Serialize and process patch metadata

pkg/compiler/lib/src/compiler.dart

 // 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.
 
 library dart2js.compiler_base;
 
 import 'dart:async' show EventSink, Future;
 
 import '../compiler_new.dart' as api;
 import 'cache_strategy.dart' show CacheStrategy;
@@ skipping 1046 matching lines @@
                 .log('Resolved ${enqueuer.resolution.processedElements.length} '
                     'elements.');
             progress.reset();
           }
         }
         AstElement element = work.element;
         if (world.hasBeenProcessed(element)) {
           return const WorldImpact();
         }
         WorldImpact worldImpact = analyzeElement(element);
-        backend.onElementResolved(element);
         world.registerProcessedElement(element);
         return worldImpact;
       });
 
   WorldImpact codegen(CodegenWorkItem work, CodegenEnqueuer world) {
     assert(invariant(work.element, identical(world, enqueuer.codegen)));
     if (shouldPrintProgress) {
       // TODO(ahe): Add structured diagnostics to the compiler API and
       // use it to separate this from the --verbose option.
       reporter
@@ skipping 573 matching lines @@
             currentElement.enclosingClass.isEnumClass) {
           // Enums ASTs are synthesized (and give messed up messages).
           return true;
         }
 
         if (currentElement is AstElement) {
           AstElement astElement = currentElement;
           if (astElement.hasNode) {
             Token from = astElement.node.getBeginToken();
             Token to = astElement.node.getEndToken();
-            if (astElement.metadata.isNotEmpty &&
-                astElement.metadata.first.hasNode) {
+            if (astElement.metadata.isNotEmpty) {
+              if (!astElement.metadata.first.hasNode) {
+                // We might try to report an error while parsing the metadata
+                // itself.
+                return true;
+              }
               from = astElement.metadata.first.node.getBeginToken();
             }
             return validateToken(from, to);
           }
         }
         return true;
       }, message: "Invalid current element: $currentElement [$begin,$end]."));
     }
     return new SourceSpan.fromTokens(uri, begin, end);
   }
@@ skipping 428 matching lines @@
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }