Always parse 'x.y' as a prefixed identifier.

pkg/analyzer/lib/src/generated/parser.dart

 // Copyright (c) 2014, 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.src.generated.parser;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 6339 matching lines @@
           expression = astFactory.functionExpressionInvocation(
               expression, typeArguments, argumentList);
         }
         if (!primaryAllowed) {
           isOptional = false;
         }
       }
       Expression selectorExpression = parseAssignableSelector(
           expression, isOptional || (expression is PrefixedIdentifier));
       if (identical(selectorExpression, expression)) {
-        if (!isOptional && (expression is PrefixedIdentifier)) {
-          PrefixedIdentifier identifier = expression as PrefixedIdentifier;
-          expression = astFactory.propertyAccess(
-              identifier.prefix, identifier.period, identifier.identifier);
-        }
         return expression;
       }
       expression = selectorExpression;
       isOptional = true;
     }
   }
 
   /**
    * Parse a block when we need to check for an open curly brace and recover
    * when there isn't one. Return the block that was parsed.
@@ skipping 2124 matching lines @@
    */
   Parser_SyntheticKeywordToken(Keyword keyword, int offset)
       : super(keyword, offset);
 
   @override
   int get length => 0;
 
   @override
   Token copy() => new Parser_SyntheticKeywordToken(keyword, offset);
 }