterator#next on <var_8:ArrayIterator[Object]>*/
+}
+} else {
+goto BREAK_label60;
+}
+}
+BREAK_label60: (void)0;
+{
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__finish(var_8); /* Direct call array#ArrayIterator#finish on <var_8:ArrayIterator[Object]>*/
+}
+RET_LABEL:;
+}
+/* method coloring#POSetGroupColorer#inherit_color for (self: POSetGroupColorer[Object, Object], Object): Int */
+long nit___nit__POSetGroupColorer___inherit_color(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_h /* var h: Object */;
+long var_res /* var res: Int */;
+val* var2 /* : POSet[Object] */;
+val* var3 /* : POSetElement[nullable Object] */;
+val* var4 /* : Collection[nullable Object] */;
+val* var_ /* var : Collection[Object] */;
+val* var5 /* : Iterator[nullable Object] */;
+val* var_6 /* var : Iterator[Object] */;
+short int var7 /* : Bool */;
+val* var8 /* : nullable Object */;
+val* var_p /* var p: Object */;
+val* var9 /* : HashMap[Object, Int] */;
+val* var11 /* : HashMap[Object, Int] */;
+val* var12 /* : nullable Object */;
+long var13 /* : Int */;
+long var_m /* var m: Int */;
+short int var14 /* : Bool */;
+short int var16 /* : Bool */;
+int cltype17;
+int idtype18;
+const char* var_class_name19;
+short int var20 /* : Bool */;
+val* var21 /* : HashMap[Object, Int] */;
+val* var23 /* : HashMap[Object, Int] */;
+val* var24 /* : nullable Object */;
+/* Covariant cast for argument 0 (h) <p0:Object> isa H */
+/* <p0:Object> isa H */
+type_struct = self->type->resolution_table->types[COLOR_nit__POSetGroupColorer___35dH];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
+var1 = 0;
+} else {
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
+}
+if (unlikely(!var1)) {
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "H", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 397);
+fatal_exit(1);
+}
+var_h = p0;
+var_res = 0l;
+{
+var2 = nit___nit__POSetGroupColorer___poset(self);
+}
+{
+var3 = poset___poset__POSet____91d_93d(var2, var_h);
+}
+{
+var4 = poset___poset__POSetElement___direct_greaters(var3);
+}
+var_ = var4;
+{
+var5 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[Object]>*/
+}
+var_6 = var5;
+for(;;) {
+{
+var7 = ((short int(*)(val* self))((((long)var_6&3)?class_info[((long)var_6&3)]:var_6->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_6); /* is_ok on <var_6:Iterator[Object]>*/
+}
+if (var7){
+{
+var8 = ((val*(*)(val* self))((((long)var_6&3)?class_info[((long)var_6&3)]:var_6->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_6); /* item on <var_6:Iterator[Object]>*/
+}
+var_p = var8;
+{
+{ /* Inline coloring#POSetGroupColorer#min_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var11 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___min_colors].val; /* _min_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var11 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _min_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 409);
+fatal_exit(1);
+}
+var9 = var11;
+RET_LABEL10:(void)0;
+}
+}
+{
+var12 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var9, var_p);
+}
+var13 = (long)(var12)>>2;
+var_m = var13;
+{
+{ /* Inline kernel#Int#> (var_m,var_res) on <var_m:Int> */
+/* Covariant cast for argument 0 (i) <var_res:Int> isa OTHER */
+/* <var_res:Int> isa OTHER */
+var16 = 1; /* easy <var_res:Int> isa OTHER*/
+if (unlikely(!var16)) {
+var_class_name19 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name19);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 536);
+fatal_exit(1);
+}
+var20 = var_m > var_res;
+var14 = var20;
+goto RET_LABEL15;
+RET_LABEL15:(void)0;
+}
+}
+if (var14){
+var_res = var_m;
+} else {
+}
+{
+((void(*)(val* self))((((long)var_6&3)?class_info[((long)var_6&3)]:var_6->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_6); /* next on <var_6:Iterator[Object]>*/
+}
+} else {
+goto BREAK_label;
+}
+}
+BREAK_label: (void)0;
+{
+((void(*)(val* self))((((long)var_6&3)?class_info[((long)var_6&3)]:var_6->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_6); /* finish on <var_6:Iterator[Object]>*/
+}
+{
+{ /* Inline coloring#POSetGroupColorer#min_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var23 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___min_colors].val; /* _min_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var23 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _min_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 409);
+fatal_exit(1);
+}
+var21 = var23;
+RET_LABEL22:(void)0;
+}
+}
+{
+var24 = (val*)(var_res<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var21, var_h, var24); /* Direct call hash_collection#HashMap#[]= on <var21:HashMap[Object, Int]>*/
+}
+var = var_res;
+goto RET_LABEL;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#min_colors for (self: POSetGroupColorer[Object, Object]): HashMap[Object, Int] */
+val* nit___nit__POSetGroupColorer___min_colors(val* self) {
+val* var /* : HashMap[Object, Int] */;
+val* var1 /* : HashMap[Object, Int] */;
+var1 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___min_colors].val; /* _min_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _min_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 409);
+fatal_exit(1);
+}
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#next_free_color for (self: POSetGroupColorer[Object, Object], Int, Collection[Object]): Int */
+long nit___nit__POSetGroupColorer___next_free_color(val* self, long p0, val* p1) {
+long var /* : Int */;
+short int var1 /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+long var_color /* var color: Int */;
+val* var_set /* var set: Collection[Object] */;
+val* var_ /* var : Collection[Object] */;
+val* var2 /* : Iterator[nullable Object] */;
+val* var_3 /* var : Iterator[Object] */;
+short int var4 /* : Bool */;
+val* var5 /* : nullable Object */;
+val* var_h /* var h: Object */;
+val* var6 /* : HashMap[Object, HashSet[Int]] */;
+val* var8 /* : HashMap[Object, HashSet[Int]] */;
+val* var9 /* : nullable Object */;
+short int var10 /* : Bool */;
+val* var11 /* : nullable Object */;
+long var12 /* : Int */;
+short int var14 /* : Bool */;
+int cltype15;
+int idtype16;
+const char* var_class_name17;
+long var18 /* : Int */;
+/* Covariant cast for argument 1 (set) <p1:Collection[Object]> isa Collection[H] */
+/* <p1:Collection[Object]> isa Collection[H] */
+type_struct = self->type->resolution_table->types[COLOR_standard__Collection__nit__POSetGroupColorer___35dH];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->table_size) {
+var1 = 0;
+} else {
+var1 = (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->type_table[cltype] == idtype;
+}
+if (unlikely(!var1)) {
+var_class_name = p1 == NULL ? "null" : (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[H]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 416);
+fatal_exit(1);
+}
+var_color = p0;
+var_set = p1;
+for(;;) {
+var_ = var_set;
+{
+var2 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[Object]>*/
+}
+var_3 = var2;
+for(;;) {
+{
+var4 = ((short int(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_3); /* is_ok on <var_3:Iterator[Object]>*/
+}
+if (var4){
+{
+var5 = ((val*(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_3); /* item on <var_3:Iterator[Object]>*/
+}
+var_h = var5;
+{
+{ /* Inline coloring#POSetGroupColorer#used_colors (self) on <self:POSetGroupColorer[Object, Object]> */
+var8 = self->attrs[COLOR_nit__coloring__POSetGroupColorer___used_colors].val; /* _used_colors on <self:POSetGroupColorer[Object, Object]> */
+if (unlikely(var8 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _used_colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 314);
+fatal_exit(1);
+}
+var6 = var8;
+RET_LABEL7:(void)0;
+}
+}
+{
+var9 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var6, var_h);
+}
+{
+var11 = (val*)(var_color<<2|1);
+var10 = standard___standard__HashSet___standard__abstract_collection__Collection__has(var9, var11);
+}
+if (var10){
+{
+{ /* Inline kernel#Int#+ (var_color,1l) on <var_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var14 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var14)) {
+var_class_name17 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name17);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var18 = var_color + 1l;
+var12 = var18;
+goto RET_LABEL13;
+RET_LABEL13:(void)0;
+}
+}
+var_color = var12;
+goto BREAK_;
+} else {
+}
+{
+((void(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_3); /* next on <var_3:Iterator[Object]>*/
+}
+} else {
+goto BREAK_label;
+}
+}
+BREAK_label: (void)0;
+{
+((void(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_3); /* finish on <var_3:Iterator[Object]>*/
+}
+goto BREAK_19;
+BREAK_: (void)0;
+}
+BREAK_19: (void)0;
+var = var_color;
+goto RET_LABEL;
+RET_LABEL:;
+return var;
+}
+/* method coloring#POSetGroupColorer#init for (self: POSetGroupColorer[Object, Object]) */
+void nit___nit__POSetGroupColorer___standard__kernel__Object__init(val* self) {
+{
+((void(*)(val* self))(self->class->vft[COLOR_nit___nit__POSetGroupColorer___standard__kernel__Object__init]))(self); /* init on <self:POSetGroupColorer[Object, Object]>*/
+}
+RET_LABEL:;
+}
+/* method coloring#BucketsColorer#colors for (self: BucketsColorer[Object, Object]): HashMap[Object, Int] */
+val* nit___nit__BucketsColorer___colors(val* self) {
+val* var /* : HashMap[Object, Int] */;
+val* var1 /* : HashMap[Object, Int] */;
+var1 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 453);
+fatal_exit(1);
+}
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method coloring#BucketsColorer#conflicts for (self: BucketsColorer[Object, Object]): HashMap[Object, Set[Object]] */
+val* nit___nit__BucketsColorer___conflicts(val* self) {
+val* var /* : HashMap[Object, Set[Object]] */;
+val* var1 /* : HashMap[Object, Set[Object]] */;
+var1 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
+if (unlikely(var1 == NULL)) {
+PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
+}
+var = var1;
+RET_LABEL:;
+return var;
+}
+/* method coloring#BucketsColorer#colorize for (self: BucketsColorer[Object, Object], Map[Object, Set[Object]]): Map[Object, Int] */
+val* nit___nit__BucketsColorer___colorize(val* self, val* p0) {
+val* var /* : Map[Object, Int] */;
+short int var1 /* : Bool */;
+int cltype;
+int idtype;
+const struct type* type_struct;
+const char* var_class_name;
+val* var_buckets /* var buckets: Map[Object, Set[Object]] */;
+long var_min_color /* var min_color: Int */;
+val* var_ /* var : Map[Object, Set[Object]] */;
+val* var2 /* : MapIterator[nullable Object, nullable Object] */;
+val* var_3 /* var : MapIterator[Object, Set[Object]] */;
+short int var4 /* : Bool */;
+val* var5 /* : nullable Object */;
+val* var_holder /* var holder: Object */;
+val* var6 /* : nullable Object */;
+val* var_hbuckets /* var hbuckets: Set[Object] */;
+val* var_7 /* var : Set[Object] */;
+val* var8 /* : Iterator[nullable Object] */;
+val* var_9 /* var : Iterator[Object] */;
+short int var10 /* : Bool */;
+val* var11 /* : nullable Object */;
+val* var_bucket /* var bucket: Object */;
+val* var12 /* : HashMap[Object, Int] */;
+val* var14 /* : HashMap[Object, Int] */;
+short int var15 /* : Bool */;
+long var_color /* var color: Int */;
+short int var16 /* : Bool */;
+short int var17 /* : Bool */;
+long var18 /* : Int */;
+short int var20 /* : Bool */;
+int cltype21;
+int idtype22;
+const char* var_class_name23;
+long var24 /* : Int */;
+val* var26 /* : HashMap[Object, Int] */;
+val* var28 /* : HashMap[Object, Int] */;
+val* var29 /* : nullable Object */;
+val* var33 /* : HashMap[Object, Int] */;
+val* var35 /* : HashMap[Object, Int] */;
+/* Covariant cast for argument 0 (buckets) <p0:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
+/* <p0:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
+type_struct = self->type->resolution_table->types[COLOR_standard__Map__nit__BucketsColorer___35dH__standard__Set__nit__BucketsColorer___35dE];
+cltype = type_struct->color;
+idtype = type_struct->id;
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
+var1 = 0;
+} else {
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
+}
+if (unlikely(!var1)) {
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Set[E]]", var_class_name);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 456);
+fatal_exit(1);
+}
+var_buckets = p0;
+{
+nit___nit__BucketsColorer___compute_conflicts(self, var_buckets); /* Direct call coloring#BucketsColorer#compute_conflicts on <self:BucketsColorer[Object, Object]>*/
+}
+var_min_color = 0l;
+var_ = var_buckets;
+{
+var2 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__MapRead__iterator]))(var_); /* iterator on <var_:Map[Object, Set[Object]]>*/
+}
+var_3 = var2;
+for(;;) {
+{
+var4 = ((short int(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__MapIterator__is_ok]))(var_3); /* is_ok on <var_3:MapIterator[Object, Set[Object]]>*/
+}
+if (var4){
 {
-var6 = ((val* (*)(val* self))(var_4->class->vft[COLOR_standard__abstract_collection__MapIterator__key]))(var_4) /* key on <var_4:MapIterator[Object, Set[Object]]>*/;
+var5 = ((val*(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__MapIterator__key]))(var_3); /* key on <var_3:MapIterator[Object, Set[Object]]>*/
 }
-var_holder = var6;
+var_holder = var5;
 {
-var7 = ((val* (*)(val* self))(var_4->class->vft[COLOR_standard__abstract_collection__MapIterator__item]))(var_4) /* item on <var_4:MapIterator[Object, Set[Object]]>*/;
+var6 = ((val*(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__MapIterator__item]))(var_3); /* item on <var_3:MapIterator[Object, Set[Object]]>*/
 }
-var_hbuckets = var7;
-var_8 = var_hbuckets;
+var_hbuckets = var6;
+var_7 = var_hbuckets;
 {
-var9 = ((val* (*)(val* self))(var_8->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_8) /* iterator on <var_8:Set[Object]>*/;
+var8 = ((val*(*)(val* self))((((long)var_7&3)?class_info[((long)var_7&3)]:var_7->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_7); /* iterator on <var_7:Set[Object]>*/
 }
-var_10 = var9;
+var_9 = var8;
 for(;;) {
 {
-var11 = ((short int (*)(val* self))(var_10->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_10) /* is_ok on <var_10:Iterator[Object]>*/;
+var10 = ((short int(*)(val* self))((((long)var_9&3)?class_info[((long)var_9&3)]:var_9->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_9); /* is_ok on <var_9:Iterator[Object]>*/
 }
-if (var11){
+if (var10){
 {
-var12 = ((val* (*)(val* self))(var_10->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_10) /* item on <var_10:Iterator[Object]>*/;
+var11 = ((val*(*)(val* self))((((long)var_9&3)?class_info[((long)var_9&3)]:var_9->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_9); /* item on <var_9:Iterator[Object]>*/
 }
-var_bucket = var12;
+var_bucket = var11;
 {
 { /* Inline coloring#BucketsColorer#colors (self) on <self:BucketsColorer[Object, Object]> */
-var15 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
-if (unlikely(var15 == NULL)) {
+var14 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
+if (unlikely(var14 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 284);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 453);
+fatal_exit(1);
 }
-var13 = var15;
-RET_LABEL14:(void)0;
+var12 = var14;
+RET_LABEL13:(void)0;
 }
 }
 {
-var16 = standard___standard__MapRead___has_key(var13, var_bucket);
+var15 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var12, var_bucket);
 }
-if (var16){
+if (var15){
 goto BREAK_label;
 } else {
 }
 var_color = var_min_color;
 for(;;) {
 {
-var17 = nit___nit__BucketsColorer___is_color_free(self, var_bucket, var_color);
+var16 = nit___nit__BucketsColorer___is_color_free(self, var_bucket, var_color);
 }
-var18 = !var17;
-if (var18){
-var19 = 1;
-{
-{ /* Inline kernel#Int#+ (var_color,var19) on <var_color: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_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name25);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 413);
-show_backtrace(1);
-}
-var26 = var_color + var19;
-var20 = var26;
-goto RET_LABEL21;
-RET_LABEL21:(void)0;
+var17 = !var16;
+if (var17){
+{
+{ /* Inline kernel#Int#+ (var_color,1l) on <var_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var20 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var20)) {
+var_class_name23 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name23);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var24 = var_color + 1l;
+var18 = var24;
+goto RET_LABEL19;
+RET_LABEL19:(void)0;
 }
 }
-var_color = var20;
+var_color = var18;
 } else {
-goto BREAK_label27;
+goto BREAK_label25;
 }
 }
-BREAK_label27: (void)0;
+BREAK_label25: (void)0;
 {
 { /* Inline coloring#BucketsColorer#colors (self) on <self:BucketsColorer[Object, Object]> */
-var30 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
-if (unlikely(var30 == NULL)) {
+var28 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
+if (unlikely(var28 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 284);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 453);
+fatal_exit(1);
 }
-var28 = var30;
-RET_LABEL29:(void)0;
+var26 = var28;
+RET_LABEL27:(void)0;
 }
 }
 {
-var31 = BOX_standard__Int(var_color); /* autobox from Int to nullable Object */
-standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var28, var_bucket, var31); /* Direct call hash_collection#HashMap#[]= on <var28:HashMap[Object, Int]>*/
+var29 = (val*)(var_color<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var26, var_bucket, var29); /* Direct call hash_collection#HashMap#[]= on <var26:HashMap[Object, Int]>*/
 }
 var_color = var_min_color;
 BREAK_label: (void)0;
 {
-((void (*)(val* self))(var_10->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_10) /* next on <var_10:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_9&3)?class_info[((long)var_9&3)]:var_9->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_9); /* next on <var_9:Iterator[Object]>*/
 }
 } else {
-goto BREAK_label32;
+goto BREAK_label30;
 }
 }
-BREAK_label32: (void)0;
+BREAK_label30: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_10) on <var_10:Iterator[Object]> */
-RET_LABEL33:(void)0;
-}
