Detect conflicting variable bindings in harmony mode.

src/scopes.cc

Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index ddde48a77c50eaccb92ef21376dfc510f1a5aeb0..80cbeb7d0b61a1df6cdb8bedd564721c281bdc64 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -383,11 +383,11 @@ Variable* Scope::DeclareFunctionVar(Handle<String> name) {
 }
 
 
-void Scope::DeclareParameter(Handle<String> name) {
+void Scope::DeclareParameter(Handle<String> name, Variable::Mode mode) {
   ASSERT(!already_resolved());
   ASSERT(is_function_scope());
   Variable* var =
-      variables_.Declare(this, name, Variable::VAR, true, Variable::NORMAL);
+      variables_.Declare(this, name, mode, true, Variable::NORMAL);
   params_.Add(var);
 }
 
@@ -467,6 +467,25 @@ void Scope::VisitIllegalRedeclaration(AstVisitor* visitor) {
 }
 
 
+Declaration* Scope::CheckConflictingVarDeclarations() {
+  int length = decls_.length();
+  for (int i = 0; i < length; i++) {
+    Declaration* decl = decls_[i];
+    if (decl->mode() != Variable::VAR) continue;
+    Handle<String> name = decl->proxy()->name();
+    for (Scope* scope = decl->scope();
+         scope->is_block_scope() || scope->is_catch_scope();
+         scope = scope->outer_scope_) {
+      Variable* other_var = scope->variables_.Lookup(name);

[Lasse Reichstein, 2011/09/01 07:34:04]

This should be able to skip the first scope, where it only finds the decl
variable itself?

[Steven, 2011/09/01 15:01:33]

When by first scope you mean the innermost scope where the declaration is
'physically' located, then no, that one should not be skipped. However, the code
as of now skips the outermost scope (function/eval/global). I will add it for
consistency, even though the parser already checks for that case.
On 2011/09/01 07:34:04, Lasse Reichstein wrote:

+      if (other_var != NULL && other_var->mode() == Variable::LET) {

[Lasse Reichstein, 2011/09/01 07:34:04]

Is it only LET declarations that can conflict, or any non-VAR?

[Steven, 2011/09/01 15:01:33]

Yes any non-VAR. Will fix it.
On 2011/09/01 07:34:04, Lasse Reichstein wrote:

+        return decl;
+      }
+    }
+  }
+  return NULL;
+}
+
+
 template<class Allocator>
 void Scope::CollectUsedVariables(List<Variable*, Allocator>* locals) {
   // Collect variables in this scope.