Fix parser in case of unmatched angle bracket.

sdk/lib/_internal/compiler/implementation/scanner/parser.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 scanner;
 
 /**
  * An event generating parser of Dart programs. This parser expects
  * all tokens in a linked list (aka a token stream).
  *
@@ skipping 682 matching lines @@
         if (optional('.', token.next)) {
           // type '.' ...
           if (token.next.next.isIdentifier()) {
             // type '.' identifier
             token = token.next.next;
           }
         }
         if (optional('<', token.next)) {
           if (token.next is BeginGroupToken) {
             BeginGroupToken beginGroup = token.next;
+            if (beginGroup.endGroup == null) {
+              listener.unmatched(beginGroup);
+            }
             token = beginGroup.endGroup;
           }
         }
       }
       token = token.next;
     }
     return listener.expectedDeclaration(start);
   }
 
   Token parseVariableInitializerOpt(Token token) {
@@ skipping 1482 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }