Fix scopes for body of sloppy-mode for-in/of loop

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 9113e8c7a4e3ba46b936b38d1f4627ff0c426cf4..108cca23d922e6a190a497d4d0058eb1353de82b 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -3794,17 +3794,25 @@ Statement* Parser::ParseForStatement(ZoneList<const AstRawString*>* labels,
 
         // Make a block around the statement in case a lexical binding
         // is introduced, e.g. by a FunctionDeclaration.
+        // This block must not be based on for_scope because if a lexical

[rossberg, 2015/10/13 10:52:04]

What does "be based on" mean?

[Dan Ehrenberg, 2015/10/13 14:58:40]

Clarified wording

+        // binding is introduced which overlaps with the for-in/of, the
+        // top level should actually point to the outer scope.
+        Scope* body_scope = NewScope(for_scope, BLOCK_SCOPE);
+        scope_ = body_scope;
         Block* block =
             factory()->NewBlock(NULL, 1, false, RelocInfo::kNoPosition);
         Statement* body = ParseSubStatement(NULL, CHECK_OK);
         block->statements()->Add(body, zone());
         InitializeForEachStatement(loop, expression, enumerable, block);
         scope_ = saved_scope;
+        body_scope->set_end_position(scanner()->location().end_pos);
+        body_scope = body_scope->FinalizeBlockScope();
+        if (body_scope != nullptr) {
+          block->set_scope(body_scope);
+        }
         for_scope->set_end_position(scanner()->location().end_pos);
         for_scope = for_scope->FinalizeBlockScope();
-        if (for_scope != nullptr) {
-          block->set_scope(for_scope);
-        }
+        DCHECK(for_scope == nullptr);
         // Parsed for-in loop.
         return loop;