Make "error" the default severity for checked mode compile time errors.

pkg/analyzer/lib/src/analyzer_impl.dart

 // Copyright (c) 2013, 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 analyzer_impl;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'generated/constant.dart';
@@ skipping 18 matching lines @@
  * The maximum number of sources for which AST structures should be kept in the cache.
  */
 const int _MAX_CACHE_SIZE = 512;
 
 DirectoryBasedDartSdk sdk;
 
 /// Analyzes single library [File].
 class AnalyzerImpl {
   /**
    * Compute the severity of the error; however, if
-   * [escalateCheckedModeCompileTimeErrors] is true, then escalate it to
-   * [ErrorSeverity.ERROR].
+   * [enableTypeChecks] is false, then de-escalate checked-mode compile time
+   * errors to a severity of [ErrorSeverity.INFO].
    */
   static ErrorSeverity computeSeverity(
-      AnalysisError error, bool escalateCheckedModeCompileTimeErrors) {
-    if (escalateCheckedModeCompileTimeErrors
+      AnalysisError error, bool enableTypeChecks) {
+    if (!enableTypeChecks
         && error.errorCode.type == ErrorType.CHECKED_MODE_COMPILE_TIME_ERROR) {
-      return ErrorSeverity.ERROR;
+      return ErrorSeverity.INFO;
     }
     return error.errorCode.errorSeverity;
   }
 
   final String sourcePath;
   final CommandLineOptions options;
   final int startTime;
 
   ContentCache contentCache = new ContentCache();
   SourceFactory sourceFactory;
@@ skipping 370 matching lines @@
     }
   }
 
   @override
   void logInformation2(String message, Exception exception) {
     if (log) {
       stdout.writeln(message);
     }
   }
 }