Filter out AnalysisErrors with null 'errorCode'.

pkg/analyzer/lib/src/dart/analysis/driver.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:typed_data';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart' show CompilationUnitElement;
@@ skipping 698 matching lines @@
   }
 
   /**
    * Load the [AnalysisResult] for the given [file] from the [bytes]. Set
    * optional [content] and [resolvedUnit].
    */
   AnalysisResult _getAnalysisResultFromBytes(
       FileState libraryFile, FileState file, List<int> bytes,
       {String content, CompilationUnit resolvedUnit}) {
     var unit = new AnalysisDriverResolvedUnit.fromBuffer(bytes);
-    List<AnalysisError> errors = unit.errors
-        .map((error) => new AnalysisError.forValues(
-            file.source,
-            error.offset,
-            error.length,
-            errorCodeByUniqueName(error.uniqueName),
-            error.message,
-            error.correction))
-        .toList();
+    List<AnalysisError> errors = unit.errors.map((error) {
+      String errorName = error.uniqueName;
+      ErrorCode errorCode = errorCodeByUniqueName(errorName);
+      if (errorCode == null) {
+        throw new StateError('No ErrorCode for $errorName in $file');
+      }
+      return new AnalysisError.forValues(file.source, error.offset,
+          error.length, errorCode, error.message, error.correction);
+    }).toList();
     return new AnalysisResult(
         libraryFile,
         file,
         _sourceFactory,
         file.path,
         file.uri,
         content,
         file.contentHash,
         file.lineInfo,
         resolvedUnit,
@@ skipping 550 matching lines @@
 }
 
 /**
  * TODO(scheglov) document
  */
 class _LibraryContext {
   final FileState file;
   final SummaryDataStore store;
   _LibraryContext(this.file, this.store);
 }