[Interpreter] Localize the CanonicalHandleScope to parsing and renumbering.

src/ast/ast-numbering.cc

Index: src/ast/ast-numbering.cc
diff --git a/src/ast/ast-numbering.cc b/src/ast/ast-numbering.cc
index d0101828d6897f99c91e069024460c4aae10ebf6..a6172ab9ea14dd2011515794e9493b98a9c02934 100644
--- a/src/ast/ast-numbering.cc
+++ b/src/ast/ast-numbering.cc
@@ -577,6 +577,12 @@ bool AstNumberingVisitor::Renumber(FunctionLiteral* node) {
     DisableOptimization(kGenerator);
   }
 
+  // Create a canonical handle scope if compiling ignition bytecode. This is
+  // required by the constant array builder to de-duplicate objects without
+  // dereferencing handles.
+  std::unique_ptr<CanonicalHandleScope> canonical;
+  if (FLAG_ignition) canonical.reset(new CanonicalHandleScope(isolate_));

[marja, 2016/09/12 07:26:41]

Why do we need to create the canonical handle scope here? What internalizes
below?

+
   VisitDeclarations(scope->declarations());
   VisitStatements(node->body());