+((void(*)(val* self))((((long)var_9&3)?class_info[((long)var_9&3)]:var_9->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_9); /* finish on <var_9:Iterator[Object]>*/
 }
 {
-((void (*)(val* self))(var_4->class->vft[COLOR_standard__abstract_collection__MapIterator__next]))(var_4) /* next on <var_4:MapIterator[Object, Set[Object]]>*/;
+((void(*)(val* self))((((long)var_3&3)?class_info[((long)var_3&3)]:var_3->class)->vft[COLOR_standard__abstract_collection__MapIterator__next]))(var_3); /* next on <var_3:MapIterator[Object, Set[Object]]>*/
 }
 } else {
-goto BREAK_label34;
+goto BREAK_label31;
 }
 }
-BREAK_label34: (void)0;
+BREAK_label31: (void)0;
 {
-{ /* Inline abstract_collection#MapIterator#finish (var_4) on <var_4:MapIterator[Object, Set[Object]]> */
-RET_LABEL35:(void)0;
+{ /* Inline abstract_collection#MapIterator#finish (var_3) on <var_3:MapIterator[Object, Set[Object]]> */
+RET_LABEL32:(void)0;
 }
 }
 {
 { /* Inline coloring#BucketsColorer#colors (self) on <self:BucketsColorer[Object, Object]> */
-var38 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
-if (unlikely(var38 == NULL)) {
+var35 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
+if (unlikely(var35 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 284);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 453);
+fatal_exit(1);
 }
-var36 = var38;
-RET_LABEL37:(void)0;
+var33 = var35;
+RET_LABEL34:(void)0;
 }
 }
-var = var36;
+var = var33;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2584,23 +4352,21 @@ val* var23 /* : nullable Object */;
 short int var24 /* : Bool */;
 short int var26 /* : Bool */;
 long var27 /* : Int */;
-short int var28 /* : Bool */;
-short int var30 /* : Bool */;
 /* Covariant cast for argument 0 (bucket) <p0:Object> isa E */
 /* <p0:Object> isa E */
 type_struct = self->type->resolution_table->types[COLOR_nit__BucketsColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var1)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "E", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 305);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 474);
+fatal_exit(1);
 }
 var_bucket = p0;
 var_color = p1;
@@ -2609,15 +4375,15 @@ var_color = p1;
 var4 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var4 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var2 = var4;
 RET_LABEL3:(void)0;
 }
 }
 {
-var5 = standard___standard__MapRead___has_key(var2, var_bucket);
+var5 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var2, var_bucket);
 }
 if (var5){
 {
@@ -2625,8 +4391,8 @@ if (var5){
 var8 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var8 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var6 = var8;
 RET_LABEL7:(void)0;
@@ -2637,16 +4403,16 @@ var9 = standard___standard__HashMap___standard__abstract_collection__MapRead___9
 }
 var_ = var9;
 {
-var10 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Set[Object]>*/;
+var10 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Set[Object]>*/
 }
 var_11 = var10;
 for(;;) {
 {
-var12 = ((short int (*)(val* self))(var_11->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_11) /* is_ok on <var_11:Iterator[Object]>*/;
+var12 = ((short int(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_11); /* is_ok on <var_11:Iterator[Object]>*/
 }
 if (var12){
 {
-var13 = ((val* (*)(val* self))(var_11->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_11) /* item on <var_11:Iterator[Object]>*/;
+var13 = ((val*(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_11); /* item on <var_11:Iterator[Object]>*/
 }
 var_other = var13;
 {
@@ -2654,15 +4420,15 @@ var_other = var13;
 var17 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var17 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 284);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 453);
+fatal_exit(1);
 }
 var15 = var17;
 RET_LABEL16:(void)0;
 }
 }
 {
-var18 = standard___standard__MapRead___has_key(var15, var_other);
+var18 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var15, var_other);
 }
 var_19 = var18;
 if (var18){
@@ -2671,8 +4437,8 @@ if (var18){
 var22 = self->attrs[COLOR_nit__coloring__BucketsColorer___colors].val; /* _colors on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var22 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 284);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 453);
+fatal_exit(1);
 }
 var20 = var22;
 RET_LABEL21:(void)0;
@@ -2683,11 +4449,8 @@ var23 = standard___standard__HashMap___standard__abstract_collection__MapRead___
 }
 {
 { /* Inline kernel#Int#== (var23,var_color) on <var23:nullable Object(Int)> */
-var26 = (var23 != NULL) && (var23->class == &class_standard__Int);
-if (var26) {
-var27 = ((struct instance_standard__Int*)var23)->value; /* autounbox from nullable Object to Int */;
-var26 = (var27 == var_color);
-}
+var27 = (long)(var23)>>2;
+var26 = (var23 != NULL) && (var27 == var_color);
 var24 = var26;
 goto RET_LABEL25;
 RET_LABEL25:(void)0;
@@ -2698,13 +4461,12 @@ var14 = var24;
 var14 = var_19;
 }
 if (var14){
-var28 = 0;
-var = var28;
+var = 0;
 goto RET_LABEL;
 } else {
 }
 {
-((void (*)(val* self))(var_11->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_11) /* next on <var_11:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_11); /* next on <var_11:Iterator[Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -2712,14 +4474,11 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_11) on <var_11:Iterator[Object]> */
-RET_LABEL29:(void)0;
-}
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_11); /* finish on <var_11:Iterator[Object]>*/
 }
 } else {
 }
-var30 = 1;
-var = var30;
+var = 1;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -2780,16 +4539,16 @@ val* var45 /* : nullable Object */;
 type_struct = self->type->resolution_table->types[COLOR_standard__Map__nit__BucketsColorer___35dH__standard__Set__nit__BucketsColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var = 0;
 } else {
-var = p0->type->type_table[cltype] == idtype;
+var = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Set[E]]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 314);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 483);
+fatal_exit(1);
 }
 var_buckets = p0;
 {
@@ -2797,8 +4556,8 @@ var_buckets = p0;
 var3 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var3 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var1 = var3;
 RET_LABEL2:(void)0;
@@ -2809,34 +4568,34 @@ standard___standard__HashMap___standard__abstract_collection__Map__clear(var1);
 }
 var_ = var_buckets;
 {
-var4 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__MapRead__iterator]))(var_) /* iterator on <var_:Map[Object, Set[Object]]>*/;
+var4 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__MapRead__iterator]))(var_); /* iterator on <var_:Map[Object, Set[Object]]>*/
 }
 var_5 = var4;
 for(;;) {
 {
-var6 = ((short int (*)(val* self))(var_5->class->vft[COLOR_standard__abstract_collection__MapIterator__is_ok]))(var_5) /* is_ok on <var_5:MapIterator[Object, Set[Object]]>*/;
+var6 = ((short int(*)(val* self))((((long)var_5&3)?class_info[((long)var_5&3)]:var_5->class)->vft[COLOR_standard__abstract_collection__MapIterator__is_ok]))(var_5); /* is_ok on <var_5:MapIterator[Object, Set[Object]]>*/
 }
 if (var6){
 {
-var7 = ((val* (*)(val* self))(var_5->class->vft[COLOR_standard__abstract_collection__MapIterator__key]))(var_5) /* key on <var_5:MapIterator[Object, Set[Object]]>*/;
+var7 = ((val*(*)(val* self))((((long)var_5&3)?class_info[((long)var_5&3)]:var_5->class)->vft[COLOR_standard__abstract_collection__MapIterator__key]))(var_5); /* key on <var_5:MapIterator[Object, Set[Object]]>*/
 }
 var_holder = var7;
 {
-var8 = ((val* (*)(val* self))(var_5->class->vft[COLOR_standard__abstract_collection__MapIterator__item]))(var_5) /* item on <var_5:MapIterator[Object, Set[Object]]>*/;
+var8 = ((val*(*)(val* self))((((long)var_5&3)?class_info[((long)var_5&3)]:var_5->class)->vft[COLOR_standard__abstract_collection__MapIterator__item]))(var_5); /* item on <var_5:MapIterator[Object, Set[Object]]>*/
 }
 var_hbuckets = var8;
 var_9 = var_hbuckets;
 {
-var10 = ((val* (*)(val* self))(var_9->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_9) /* iterator on <var_9:Set[Object]>*/;
+var10 = ((val*(*)(val* self))((((long)var_9&3)?class_info[((long)var_9&3)]:var_9->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_9); /* iterator on <var_9:Set[Object]>*/
 }
 var_11 = var10;
 for(;;) {
 {
-var12 = ((short int (*)(val* self))(var_11->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_11) /* is_ok on <var_11:Iterator[Object]>*/;
+var12 = ((short int(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_11); /* is_ok on <var_11:Iterator[Object]>*/
 }
 if (var12){
 {
-var13 = ((val* (*)(val* self))(var_11->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_11) /* item on <var_11:Iterator[Object]>*/;
+var13 = ((val*(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_11); /* item on <var_11:Iterator[Object]>*/
 }
 var_bucket = var13;
 {
@@ -2844,15 +4603,15 @@ var_bucket = var13;
 var16 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var16 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var14 = var16;
 RET_LABEL15:(void)0;
 }
 }
 {
-var17 = standard___standard__MapRead___has_key(var14, var_bucket);
+var17 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var14, var_bucket);
 }
 var18 = !var17;
 if (var18){
@@ -2861,8 +4620,8 @@ if (var18){
 var21 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var21 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var19 = var21;
 RET_LABEL20:(void)0;
@@ -2879,20 +4638,20 @@ standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(
 }
 var_23 = var_hbuckets;
 {
-var24 = ((val* (*)(val* self))(var_23->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_23) /* iterator on <var_23:Set[Object]>*/;
+var24 = ((val*(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_23); /* iterator on <var_23:Set[Object]>*/
 }
 var_25 = var24;
 for(;;) {
 {
-var26 = ((short int (*)(val* self))(var_25->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_25) /* is_ok on <var_25:Iterator[Object]>*/;
+var26 = ((short int(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_25); /* is_ok on <var_25:Iterator[Object]>*/
 }
 if (var26){
 {
-var27 = ((val* (*)(val* self))(var_25->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_25) /* item on <var_25:Iterator[Object]>*/;
+var27 = ((val*(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_25); /* item on <var_25:Iterator[Object]>*/
 }
 var_obucket = var27;
 {
-var28 = ((short int (*)(val* self, val* p0))(var_obucket->class->vft[COLOR_standard__kernel__Object___61d_61d]))(var_obucket, var_bucket) /* == on <var_obucket:Object>*/;
+var28 = ((short int(*)(val* self, val* p0))((((long)var_obucket&3)?class_info[((long)var_obucket&3)]:var_obucket->class)->vft[COLOR_standard__kernel__Object___61d_61d]))(var_obucket, var_bucket); /* == on <var_obucket:Object>*/
 }
 if (var28){
 goto BREAK_label;
@@ -2903,15 +4662,15 @@ goto BREAK_label;
 var31 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var31 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var29 = var31;
 RET_LABEL30:(void)0;
 }
 }
 {
-var32 = standard___standard__MapRead___has_key(var29, var_obucket);
+var32 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var29, var_obucket);
 }
 var33 = !var32;
 if (var33){
@@ -2920,8 +4679,8 @@ if (var33){
 var36 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var36 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var34 = var36;
 RET_LABEL35:(void)0;
@@ -2941,8 +4700,8 @@ standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(
 var40 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var40 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var38 = var40;
 RET_LABEL39:(void)0;
@@ -2952,15 +4711,15 @@ RET_LABEL39:(void)0;
 var41 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var38, var_bucket);
 }
 {
-((void (*)(val* self, val* p0))(var41->class->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var41, var_obucket) /* add on <var41:nullable Object(Set[Object])>*/;
+((void(*)(val* self, val* p0))((((long)var41&3)?class_info[((long)var41&3)]:var41->class)->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var41, var_obucket); /* add on <var41:nullable Object(Set[Object])>*/
 }
 {
 { /* Inline coloring#BucketsColorer#conflicts (self) on <self:BucketsColorer[Object, Object]> */
 var44 = self->attrs[COLOR_nit__coloring__BucketsColorer___conflicts].val; /* _conflicts on <self:BucketsColorer[Object, Object]> */
 if (unlikely(var44 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 285);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 454);
+fatal_exit(1);
 }
 var42 = var44;
 RET_LABEL43:(void)0;
@@ -2970,11 +4729,11 @@ RET_LABEL43:(void)0;
 var45 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var42, var_obucket);
 }
 {
-((void (*)(val* self, val* p0))(var45->class->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var45, var_bucket) /* add on <var45:nullable Object(Set[Object])>*/;
+((void(*)(val* self, val* p0))((((long)var45&3)?class_info[((long)var45&3)]:var45->class)->vft[COLOR_standard__abstract_collection__SimpleCollection__add]))(var45, var_bucket); /* add on <var45:nullable Object(Set[Object])>*/
 }
 BREAK_label: (void)0;
 {
-((void (*)(val* self))(var_25->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_25) /* next on <var_25:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_25); /* next on <var_25:Iterator[Object]>*/
 }
 } else {
 goto BREAK_label46;
@@ -2982,34 +4741,30 @@ goto BREAK_label46;
 }
 BREAK_label46: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_25) on <var_25:Iterator[Object]> */
-RET_LABEL47:(void)0;
-}
+((void(*)(val* self))((((long)var_25&3)?class_info[((long)var_25&3)]:var_25->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_25); /* finish on <var_25:Iterator[Object]>*/
 }
 {
-((void (*)(val* self))(var_11->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_11) /* next on <var_11:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_11); /* next on <var_11:Iterator[Object]>*/
 }
 } else {
-goto BREAK_label48;
+goto BREAK_label47;
 }
 }
-BREAK_label48: (void)0;
+BREAK_label47: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_11) on <var_11:Iterator[Object]> */
-RET_LABEL49:(void)0;
-}
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_11); /* finish on <var_11:Iterator[Object]>*/
 }
 {
-((void (*)(val* self))(var_5->class->vft[COLOR_standard__abstract_collection__MapIterator__next]))(var_5) /* next on <var_5:MapIterator[Object, Set[Object]]>*/;
+((void(*)(val* self))((((long)var_5&3)?class_info[((long)var_5&3)]:var_5->class)->vft[COLOR_standard__abstract_collection__MapIterator__next]))(var_5); /* next on <var_5:MapIterator[Object, Set[Object]]>*/
 }
 } else {
-goto BREAK_label50;
+goto BREAK_label48;
 }
 }
-BREAK_label50: (void)0;
+BREAK_label48: (void)0;
 {
 { /* Inline abstract_collection#MapIterator#finish (var_5) on <var_5:MapIterator[Object, Set[Object]]> */
-RET_LABEL51:(void)0;
+RET_LABEL49:(void)0;
 }
 }
 RET_LABEL:;
@@ -3021,8 +4776,8 @@ val* var1 /* : HashMap[Object, Int] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -3035,8 +4790,8 @@ val* var1 /* : POSet[Object] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___poset].val; /* _poset on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 336);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 505);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -3062,8 +4817,8 @@ 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`", "POSet[H]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 336);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 505);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetBucketsColorer___poset].val = p0; /* _poset on <self:POSetBucketsColorer[Object, Object]> */
 RET_LABEL:;
@@ -3075,8 +4830,8 @@ val* var1 /* : Map[Object, Set[Object]] */;
 var1 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___conflicts].val; /* _conflicts on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var1 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 337);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 506);
+fatal_exit(1);
 }
 var = var1;
 RET_LABEL:;
@@ -3094,16 +4849,16 @@ const char* var_class_name;
 type_struct = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetBucketsColorer___35dH__standard__Set__nit__POSetBucketsColorer___35dH];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var = 0;
 } else {
-var = p0->type->type_table[cltype] == idtype;
+var = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Set[H]]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 337);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 506);
+fatal_exit(1);
 }
 self->attrs[COLOR_nit__coloring__POSetBucketsColorer___conflicts].val = p0; /* _conflicts on <self:POSetBucketsColorer[Object, Object]> */
 RET_LABEL:;
@@ -3148,39 +4903,37 @@ short int var29 /* : Bool */;
 short int var30 /* : Bool */;
 short int var31 /* : Bool */;
 long var32 /* : Int */;
-long var33 /* : Int */;
-short int var35 /* : Bool */;
-int cltype36;
-int idtype37;
-const char* var_class_name38;
-long var39 /* : Int */;
-val* var41 /* : HashMap[Object, Int] */;
-val* var43 /* : HashMap[Object, Int] */;
-val* var44 /* : nullable Object */;
-long var45 /* : Int */;
-long var46 /* : Int */;
-short int var48 /* : Bool */;
-int cltype49;
-int idtype50;
-const char* var_class_name51;
-long var52 /* : Int */;
-val* var57 /* : HashMap[Object, Int] */;
-val* var59 /* : HashMap[Object, Int] */;
+short int var34 /* : Bool */;
+int cltype35;
+int idtype36;
+const char* var_class_name37;
+long var38 /* : Int */;
+val* var40 /* : HashMap[Object, Int] */;
+val* var42 /* : HashMap[Object, Int] */;
+val* var43 /* : nullable Object */;
+long var44 /* : Int */;
+short int var46 /* : Bool */;
+int cltype47;
+int idtype48;
+const char* var_class_name49;
+long var50 /* : Int */;
+val* var53 /* : HashMap[Object, Int] */;
+val* var55 /* : HashMap[Object, Int] */;
