cascade target fix and common test

pkg/analysis_server/test/services/completion/completion_test_util.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 test.services.completion.util;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart' as protocol show Element,
     ElementKind;
@@ skipping 379 matching lines @@
   CompletionSuggestion assertSuggestLocalClass(String name,
       [CompletionRelevance relevance = CompletionRelevance.DEFAULT]) {
     if (computer is LocalComputer) {
       return assertSuggestClass(name, relevance);
     } else {
       return assertNotSuggested(name);
     }
   }
 
   test_Block() {
+    // Block  BlockFunctionBody  MethodDeclaration
     addSource('/testAB.dart', '''
       class A {int x;}
       class _B { }''');
     addSource('/testCD.dart', '''
       class C { }
       class D { }''');
     addSource('/testEEF.dart', '''
       class EE { }
       class F { }''');
     addSource('/testG.dart', 'class G { }');
@@ skipping 28 matching lines @@
       assertSuggestLibraryPrefix('g');
       assertNotSuggested('G');
       assertSuggestImportedClass('H', CompletionRelevance.LOW);
       assertSuggestImportedClass('Object');
       // TODO (danrubel) suggest HtmlElement as low relevance
       assertNotSuggested('HtmlElement');
     });
   }
 
   test_CascadeExpression_selector1() {
+    // PropertyAccess  CascadeExpression  ExpressionStatement  Block
     addSource('/testB.dart', '''
       class B { }''');
     addTestSource('''
       import "/testB.dart";
       class A {var b; X _c;}
       class X{}
       // looks like a cascade to the parser
       // but the user is trying to get completions for a non-cascade
       main() {A a; a.^.z}''');
     computeFast();
     return computeFull(true).then((_) {
       assertSuggestInvocationGetter('b', null);
       assertSuggestInvocationGetter('_c', 'X');
       assertNotSuggested('Object');
       assertNotSuggested('A');
       assertNotSuggested('B');
       assertNotSuggested('X');
       assertNotSuggested('z');
     });
   }
 
   test_CascadeExpression_selector2() {
+    // SimpleIdentifier  PropertyAccess  CascadeExpression  ExpressionStatement
     addSource('/testB.dart', '''
       class B { }''');
     addTestSource('''
       import "/testB.dart";
       class A {var b; X _c;}
       class X{}
       main() {A a; a..^z}''');
     computeFast();
-    assertNoSuggestions();
     return computeFull(true).then((_) {
       assertSuggestInvocationGetter('b', null);
       assertSuggestInvocationGetter('_c', 'X');
       assertNotSuggested('Object');
       assertNotSuggested('A');
       assertNotSuggested('B');
       assertNotSuggested('X');
       assertNotSuggested('z');
     });
   }
+
+  test_CascadeExpression_target() {
+    // SimpleIdentifier  CascadeExpression  ExpressionStatement
+    addTestSource('''
+      class A {var b; X _c;}
+      class X{}
+      main() {A a; a^..b}''');
+    computeFast();
+    return computeFull(true).then((_) {
+      assertNotSuggested('b');
+      assertNotSuggested('_c');
+      assertSuggestLocalVariable('a', 'A');
+      assertSuggestLocalClass('A');
+      assertSuggestLocalClass('X');
+      assertSuggestImportedClass('Object');
+    });
+  }
 }