[turbofan] Correctly handle illegal redeclarations.

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index 742797c9fe7085e7a5ad5d1a02fb933494df40b5..6809cfed01cee4a23734fe64c26e113683d81d12 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -514,6 +514,13 @@ void AstGraphBuilder::CreateGraphBody(bool stack_check) {
     NewNode(javascript()->CallRuntime(Runtime::kTraceEnter, 0));
   }
 
+  // Visit illegal re-declaration and bail out if it exists.
+  if (scope->HasIllegalRedeclaration()) {
+    AstEffectContext for_effect(this);
+    scope->VisitIllegalRedeclaration(this);
+    return;
+  }
+
   // Visit implicit declaration of the function name.
   if (scope->is_function_scope() && scope->function() != NULL) {
     VisitVariableDeclaration(scope->function());