WIP [esnext] implement async iteration proposal

src/ast/prettyprinter.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/prettyprinter.h"
 
 #include <stdarg.h>
 
 #include "src/ast/ast-value-factory.h"
 #include "src/ast/scopes.h"
@@ skipping 1181 matching lines @@
   IndentedScope indent(this, "...", node->position());
   Visit(node->expression());
 }
 
 
 void AstPrinter::VisitEmptyParentheses(EmptyParentheses* node) {
   IndentedScope indent(this, "()", node->position());
 }
 
 void AstPrinter::VisitGetIterator(GetIterator* node) {
-  IndentedScope indent(this, "GET-ITERATOR", node->position());
+  const char* desc = node->hint() == GetIterator::kAsync ? "GET-ASYNC-ITERATOR"
+                                                         : "GET-ITERATOR";
+  IndentedScope indent(this, desc, node->position());
   Visit(node->iterable());
 }
 
 void AstPrinter::VisitThisFunction(ThisFunction* node) {
   IndentedScope indent(this, "THIS-FUNCTION", node->position());
 }
 
 
 void AstPrinter::VisitSuperPropertyReference(SuperPropertyReference* node) {
   IndentedScope indent(this, "SUPER-PROPERTY-REFERENCE", node->position());
 }
 
 
 void AstPrinter::VisitSuperCallReference(SuperCallReference* node) {
   IndentedScope indent(this, "SUPER-CALL-REFERENCE", node->position());
 }
 
 
 void AstPrinter::VisitRewritableExpression(RewritableExpression* node) {
   Visit(node->expression());
 }
 
 
 #endif  // DEBUG
 
 }  // namespace internal
 }  // namespace v8