Fixes

src/codegen/irgen.cpp

@@ -827,7 +827,7 @@ static void emitBBs(IRGenState* irstate, const char* bb_type, GuardList& out_gua
             if (full_blocks.count(b2) == 0 && partial_blocks.count(b2) == 0)
                 continue;
 
-            // printf("%d %d %ld %ld\n", b->idx, b2->idx, phi_ending_symbol_tables[b2]->size(), phis->size());
+            // printf("(%d %ld) -> (%d %ld)\n", b2->idx, phi_ending_symbol_tables[b2]->size(), b->idx, phis->size());
             compareKeyset(phi_ending_symbol_tables[b2], phis);
             assert(phi_ending_symbol_tables[b2]->size() == phis->size());
         }

src/codegen/irgen/irgenerator.cpp

@@ -2204,6 +2204,8 @@ private:
         SourceInfo* source = irstate->getSourceInfo();
         ScopeInfo* scope_info = irstate->getScopeInfo();
 
+        // Additional names to remove; remove them after iteration is done to new mess up the iterators
+        std::vector<std::string> also_remove;
         for (SymbolTable::iterator it = symbol_table.begin(); it != symbol_table.end();) {
             if (allowableFakeEndingSymbol(it->first)) {
                 ++it;
@@ -2216,6 +2218,8 @@ private:
             if (!source->liveness->isLiveAtEnd(it->first, myblock)) {
                 // printf("%s dead at end of %d; grabbed = %d, %d vrefs\n", it->first.c_str(), myblock->idx,
                 // it->second->isGrabbed(), it->second->getVrefs());
+                also_remove.push_back(getIsDefinedName(it->first));
+
                 it->second->decvref(emitter);
                 it = symbol_table.erase(it);
             } else if (source->phis->isRequiredAfter(it->first, myblock)) {
@@ -2245,6 +2249,10 @@ private:
             }
         }
 
+        for (const auto& s : also_remove) {
+            symbol_table.erase(s);
+        }
+
         const PhiAnalysis::RequiredSet& all_phis = source->phis->getAllRequiredAfter(myblock);
         for (PhiAnalysis::RequiredSet::const_iterator it = all_phis.begin(), end = all_phis.end(); it != end; ++it) {
             // printf("phi will be required for %s\n", it->c_str());

src/core/cfg.cpp

@@ -2200,6 +2200,8 @@ public:
             node->body[i]->accept(this);
         }
 
+        popRegion(); // for the retrun
+
         AST_Call* exit_call = makeCall(makeName(exitname_buf, AST_TYPE::Load, node->lineno));
         exit_call->args.push_back(makeName("None", AST_TYPE::Load, node->lineno));
         exit_call->args.push_back(makeName("None", AST_TYPE::Load, node->lineno));
@@ -2242,7 +2244,6 @@ public:
             curblock = orig_ending_block;
         }
 
-        popRegion(); // for the retrun
         if (return_dest->predecessors.size() == 0) {
             delete return_dest;
         } else {