add tests to demonstrate missing generic function subtype logic

pkg/analyzer/test/src/task/strong/strong_test_helper.dart

 // Copyright (c) 2015, 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.
 
 // TODO(jmesserly): this file needs to be refactored, it's a port from
 // package:dev_compiler's tests
 library test.src.task.strong.strong_test_helper;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
@@ skipping 155 matching lines @@
     // Use error marker found in an immediately preceding comment,
     // and attach it to the outermost expression that starts at that token.
     if (comment != null) {
       while (comment.next != null) {
         comment = comment.next;
       }
       if (comment.end == token.offset && node.parent.beginToken != token) {
         var commentText = '$comment';
         var start = commentText.lastIndexOf('/*');
         var end = commentText.lastIndexOf('*/');
-        if (start != -1 && end != -1) {
+        if (start != -1 &&
+            end != -1 &&
+            !commentText.startsWith('/*<', start) &&
+            !commentText.startsWith('/*=', start)) {
           expect(start, lessThan(end));
           var errors = commentText.substring(start + 2, end).split(',');
           var expectations =
               errors.map(_ErrorExpectation.parse).where((x) => x != null);
 
-          for (var e in expectations) _expectError(node, e);
+          for (var e in expectations) {
+            _expectError(node, e);
+          }
         }
       }
     }
     return super.visitNode(node);
   }
 
   void _expectError(AstNode node, _ErrorExpectation expected) {
     // See if we can find the expected error in our actual errors
     for (var actual in _actualErrors) {
       if (actual.offset == node.offset && actual.length == node.length) {
@@ skipping 311 matching lines @@
   if (levelName == 'warning') return _MAGENTA_COLOR;
   if (levelName == 'info') return _CYAN_COLOR;
   return null;
 }
 
 const String _RED_COLOR = '\u001b[31m';
 const String _MAGENTA_COLOR = '\u001b[35m';
 const String _CYAN_COLOR = '\u001b[36m';
 const String GREEN_COLOR = '\u001b[32m';
 const String NO_COLOR = '\u001b[0m';