 /* Covariant cast for argument 0 (buckets) <p0:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 /* <p0:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 type_struct = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetBucketsColorer___35dH__standard__Set__nit__POSetBucketsColorer___35dE];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var1)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Set[E]]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 339);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 508);
+fatal_exit(1);
 }
 var_buckets = p0;
 {
@@ -3188,8 +4941,8 @@ var_buckets = p0;
 var4 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var4 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
 var2 = var4;
 RET_LABEL3:(void)0;
@@ -3203,15 +4956,15 @@ standard___standard__HashMap___standard__abstract_collection__Map__clear(var2);
 var7 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___poset].val; /* _poset on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var7 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 336);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 505);
+fatal_exit(1);
 }
 var5 = var7;
 RET_LABEL6:(void)0;
 }
 }
 {
-var8 = ((val* (*)(val* self))(var_buckets->class->vft[COLOR_standard__abstract_collection__MapRead__keys]))(var_buckets) /* keys on <var_buckets:Map[Object, Set[Object]]>*/;
+var8 = ((val*(*)(val* self))((((long)var_buckets&3)?class_info[((long)var_buckets&3)]:var_buckets->class)->vft[COLOR_standard__abstract_collection__MapRead__keys]))(var_buckets); /* keys on <var_buckets:Map[Object, Set[Object]]>*/
 }
 {
 var9 = poset___poset__POSet___linearize(var5, var8);
@@ -3235,8 +4988,8 @@ var_h = var13;
 var16 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___poset].val; /* _poset on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var16 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _poset");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 336);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 505);
+fatal_exit(1);
 }
 var14 = var16;
 RET_LABEL15:(void)0;
@@ -3253,20 +5006,20 @@ var19 = nit___nit__POSetBucketsColorer___min_color(self, var18, var_buckets);
 }
 var_color = var19;
 {
-var20 = ((val* (*)(val* self, val* p0))(var_buckets->class->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var_buckets, var_h) /* [] on <var_buckets:Map[Object, Set[Object]]>*/;
+var20 = ((val*(*)(val* self, val* p0))((((long)var_buckets&3)?class_info[((long)var_buckets&3)]:var_buckets->class)->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var_buckets, var_h); /* [] on <var_buckets:Map[Object, Set[Object]]>*/
 }
 var_21 = var20;
 {
-var22 = ((val* (*)(val* self))(var_21->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_21) /* iterator on <var_21:Set[Object]>*/;
+var22 = ((val*(*)(val* self))((((long)var_21&3)?class_info[((long)var_21&3)]:var_21->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_21); /* iterator on <var_21:Set[Object]>*/
 }
 var_23 = var22;
 for(;;) {
 {
-var24 = ((short int (*)(val* self))(var_23->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_23) /* is_ok on <var_23:Iterator[Object]>*/;
+var24 = ((short int(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_23); /* is_ok on <var_23:Iterator[Object]>*/
 }
 if (var24){
 {
-var25 = ((val* (*)(val* self))(var_23->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_23) /* item on <var_23:Iterator[Object]>*/;
+var25 = ((val*(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_23); /* item on <var_23:Iterator[Object]>*/
 }
 var_bucket = var25;
 {
@@ -3274,15 +5027,15 @@ var_bucket = var25;
 var28 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var28 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
 var26 = var28;
 RET_LABEL27:(void)0;
 }
 }
 {
-var29 = standard___standard__MapRead___has_key(var26, var_bucket);
+var29 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var26, var_bucket);
 }
 if (var29){
 goto BREAK_label;
@@ -3294,105 +5047,99 @@ var30 = nit___nit__POSetBucketsColorer___is_color_free(self, var_color, var_h, v
 }
 var31 = !var30;
 if (var31){
-var32 = 1;
-{
-{ /* Inline kernel#Int#+ (var_color,var32) on <var_color:Int> */
-/* Covariant cast for argument 0 (i) <var32:Int> isa OTHER */
-/* <var32:Int> isa OTHER */
-var35 = 1; /* easy <var32:Int> isa OTHER*/
-if (unlikely(!var35)) {
-var_class_name38 = type_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name38);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 413);
-show_backtrace(1);
-}
-var39 = var_color + var32;
-var33 = var39;
-goto RET_LABEL34;
-RET_LABEL34:(void)0;
+{
+{ /* Inline kernel#Int#+ (var_color,1l) on <var_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var34 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var34)) {
+var_class_name37 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name37);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var38 = var_color + 1l;
+var32 = var38;
+goto RET_LABEL33;
+RET_LABEL33:(void)0;
 }
 }
-var_color = var33;
+var_color = var32;
 } else {
-goto BREAK_label40;
+goto BREAK_label39;
 }
 }
-BREAK_label40: (void)0;
+BREAK_label39: (void)0;
 {
 { /* Inline coloring#POSetBucketsColorer#colors (self) on <self:POSetBucketsColorer[Object, Object]> */
-var43 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
-if (unlikely(var43 == NULL)) {
+var42 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
+if (unlikely(var42 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
-var41 = var43;
-RET_LABEL42:(void)0;
+var40 = var42;
+RET_LABEL41:(void)0;
 }
 }
 {
-var44 = BOX_standard__Int(var_color); /* autobox from Int to nullable Object */
-standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var41, var_bucket, var44); /* Direct call hash_collection#HashMap#[]= on <var41:HashMap[Object, Int]>*/
+var43 = (val*)(var_color<<2|1);
+standard___standard__HashMap___standard__abstract_collection__Map___91d_93d_61d(var40, var_bucket, var43); /* Direct call hash_collection#HashMap#[]= on <var40:HashMap[Object, Int]>*/
 }
-var45 = 1;
 {
-{ /* Inline kernel#Int#+ (var_color,var45) on <var_color:Int> */
-/* Covariant cast for argument 0 (i) <var45:Int> isa OTHER */
-/* <var45:Int> isa OTHER */
-var48 = 1; /* easy <var45:Int> isa OTHER*/
-if (unlikely(!var48)) {
-var_class_name51 = type_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name51);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 413);
-show_backtrace(1);
-}
-var52 = var_color + var45;
-var46 = var52;
-goto RET_LABEL47;
-RET_LABEL47:(void)0;
+{ /* Inline kernel#Int#+ (var_color,1l) on <var_color:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var46 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var46)) {
+var_class_name49 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name49);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
+}
+var50 = var_color + 1l;
+var44 = var50;
+goto RET_LABEL45;
+RET_LABEL45:(void)0;
 }
 }
-var_color = var46;
+var_color = var44;
 BREAK_label: (void)0;
 {
-((void (*)(val* self))(var_23->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_23) /* next on <var_23:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_23); /* next on <var_23:Iterator[Object]>*/
 }
 } else {
-goto BREAK_label53;
+goto BREAK_label51;
 }
 }
-BREAK_label53: (void)0;
+BREAK_label51: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_23) on <var_23:Iterator[Object]> */
-RET_LABEL54:(void)0;
-}
+((void(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_23); /* finish on <var_23:Iterator[Object]>*/
 }
 {
 standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__next(var_11); /* Direct call array#ArrayIterator#next on <var_11:ArrayIterator[Object]>*/
 }
 } else {
-goto BREAK_label55;
+goto BREAK_label52;
 }
 }
-BREAK_label55: (void)0;
+BREAK_label52: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_11) on <var_11:ArrayIterator[Object]> */
-RET_LABEL56:(void)0;
-}
+standard__array___standard__array__ArrayIterator___standard__abstract_collection__Iterator__finish(var_11); /* Direct call array#ArrayIterator#finish on <var_11:ArrayIterator[Object]>*/
 }
 {
 { /* Inline coloring#POSetBucketsColorer#colors (self) on <self:POSetBucketsColorer[Object, Object]> */
-var59 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
-if (unlikely(var59 == NULL)) {
+var55 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
+if (unlikely(var55 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
-var57 = var59;
-RET_LABEL58:(void)0;
+var53 = var55;
+RET_LABEL54:(void)0;
 }
 }
-var = var57;
+var = var53;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -3413,115 +5160,112 @@ const char* var_class_name6;
 val* var_others /* var others: Collection[Object] */;
 val* var_buckets /* var buckets: Map[Object, Set[Object]] */;
 long var7 /* : Int */;
-long var8 /* : Int */;
-long var10 /* : Int */;
+long var9 /* : Int */;
 long var_min /* var min: Int */;
 val* var_ /* var : Collection[Object] */;
-val* var11 /* : Iterator[nullable Object] */;
-val* var_12 /* var : Iterator[Object] */;
-short int var13 /* : Bool */;
-val* var14 /* : nullable Object */;
+val* var10 /* : Iterator[nullable Object] */;
+val* var_11 /* var : Iterator[Object] */;
+short int var12 /* : Bool */;
+val* var13 /* : nullable Object */;
 val* var_holder /* var holder: Object */;
-long var15 /* : Int */;
+long var14 /* : Int */;
 long var_color /* var color: Int */;
-short int var16 /* : Bool */;
-short int var18 /* : Bool */;
-int cltype19;
-int idtype20;
-const char* var_class_name21;
-short int var22 /* : Bool */;
-long var24 /* : Int */;
-long var25 /* : Int */;
-short int var27 /* : Bool */;
-int cltype28;
-int idtype29;
-const char* var_class_name30;
-long var31 /* : Int */;
+short int var15 /* : Bool */;
+short int var17 /* : Bool */;
+int cltype18;
+int idtype19;
+const char* var_class_name20;
+short int var21 /* : Bool */;
+long var22 /* : Int */;
+short int var24 /* : Bool */;
+int cltype25;
+int idtype26;
+const char* var_class_name27;
+long var28 /* : Int */;
 /* Covariant cast for argument 0 (others) <p0:Collection[Object]> isa Collection[H] */
 /* <p0:Collection[Object]> isa Collection[H] */
 type_struct = self->type->resolution_table->types[COLOR_standard__Collection__nit__POSetBucketsColorer___35dH];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var1)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Collection[H]", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 354);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 523);
+fatal_exit(1);
 }
 /* Covariant cast for argument 1 (buckets) <p1:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 /* <p1:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 type_struct5 = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetBucketsColorer___35dH__standard__Set__nit__POSetBucketsColorer___35dE];
 cltype3 = type_struct5->color;
 idtype4 = type_struct5->id;
-if(cltype3 >= p1->type->table_size) {
+if(cltype3 >= (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->table_size) {
 var2 = 0;
 } else {
-var2 = p1->type->type_table[cltype3] == idtype4;
+var2 = (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->type_table[cltype3] == idtype4;
 }
 if (unlikely(!var2)) {
-var_class_name6 = p1 == NULL ? "null" : p1->type->name;
+var_class_name6 = p1 == NULL ? "null" : (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Set[E]]", var_class_name6);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 354);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 523);
+fatal_exit(1);
 }
 var_others = p0;
 var_buckets = p1;
-var7 = 1;
 {
-{ /* Inline kernel#Int#unary - (var7) on <var7:Int> */
-var10 = -var7;
-var8 = var10;
-goto RET_LABEL9;
-RET_LABEL9:(void)0;
+{ /* Inline kernel#Int#unary - (1l) on <1l:Int> */
+var9 = -1l;
+var7 = var9;
+goto RET_LABEL8;
+RET_LABEL8:(void)0;
 }
 }
-var_min = var8;
+var_min = var7;
 var_ = var_others;
 {
-var11 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Collection[Object]>*/;
+var10 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Collection[Object]>*/
 }
-var_12 = var11;
+var_11 = var10;
 for(;;) {
 {
-var13 = ((short int (*)(val* self))(var_12->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_12) /* is_ok on <var_12:Iterator[Object]>*/;
+var12 = ((short int(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_11); /* is_ok on <var_11:Iterator[Object]>*/
 }
-if (var13){
+if (var12){
 {
-var14 = ((val* (*)(val* self))(var_12->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_12) /* item on <var_12:Iterator[Object]>*/;
+var13 = ((val*(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_11); /* item on <var_11:Iterator[Object]>*/
 }
-var_holder = var14;
+var_holder = var13;
 {
-var15 = nit___nit__POSetBucketsColorer___max_color(self, var_holder, var_buckets);
+var14 = nit___nit__POSetBucketsColorer___max_color(self, var_holder, var_buckets);
 }
-var_color = var15;
+var_color = var14;
 {
 { /* Inline kernel#Int#> (var_color,var_min) on <var_color:Int> */
 /* Covariant cast for argument 0 (i) <var_min:Int> isa OTHER */
 /* <var_min:Int> isa OTHER */
-var18 = 1; /* easy <var_min:Int> isa OTHER*/
-if (unlikely(!var18)) {
-var_class_name21 = type_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name21);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 412);
-show_backtrace(1);
-}
-var22 = var_color > var_min;
-var16 = var22;
-goto RET_LABEL17;
-RET_LABEL17:(void)0;
+var17 = 1; /* easy <var_min:Int> isa OTHER*/
+if (unlikely(!var17)) {
+var_class_name20 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name20);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 536);
+fatal_exit(1);
+}
+var21 = var_color > var_min;
+var15 = var21;
+goto RET_LABEL16;
+RET_LABEL16:(void)0;
 }
 }
-if (var16){
+if (var15){
 var_min = var_color;
 } else {
 }
 {
-((void (*)(val* self))(var_12->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_12) /* next on <var_12:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_11); /* next on <var_11:Iterator[Object]>*/
 }
 } else {
 goto BREAK_label;
@@ -3529,29 +5273,26 @@ goto BREAK_label;
 }
 BREAK_label: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_12) on <var_12:Iterator[Object]> */
-RET_LABEL23:(void)0;
+((void(*)(val* self))((((long)var_11&3)?class_info[((long)var_11&3)]:var_11->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_11); /* finish on <var_11:Iterator[Object]>*/
 }
-}
-var24 = 1;
 {
-{ /* Inline kernel#Int#+ (var_min,var24) on <var_min: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_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name30);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 413);
-show_backtrace(1);
+{ /* Inline kernel#Int#+ (var_min,1l) on <var_min:Int> */
+/* Covariant cast for argument 0 (i) <1l:Int> isa OTHER */
+/* <1l:Int> isa OTHER */
+var24 = 1; /* easy <1l:Int> isa OTHER*/
+if (unlikely(!var24)) {
+var_class_name27 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name27);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 537);
+fatal_exit(1);
 }
-var31 = var_min + var24;
-var25 = var31;
-goto RET_LABEL26;
-RET_LABEL26:(void)0;
+var28 = var_min + 1l;
+var22 = var28;
+goto RET_LABEL23;
+RET_LABEL23:(void)0;
 }
 }
-var = var25;
+var = var22;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -3572,163 +5313,159 @@ const char* var_class_name6;
 val* var_holder /* var holder: Object */;
 val* var_buckets /* var buckets: Map[Object, Set[Object]] */;
 long var7 /* : Int */;
-long var8 /* : Int */;
-long var10 /* : Int */;
+long var9 /* : Int */;
 long var_max /* var max: Int */;
-val* var11 /* : nullable Object */;
+val* var10 /* : nullable Object */;
 val* var_ /* var : Set[Object] */;
-val* var12 /* : Iterator[nullable Object] */;
-val* var_13 /* var : Iterator[Object] */;
-short int var14 /* : Bool */;
-val* var15 /* : nullable Object */;
+val* var11 /* : Iterator[nullable Object] */;
+val* var_12 /* var : Iterator[Object] */;
+short int var13 /* : Bool */;
+val* var14 /* : nullable Object */;
 val* var_bucket /* var bucket: Object */;
-val* var16 /* : HashMap[Object, Int] */;
-val* var18 /* : HashMap[Object, Int] */;
+val* var15 /* : HashMap[Object, Int] */;
+val* var17 /* : HashMap[Object, Int] */;
+short int var18 /* : Bool */;
 short int var19 /* : Bool */;
-short int var20 /* : Bool */;
-val* var21 /* : HashMap[Object, Int] */;
-val* var23 /* : HashMap[Object, Int] */;
-val* var24 /* : nullable Object */;
-long var25 /* : Int */;
+val* var20 /* : HashMap[Object, Int] */;
+val* var22 /* : HashMap[Object, Int] */;
+val* var23 /* : nullable Object */;
+long var24 /* : Int */;
 long var_color /* var color: Int */;
-short int var26 /* : Bool */;
-short int var28 /* : Bool */;
-int cltype29;
-int idtype30;
-const char* var_class_name31;
-short int var32 /* : Bool */;
+short int var25 /* : Bool */;
+short int var27 /* : Bool */;
+int cltype28;
+int idtype29;
+const char* var_class_name30;
+short int var31 /* : Bool */;
 /* Covariant cast for argument 0 (holder) <p0:Object> isa H */
 /* <p0:Object> isa H */
 type_struct = self->type->resolution_table->types[COLOR_nit__POSetBucketsColorer___35dH];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p0->type->table_size) {
+if(cltype >= (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p0->type->type_table[cltype] == idtype;
+var1 = (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var1)) {
-var_class_name = p0 == NULL ? "null" : p0->type->name;
+var_class_name = p0 == NULL ? "null" : (((long)p0&3)?type_info[((long)p0&3)]:p0->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "H", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 364);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 533);
+fatal_exit(1);
 }
 /* Covariant cast for argument 1 (buckets) <p1:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 /* <p1:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 type_struct5 = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetBucketsColorer___35dH__standard__Set__nit__POSetBucketsColorer___35dE];
 cltype3 = type_struct5->color;
 idtype4 = type_struct5->id;
-if(cltype3 >= p1->type->table_size) {
+if(cltype3 >= (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->table_size) {
 var2 = 0;
 } else {
-var2 = p1->type->type_table[cltype3] == idtype4;
+var2 = (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->type_table[cltype3] == idtype4;
 }
 if (unlikely(!var2)) {
-var_class_name6 = p1 == NULL ? "null" : p1->type->name;
+var_class_name6 = p1 == NULL ? "null" : (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Set[E]]", var_class_name6);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 364);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 533);
+fatal_exit(1);
 }
 var_holder = p0;
 var_buckets = p1;
-var7 = 1;
 {
-{ /* Inline kernel#Int#unary - (var7) on <var7:Int> */
-var10 = -var7;
-var8 = var10;
-goto RET_LABEL9;
-RET_LABEL9:(void)0;
+{ /* Inline kernel#Int#unary - (1l) on <1l:Int> */
+var9 = -1l;
+var7 = var9;
+goto RET_LABEL8;
+RET_LABEL8:(void)0;
 }
 }
-var_max = var8;
+var_max = var7;
 {
-var11 = ((val* (*)(val* self, val* p0))(var_buckets->class->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var_buckets, var_holder) /* [] on <var_buckets:Map[Object, Set[Object]]>*/;
+var10 = ((val*(*)(val* self, val* p0))((((long)var_buckets&3)?class_info[((long)var_buckets&3)]:var_buckets->class)->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var_buckets, var_holder); /* [] on <var_buckets:Map[Object, Set[Object]]>*/
 }
-var_ = var11;
+var_ = var10;
 {
-var12 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Set[Object]>*/;
+var11 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Set[Object]>*/
 }
-var_13 = var12;
+var_12 = var11;
 for(;;) {
 {
-var14 = ((short int (*)(val* self))(var_13->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_13) /* is_ok on <var_13:Iterator[Object]>*/;
+var13 = ((short int(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_12); /* is_ok on <var_12:Iterator[Object]>*/
 }
-if (var14){
+if (var13){
 {
-var15 = ((val* (*)(val* self))(var_13->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_13) /* item on <var_13:Iterator[Object]>*/;
+var14 = ((val*(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_12); /* item on <var_12:Iterator[Object]>*/
 }
-var_bucket = var15;
+var_bucket = var14;
 {
 { /* Inline coloring#POSetBucketsColorer#colors (self) on <self:POSetBucketsColorer[Object, Object]> */
-var18 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
-if (unlikely(var18 == NULL)) {
+var17 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
+if (unlikely(var17 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
-var16 = var18;
-RET_LABEL17:(void)0;
+var15 = var17;
+RET_LABEL16:(void)0;
 }
 }
 {
-var19 = standard___standard__MapRead___has_key(var16, var_bucket);
+var18 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var15, var_bucket);
 }
-var20 = !var19;
-if (var20){
+var19 = !var18;
+if (var19){
 goto BREAK_label;
 } else {
 }
 {
 { /* Inline coloring#POSetBucketsColorer#colors (self) on <self:POSetBucketsColorer[Object, Object]> */
-var23 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
-if (unlikely(var23 == NULL)) {
+var22 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
+if (unlikely(var22 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
-var21 = var23;
-RET_LABEL22:(void)0;
+var20 = var22;
+RET_LABEL21:(void)0;
 }
 }
 {
-var24 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var21, var_bucket);
+var23 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var20, var_bucket);
 }
-var25 = ((struct instance_standard__Int*)var24)->value; /* autounbox from nullable Object to Int */;
-var_color = var25;
+var24 = (long)(var23)>>2;
+var_color = var24;
 {
 { /* Inline kernel#Int#> (var_color,var_max) on <var_color:Int> */
 /* Covariant cast for argument 0 (i) <var_max:Int> isa OTHER */
 /* <var_max:Int> isa OTHER */
-var28 = 1; /* easy <var_max:Int> isa OTHER*/
-if (unlikely(!var28)) {
-var_class_name31 = type_standard__Int.name;
-PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name31);
-PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 412);
-show_backtrace(1);
-}
-var32 = var_color > var_max;
-var26 = var32;
-goto RET_LABEL27;
-RET_LABEL27:(void)0;
+var27 = 1; /* easy <var_max:Int> isa OTHER*/
+if (unlikely(!var27)) {
+var_class_name30 = type_standard__Int.name;
+PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "OTHER", var_class_name30);
+PRINT_ERROR(" (%s:%d)\n", FILE_standard__kernel, 536);
+fatal_exit(1);
 }
+var31 = var_color > var_max;
+var25 = var31;
+goto RET_LABEL26;
+RET_LABEL26:(void)0;
 }
-if (var26){
+}
+if (var25){
 var_max = var_color;
 } else {
 }
 BREAK_label: (void)0;
 {
-((void (*)(val* self))(var_13->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_13) /* next on <var_13:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_12); /* next on <var_12:Iterator[Object]>*/
 }
 } else {
-goto BREAK_label33;
+goto BREAK_label32;
 }
 }
-BREAK_label33: (void)0;
+BREAK_label32: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_13) on <var_13:Iterator[Object]> */
-RET_LABEL34:(void)0;
-}
+((void(*)(val* self))((((long)var_12&3)?class_info[((long)var_12&3)]:var_12->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_12); /* finish on <var_12:Iterator[Object]>*/
 }
 var = var_max;
 goto RET_LABEL;
@@ -3755,66 +5492,63 @@ val* var7 /* : Map[Object, Set[Object]] */;
 val* var9 /* : Map[Object, Set[Object]] */;
 short int var10 /* : Bool */;
 short int var11 /* : Bool */;
-short int var12 /* : Bool */;
-val* var13 /* : Map[Object, Set[Object]] */;
-val* var15 /* : Map[Object, Set[Object]] */;
-val* var16 /* : nullable Object */;
+val* var12 /* : Map[Object, Set[Object]] */;
+val* var14 /* : Map[Object, Set[Object]] */;
+val* var15 /* : nullable Object */;
 val* var_ /* var : Set[Object] */;
-val* var17 /* : Iterator[nullable Object] */;
-val* var_18 /* var : Iterator[Object] */;
-short int var19 /* : Bool */;
-val* var20 /* : nullable Object */;
+val* var16 /* : Iterator[nullable Object] */;
+val* var_17 /* var : Iterator[Object] */;
+short int var18 /* : Bool */;
+val* var19 /* : nullable Object */;
 val* var_conflict /* var conflict: Object */;
-val* var21 /* : nullable Object */;
-val* var_22 /* var : Set[Object] */;
-val* var23 /* : Iterator[nullable Object] */;
-val* var_24 /* var : Iterator[Object] */;
-short int var25 /* : Bool */;
-val* var26 /* : nullable Object */;
+val* var20 /* : nullable Object */;
+val* var_21 /* var : Set[Object] */;
+val* var22 /* : Iterator[nullable Object] */;
+val* var_23 /* var : Iterator[Object] */;
+short int var24 /* : Bool */;
+val* var25 /* : nullable Object */;
 val* var_bucket /* var bucket: Object */;
-val* var27 /* : HashMap[Object, Int] */;
-val* var29 /* : HashMap[Object, Int] */;
+val* var26 /* : HashMap[Object, Int] */;
+val* var28 /* : HashMap[Object, Int] */;
+short int var29 /* : Bool */;
 short int var30 /* : Bool */;
-short int var31 /* : Bool */;
-val* var32 /* : HashMap[Object, Int] */;
-val* var34 /* : HashMap[Object, Int] */;
-val* var35 /* : nullable Object */;
-short int var36 /* : Bool */;
-short int var38 /* : Bool */;
-long var39 /* : Int */;
-short int var40 /* : Bool */;
-short int var45 /* : Bool */;
+val* var31 /* : HashMap[Object, Int] */;
+val* var33 /* : HashMap[Object, Int] */;
+val* var34 /* : nullable Object */;
+short int var35 /* : Bool */;
+short int var37 /* : Bool */;
+long var38 /* : Int */;
 /* Covariant cast for argument 1 (holder) <p1:Object> isa H */
 /* <p1:Object> isa H */
 type_struct = self->type->resolution_table->types[COLOR_nit__POSetBucketsColorer___35dH];
 cltype = type_struct->color;
 idtype = type_struct->id;
-if(cltype >= p1->type->table_size) {
+if(cltype >= (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->table_size) {
 var1 = 0;
 } else {
-var1 = p1->type->type_table[cltype] == idtype;
+var1 = (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->type_table[cltype] == idtype;
 }
 if (unlikely(!var1)) {
-var_class_name = p1 == NULL ? "null" : p1->type->name;
+var_class_name = p1 == NULL ? "null" : (((long)p1&3)?type_info[((long)p1&3)]:p1->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "H", var_class_name);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 375);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 544);
+fatal_exit(1);
 }
 /* Covariant cast for argument 2 (buckets) <p2:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 /* <p2:Map[Object, Set[Object]]> isa Map[H, Set[E]] */
 type_struct5 = self->type->resolution_table->types[COLOR_standard__Map__nit__POSetBucketsColorer___35dH__standard__Set__nit__POSetBucketsColorer___35dE];
 cltype3 = type_struct5->color;
 idtype4 = type_struct5->id;
-if(cltype3 >= p2->type->table_size) {
+if(cltype3 >= (((long)p2&3)?type_info[((long)p2&3)]:p2->type)->table_size) {
 var2 = 0;
 } else {
-var2 = p2->type->type_table[cltype3] == idtype4;
+var2 = (((long)p2&3)?type_info[((long)p2&3)]:p2->type)->type_table[cltype3] == idtype4;
 }
 if (unlikely(!var2)) {
-var_class_name6 = p2 == NULL ? "null" : p2->type->name;
+var_class_name6 = p2 == NULL ? "null" : (((long)p2&3)?type_info[((long)p2&3)]:p2->type)->name;
 PRINT_ERROR("Runtime error: Cast failed. Expected `%s`, got `%s`", "Map[H, Set[E]]", var_class_name6);
