Detect conflicting variable bindings in harmony mode.

src/scopes.h

Index: src/scopes.h
diff --git a/src/scopes.h b/src/scopes.h
index c2c41799b93fdb94590bff2eb7e01a8d7016d700..4af19d3938194fd492d0e2f73ff021816e52df52 100644
--- a/src/scopes.h
+++ b/src/scopes.h
@@ -130,7 +130,7 @@ class Scope: public ZoneObject {
   // Declare a parameter in this scope.  When there are duplicated
   // parameters the rightmost one 'wins'.  However, the implementation
   // expects all parameters to be declared and from left to right.
-  void DeclareParameter(Handle<String> name);
+  void DeclareParameter(Handle<String> name, Variable::Mode mode);
 
   // Declare a local variable in this scope. If the variable has been
   // declared before, the previously declared variable is returned.
@@ -182,6 +182,10 @@ class Scope: public ZoneObject {
   // Check if the scope has (at least) one illegal redeclaration.
   bool HasIllegalRedeclaration() const { return illegal_redecl_ != NULL; }
 
+  // For harmony block scoping mode: Check if the scope has conflicting var
+  // declarations, i.e. a var declaration that has been hoisted from a nested
+  // scope over a let binding of the same name.
+  Declaration* CheckConflictingVarDeclarations();
 
   // ---------------------------------------------------------------------------
   // Scope-specific info.