Improved error messages for type mismatches.

pkg/unittest/lib/src/core_matchers.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.
 
 part of matcher;
 
 /**
  * Returns a matcher that matches empty strings, maps or iterables
  * (including collections).
  */
@@ skipping 159 matching lines @@
               }
             }
           }
         }
       } else {
         reason = new StringDescription();
         var eType = typeName(expected);
         var aType = typeName(actual);
         var includeTypes = eType != aType;
         // If we have recursed, show the expected value too; if not,
-        // expect() will show it for us. As expect will not show type
-        // mismatches at the top level we handle those here too.
-        if (includeTypes || depth > 1) {
+        // expect() will show it for us.
+        if (depth > 0) {
           reason.add('expected ');
           if (includeTypes) {
             reason.add(eType).add(':');
           }
           reason.addDescriptionOf(expected).add(' but ');
         }
         reason.add('was ');
         if (includeTypes) {
           reason.add(aType).add(':');
         }
         reason.addDescriptionOf(actual);
+        if (includeTypes && depth == 0) {
+          reason.add(' (not type ').add(eType).add(')');
+        }
       }
     }
     if (reason != null && location.length > 0) {
       reason.add(' ').add(location);
     }
     return reason;
   }
 
   String typeName(x) {
     // dart2js blows up on some objects (e.g. window.navigator).
@@ skipping 519 matching lines @@
       description.add(_featureDescription).add(' ').addDescriptionOf(_matcher);
 
   Description describeMismatch(item, Description mismatchDescription,
                                MatchState matchState, bool verbose) {
     mismatchDescription.add(_featureName).add(' ');
     _matcher.describeMismatch(matchState.state['feature'], mismatchDescription,
         matchState.state['innerState'], verbose);
     return mismatchDescription;
   }
 }