Mark code when it instantiates an unloaded deferred type

runtime/vm/parser.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/parser.h"
 
 #include "lib/invocation_mirror.h"
 #include "platform/utils.h"
 #include "vm/ast_transformer.h"
 #include "vm/bootstrap.h"
@@ skipping 11892 matching lines @@
         ResolveIdentInLocalScope(ident_pos, type_name, NULL)) {
       // The type is malformed. Skip over its type arguments.
       ParseTypeArguments(ClassFinalizer::kIgnore);
       return ClassFinalizer::NewFinalizedMalformedType(
           Error::Handle(Z),  // No previous error.
           script_,
           ident_pos,
           "using '%s' in this context is invalid",
           type_name.ToCString());
     }
-    if (!prefix.IsNull() && prefix.is_deferred_load() && !allow_deferred_type) {
-      ParseTypeArguments(ClassFinalizer::kIgnore);
-      return ClassFinalizer::NewFinalizedMalformedType(
-          Error::Handle(Z),  // No previous error.
-          script_,
-          ident_pos,
-          "using deferred type '%s.%s' is invalid",
-          String::Handle(Z, prefix.name()).ToCString(),
-          type_name.ToCString());
+    if (!prefix.IsNull() && prefix.is_deferred_load()) {
+      // If deferred prefixes are allowed but it is not yet loaded,
+      // remember that this function depends on the prefix.
+      if (allow_deferred_type && !prefix.is_loaded()) {
+        ASSERT(parsed_function() != NULL);
+        parsed_function()->AddDeferredPrefix(prefix);
+      }
+      // If the deferred prefixes are not allowed, or if the prefix
+      // is not yet loaded, return a malformed type. Otherwise, handle
+      // resolution below, as needed.
+      if (!prefix.is_loaded() || !allow_deferred_type) {
+        ParseTypeArguments(ClassFinalizer::kIgnore);
+        return ClassFinalizer::NewFinalizedMalformedType(
+            Error::Handle(Z),  // No previous error.
+            script_,
+            ident_pos,
+            !prefix.is_loaded()
+                ? "deferred type '%s.%s' is not yet loaded"
+                : "using deferred type '%s.%s' is invalid",
+            String::Handle(Z, prefix.name()).ToCString(),
+            type_name.ToCString());
+      }
     }
   }
   Object& type_class = Object::Handle(Z);
   // Leave type_class as null if type finalization mode is kIgnore.
   if (finalization != ClassFinalizer::kIgnore) {
     type_class = UnresolvedClass::New(prefix, type_name, ident_pos);
   }
   TypeArguments& type_arguments = TypeArguments::Handle(
       Z, ParseTypeArguments(finalization));
   if (finalization == ClassFinalizer::kIgnore) {
@@ skipping 1473 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart