Strengthen resynthesis checks for `prefix.className.staticMember`.

pkg/analyzer/test/src/summary/resynthesize_test.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.
 
 library test.src.serialization.elements_test;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 35 matching lines @@
       new AnalysisOptionsImpl()..enableGenericMethods = true;
 
   void addLibrary(String uri) {
     otherLibrarySources.add(analysisContext2.sourceFactory.forUri(uri));
   }
 
   void addLibrarySource(String filePath, String contents) {
     otherLibrarySources.add(addNamedSource(filePath, contents));
   }
 
+  /**
+   * Verify that the given prefix is safe to elide from a resynthesized AST.
+   */
+  void checkElidablePrefix(SimpleIdentifier prefix) {
+    if (prefix.staticElement is! PrefixElement &&
+        prefix.staticElement is! ClassElement) {
+      fail('Prefix of type ${prefix.staticElement.runtimeType}'
+          ' should not have been elided');
+    }
+  }
+
   void checkLibrary(String text,
       {bool allowErrors: false, bool dumpSummaries: false}) {
     Source source = addSource(text);
     LibraryElementImpl original = resolve2(source);
     LibraryElementImpl resynthesized = resynthesizeLibraryElement(
         encodeLibrary(original,
             allowErrors: allowErrors, dumpSummaries: dumpSummaries),
         source.uri.toString(),
         original);
     checkLibraryElements(original, resynthesized);
@@ skipping 294 matching lines @@
               ' have been elided');
         }
       } else if (o is PropertyAccess &&
           o.target is PrefixedIdentifier &&
           r is PrefixedIdentifier) {
         // We don't resynthesize prefixed identifiers when the prefix refers to
         // a PrefixElement or a ClassElement.  Which means that if the original
         // expression was e.g. `prefix.topLevelVariableName.length`, it will get
         // resynthesized as `topLevelVariableName.length`
         PrefixedIdentifier oTarget = o.target;
-        if (oTarget.prefix.staticElement is PrefixElement ||
-            oTarget.prefix.staticElement is ClassElement) {
-          compareConstAsts(r,
-              AstFactory.identifier(oTarget.identifier, o.propertyName), desc);
-        } else {
-          fail('Prefix of type ${oTarget.prefix.staticElement.runtimeType}'
-              ' should not have been elided');
-        }
+        checkElidablePrefix(oTarget.prefix);
+        compareConstAsts(
+            r, AstFactory.identifier(oTarget.identifier, o.propertyName), desc);
       } else if (o is PrefixedIdentifier && r is PrefixedIdentifier) {
         compareConstAsts(r.prefix, o.prefix, desc);
         compareConstAsts(r.identifier, o.identifier, desc);
       } else if (o is PropertyAccess && r is PropertyAccess) {
         compareConstAsts(r.target, o.target, desc);
         expect(r.propertyName.name, o.propertyName.name, reason: desc);
         compareElements(
             r.propertyName.staticElement, o.propertyName.staticElement, desc);
-      } else if (o is PropertyAccess && r is SimpleIdentifier) {
-        // We don't resynthesize property access.
-        // We use simple identifiers with correct elements.
+      } else if (o is PropertyAccess &&
+          o.target is PrefixedIdentifier &&
+          r is SimpleIdentifier) {
+        // We don't resynthesize property access when it takes the form
+        // `prefixName.className.staticMember`.  We just resynthesize a
+        // SimpleIdentifier correctly resolved to the static member.
+        PrefixedIdentifier oTarget = o.target;
+        checkElidablePrefix(oTarget.prefix);
+        checkElidablePrefix(oTarget.identifier);
         compareConstAsts(r, o.propertyName, desc);
       } else if (o is NullLiteral) {
         expect(r, new isInstanceOf<NullLiteral>(), reason: desc);
       } else if (o is BooleanLiteral && r is BooleanLiteral) {
         expect(r.value, o.value, reason: desc);
       } else if (o is IntegerLiteral && r is IntegerLiteral) {
         expect(r.value, o.value, reason: desc);
       } else if (o is DoubleLiteral && r is DoubleLiteral) {
         if (r.value != null &&
             r.value.isNaN &&
@@ skipping 3580 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }