Reject uses of lexical for-loop variable on the RHS.

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index a626d99fa0a078cbaffb97deb3fb448e4d6c8dd2..061abb2b634f360423199c0aa634423cec463115 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -2839,17 +2839,20 @@ Statement* Parser::ParseForStatement(ZoneStringList* labels, bool* ok) {
         Variable* temp = top_scope_->DeclarationScope()->NewTemporary(name);
         VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
         Interface* interface = Interface::NewValue();

[Michael Starzinger, 2012/10/05 08:42:36]

Can we also move the interface down right before the loop variable is created?

[rossberg, 2012/10/05 09:15:02]

Inlined instead.

-        VariableProxy* each =
-            top_scope_->NewUnresolved(factory(), name, interface);
         ForInStatement* loop = factory()->NewForInStatement(labels);
         Target target(&this->target_stack_, loop);
 
+        // The expression does not see the loop variable.
         Expect(Token::IN, CHECK_OK);
+        top_scope_ = saved_scope;
         Expression* enumerable = ParseExpression(true, CHECK_OK);
+        top_scope_ = for_scope;
         Expect(Token::RPAREN, CHECK_OK);
 
         Statement* body = ParseStatement(NULL, CHECK_OK);
         Block* body_block = factory()->NewBlock(NULL, 3, false);
+        VariableProxy* each =
+            top_scope_->NewUnresolved(factory(), name, interface);
         Assignment* assignment = factory()->NewAssignment(
             Token::ASSIGN, each, temp_proxy, RelocInfo::kNoPosition);
         Statement* assignment_statement =