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 375);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 544);
+fatal_exit(1);
 }
 var_color = p0;
 var_holder = p1;
@@ -3824,151 +5558,141 @@ var_buckets = p2;
 var9 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___conflicts].val; /* _conflicts on <self:POSetBucketsColorer[Object, Object]> */
 if (unlikely(var9 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 337);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 506);
+fatal_exit(1);
 }
 var7 = var9;
 RET_LABEL8:(void)0;
 }
 }
 {
-var10 = standard___standard__MapRead___has_key(var7, var_holder);
+var10 = ((short int(*)(val* self, val* p0))((((long)var7&3)?class_info[((long)var7&3)]:var7->class)->vft[COLOR_standard__abstract_collection__MapRead__has_key]))(var7, var_holder); /* has_key on <var7:Map[Object, Set[Object]]>*/
 }
 var11 = !var10;
 if (var11){
-var12 = 1;
-var = var12;
+var = 1;
 goto RET_LABEL;
 } else {
 }
 {
 { /* Inline coloring#POSetBucketsColorer#conflicts (self) on <self:POSetBucketsColorer[Object, Object]> */
-var15 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___conflicts].val; /* _conflicts on <self:POSetBucketsColorer[Object, Object]> */
-if (unlikely(var15 == NULL)) {
+var14 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___conflicts].val; /* _conflicts on <self:POSetBucketsColorer[Object, Object]> */
+if (unlikely(var14 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _conflicts");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 337);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 506);
+fatal_exit(1);
 }
-var13 = var15;
-RET_LABEL14:(void)0;
+var12 = var14;
+RET_LABEL13:(void)0;
 }
 }
 {
-var16 = ((val* (*)(val* self, val* p0))(var13->class->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var13, var_holder) /* [] on <var13:Map[Object, Set[Object]]>*/;
+var15 = ((val*(*)(val* self, val* p0))((((long)var12&3)?class_info[((long)var12&3)]:var12->class)->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var12, var_holder); /* [] on <var12:Map[Object, Set[Object]]>*/
 }
-var_ = var16;
+var_ = var15;
 {
-var17 = ((val* (*)(val* self))(var_->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_) /* iterator on <var_:Set[Object]>*/;
+var16 = ((val*(*)(val* self))((((long)var_&3)?class_info[((long)var_&3)]:var_->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_); /* iterator on <var_:Set[Object]>*/
 }
-var_18 = var17;
+var_17 = var16;
 for(;;) {
 {
-var19 = ((short int (*)(val* self))(var_18->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_18) /* is_ok on <var_18:Iterator[Object]>*/;
+var18 = ((short int(*)(val* self))((((long)var_17&3)?class_info[((long)var_17&3)]:var_17->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_17); /* is_ok on <var_17:Iterator[Object]>*/
 }
-if (var19){
+if (var18){
 {
-var20 = ((val* (*)(val* self))(var_18->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_18) /* item on <var_18:Iterator[Object]>*/;
+var19 = ((val*(*)(val* self))((((long)var_17&3)?class_info[((long)var_17&3)]:var_17->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_17); /* item on <var_17:Iterator[Object]>*/
 }
-var_conflict = var20;
+var_conflict = var19;
 {
-var21 = ((val* (*)(val* self, val* p0))(var_buckets->class->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var_buckets, var_conflict) /* [] on <var_buckets:Map[Object, Set[Object]]>*/;
+var20 = ((val*(*)(val* self, val* p0))((((long)var_buckets&3)?class_info[((long)var_buckets&3)]:var_buckets->class)->vft[COLOR_standard__abstract_collection__MapRead___91d_93d]))(var_buckets, var_conflict); /* [] on <var_buckets:Map[Object, Set[Object]]>*/
 }
-var_22 = var21;
+var_21 = var20;
 {
-var23 = ((val* (*)(val* self))(var_22->class->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_22) /* iterator on <var_22:Set[Object]>*/;
+var22 = ((val*(*)(val* self))((((long)var_21&3)?class_info[((long)var_21&3)]:var_21->class)->vft[COLOR_standard__abstract_collection__Collection__iterator]))(var_21); /* iterator on <var_21:Set[Object]>*/
 }
-var_24 = var23;
+var_23 = var22;
 for(;;) {
 {
-var25 = ((short int (*)(val* self))(var_24->class->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_24) /* is_ok on <var_24:Iterator[Object]>*/;
+var24 = ((short int(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__is_ok]))(var_23); /* is_ok on <var_23:Iterator[Object]>*/
 }
-if (var25){
+if (var24){
 {
-var26 = ((val* (*)(val* self))(var_24->class->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_24) /* item on <var_24:Iterator[Object]>*/;
+var25 = ((val*(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__item]))(var_23); /* item on <var_23:Iterator[Object]>*/
 }
-var_bucket = var26;
+var_bucket = var25;
 {
 { /* Inline coloring#POSetBucketsColorer#colors (self) on <self:POSetBucketsColorer[Object, Object]> */
-var29 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
-if (unlikely(var29 == NULL)) {
+var28 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
+if (unlikely(var28 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
-var27 = var29;
-RET_LABEL28:(void)0;
+var26 = var28;
+RET_LABEL27:(void)0;
 }
 }
 {
-var30 = standard___standard__MapRead___has_key(var27, var_bucket);
+var29 = standard___standard__HashMap___standard__abstract_collection__MapRead__has_key(var26, var_bucket);
 }
-var31 = !var30;
-if (var31){
+var30 = !var29;
+if (var30){
 goto BREAK_label;
 } else {
 }
 {
 { /* Inline coloring#POSetBucketsColorer#colors (self) on <self:POSetBucketsColorer[Object, Object]> */
-var34 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
-if (unlikely(var34 == NULL)) {
+var33 = self->attrs[COLOR_nit__coloring__POSetBucketsColorer___colors].val; /* _colors on <self:POSetBucketsColorer[Object, Object]> */
+if (unlikely(var33 == NULL)) {
 PRINT_ERROR("Runtime error: %s", "Uninitialized attribute _colors");
-PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 335);
-show_backtrace(1);
+PRINT_ERROR(" (%s:%d)\n", FILE_nit__coloring, 504);
+fatal_exit(1);
 }
-var32 = var34;
-RET_LABEL33:(void)0;
+var31 = var33;
+RET_LABEL32:(void)0;
 }
 }
 {
-var35 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var32, var_bucket);
+var34 = standard___standard__HashMap___standard__abstract_collection__MapRead___91d_93d(var31, var_bucket);
 }
 {
-{ /* Inline kernel#Int#== (var35,var_color) on <var35:nullable Object(Int)> */
-var38 = (var35 != NULL) && (var35->class == &class_standard__Int);
-if (var38) {
-var39 = ((struct instance_standard__Int*)var35)->value; /* autounbox from nullable Object to Int */;
-var38 = (var39 == var_color);
-}
-var36 = var38;
-goto RET_LABEL37;
-RET_LABEL37:(void)0;
+{ /* Inline kernel#Int#== (var34,var_color) on <var34:nullable Object(Int)> */
+var38 = (long)(var34)>>2;
+var37 = (var34 != NULL) && (var38 == var_color);
+var35 = var37;
+goto RET_LABEL36;
+RET_LABEL36:(void)0;
 }
 }
-if (var36){
-var40 = 0;
-var = var40;
+if (var35){
+var = 0;
 goto RET_LABEL;
 } else {
 }
 BREAK_label: (void)0;
 {
-((void (*)(val* self))(var_24->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_24) /* next on <var_24:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_23); /* next on <var_23:Iterator[Object]>*/
 }
 } else {
-goto BREAK_label41;
+goto BREAK_label39;
 }
 }
-BREAK_label41: (void)0;
+BREAK_label39: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_24) on <var_24:Iterator[Object]> */
-RET_LABEL42:(void)0;
-}
+((void(*)(val* self))((((long)var_23&3)?class_info[((long)var_23&3)]:var_23->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_23); /* finish on <var_23:Iterator[Object]>*/
 }
 {
-((void (*)(val* self))(var_18->class->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_18) /* next on <var_18:Iterator[Object]>*/;
+((void(*)(val* self))((((long)var_17&3)?class_info[((long)var_17&3)]:var_17->class)->vft[COLOR_standard__abstract_collection__Iterator__next]))(var_17); /* next on <var_17:Iterator[Object]>*/
 }
 } else {
-goto BREAK_label43;
+goto BREAK_label40;
 }
 }
-BREAK_label43: (void)0;
+BREAK_label40: (void)0;
 {
-{ /* Inline abstract_collection#Iterator#finish (var_18) on <var_18:Iterator[Object]> */
-RET_LABEL44:(void)0;
-}
+((void(*)(val* self))((((long)var_17&3)?class_info[((long)var_17&3)]:var_17->class)->vft[COLOR_standard__abstract_collection__Iterator__finish]))(var_17); /* finish on <var_17:Iterator[Object]>*/
 }
-var45 = 1;
-var = var45;
+var = 1;
 goto RET_LABEL;
 RET_LABEL:;
 return var;
@@ -3976,7 +5700,7 @@ return var;
 /* method coloring#POSetBucketsColorer#init for (self: POSetBucketsColorer[Object, Object]) */
 void nit___nit__POSetBucketsColorer___standard__kernel__Object__init(val* self) {
 {
-((void (*)(val* self))(self->class->vft[COLOR_nit___nit__POSetBucketsColorer___standard__kernel__Object__init]))(self) /* init on <self:POSetBucketsColorer[Object, Object]>*/;
+((void(*)(val* self))(self->class->vft[COLOR_nit___nit__POSetBucketsColorer___standard__kernel__Object__init]))(self); /* init on <self:POSetBucketsColorer[Object, Object]>*/
 }
 RET_LABEL:;
 }