Remove CONST_LEGACY VariableMode

src/contexts.cc

Index: src/contexts.cc
diff --git a/src/contexts.cc b/src/contexts.cc
index b3cf255736d812c15b97c4f136935799d792b52c..a8c25e9bf39729ccabeaaacfef2d2248a596a47c 100644
--- a/src/contexts.cc
+++ b/src/contexts.cc
@@ -178,7 +178,7 @@ static Maybe<bool> UnscopableLookup(LookupIterator* it) {
 
 static PropertyAttributes GetAttributesForMode(VariableMode mode) {
   DCHECK(IsDeclaredVariableMode(mode));
-  return IsImmutableVariableMode(mode) ? READ_ONLY : NONE;
+  return mode == CONST ? READ_ONLY : NONE;
 }
 
 Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
@@ -307,10 +307,11 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
       }
 
       // Check the slot corresponding to the intermediate context holding
-      // only the function name variable.
-      if (follow_context_chain && context->IsFunctionContext()) {
-        VariableMode mode;
-        int function_index = scope_info->FunctionContextSlotIndex(*name, &mode);
+      // only the function name variable. It's conceptually (and spec-wise)
+      // in an outer scope of the function's declaration scope.
+      if (follow_context_chain && (flags & STOP_AT_DECLARATION_SCOPE) == 0 &&

[adamk, 2016/08/11 01:02:39]

This was wrong before (the function name is conceptually in an outer scope), but
didn't cause any problems due to the way this function is called.

Without this fix, the following becomes an error when it should not be:

(function foo() { eval("var foo") })()

+          context->IsFunctionContext()) {
+        int function_index = scope_info->FunctionContextSlotIndex(*name);
         if (function_index >= 0) {
           if (FLAG_trace_contexts) {
             PrintF("=> found intermediate function in context slot %d\n",
@@ -318,9 +319,8 @@ Handle<Object> Context::Lookup(Handle<String> name, ContextLookupFlags flags,
           }
           *index = function_index;
           *attributes = READ_ONLY;
-          DCHECK(mode == CONST_LEGACY || mode == CONST);
           *init_flag = kCreatedInitialized;
-          *variable_mode = mode;
+          *variable_mode = CONST;
           return context;
         }
       }