[destructuring] Implement initializers in patterns.

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index da2a98fcf310462264a0ace0fb5432e95fdcef6e..f65405897ccc51365bb93cf4b9f9237b86410612 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -1004,12 +1004,17 @@ class Parser : public ParserBase<ParserTraits> {
       current_value_ = old_value;
     }
 
+    Variable* CreateTemp(Expression* value);
+
     AstNodeFactory* factory() const { return descriptor_->parser->factory(); }
     AstValueFactory* ast_value_factory() const {
       return descriptor_->parser->ast_value_factory();
     }
     bool inside_with() const { return descriptor_->parser->inside_with(); }
     Zone* zone() const { return descriptor_->parser->zone(); }
+    Scope* TemporaryDeclarationScope() const {

[rossberg, 2015/05/18 16:17:19]

Nit: is there a strong reason to say "Temporary" here?

[Dmitry Lomov (no reviews), 2015/05/18 17:31:22]

Yes, it is a declaration scope for temporary variables (as opposed to
declaration scope for the variables pattern matcher declares, which is
controlled by DeclarationDescriptor and ultimately by whether this is a lexical
declaration or not). However I inlined into CreateTempVar.

+      return descriptor_->parser->scope_->DeclarationScope();
+    }
 
     Expression* pattern_;
     int initializer_position_;