improve completions in closures and switch statements

pkg/analysis_server/test/services/completion/dart/optype_test.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.contributor.dart.optype;
 
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_target.dart';
 import 'package:analysis_server/src/services/completion/dart/optype.dart';
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 124 matching lines @@
     addTestSource('void main() {int.parse("16", ^)}', resolved: true);
     assertOpType(namedArgs: true);
   }
 
   test_AsExpression() {
     // SimpleIdentifier  TypeName  AsExpression
     addTestSource('class A {var b; X _c; foo() {var a; (a as ^).foo();}');
     assertOpType(typeNames: true);
   }
 
+  test_AsIdentifier() {
+    addTestSource('class A {var asdf; foo() {as^}');
+    assertOpType(returnValue: true, typeNames: true, voidReturn: true);
+  }
+
+  test_AsIdentifier2() {
+    addTestSource('class A {var asdf; foo() {A as^}');
+    assertOpType();
+  }
+
   test_Assert() {
     addTestSource('main() {assert(^)}');
     assertOpType(returnValue: true, typeNames: true);
   }
 
   test_AssignmentExpression_name() {
     // SimpleIdentifier  VariableDeclaration  VariableDeclarationList
     // VariableDeclarationStatement  Block
     addTestSource('class A {} main() {int a; int ^b = 1;}');
     assertOpType(varNames: true);
@@ skipping 1197 matching lines @@
     addTestSource('main() {switch(k) {^}}');
     assertOpType();
   }
 
   test_SwitchStatement_body_end() {
     // Token('}')  SwitchStatement  Block
     addTestSource('main() {switch(k) {case 1:^}}');
     assertOpType(returnValue: true, typeNames: true, voidReturn: true);
   }
 
+  test_SwitchStatement_body_end2() {
+    addTestSource('main() {switch(k) {case 1:as^}}');
+    assertOpType(returnValue: true, typeNames: true, voidReturn: true);
+  }
+
   test_SwitchStatement_expression1() {
     // SimpleIdentifier  SwitchStatement  Block
     addTestSource('main() {switch(^k) {case 1:{}}}');
     assertOpType(returnValue: true, typeNames: true);
   }
 
   test_SwitchStatement_expression2() {
     // SimpleIdentifier  SwitchStatement  Block
     addTestSource('main() {switch(k^) {case 1:{}}}');
     assertOpType(returnValue: true, typeNames: true);
@@ skipping 180 matching lines @@
   bool get isInSystemLibrary => false;
 
   @override
   String get shortName => fullName;
 
   @override
   Source get source => this;
 
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }