Support code completion in cast patterns

Change-Id: I429957a44bdc09a0936c10123b58b3514b23e016
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/279563
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/test/client/completion_driver_test.dart

@@ -96,12 +96,16 @@ abstract class AbstractCompletionDriverTest
     final actual = buffer.toString();
 
     if (actual != expected) {
-      // TODO(brianwilkerson) Improve the output to make it easier to debug. For
-      //  example, print the type of the covering node and the `entity` used to
-      //  compute the suggestions.
+      var target = driver.server.server.completionState.currentRequest?.target;
+      var where = '';
+      if (target != null) {
+        var containingNode = target.containingNode.runtimeType;
+        var entity = target.entity;
+        where = ' (containingNode = $containingNode, entity = $entity)';
+      }
       TextExpectationsCollector.add(actual);
       fail('''
-The actual suggestions do not match the expected suggestions.
+The actual suggestions do not match the expected suggestions$where.
 
 To accept the current state change the expectation to
 

pkg/analysis_server/test/services/completion/dart/local_reference_contributor_test.dart

@@ -5849,7 +5849,6 @@ class C<T> {
     assertNotSuggested('String');
   }
 
-  @FailingTest(issue: 'https://github.com/dart-lang/sdk/issues/49759')
   Future<void> test_SwitchStatement_case_var() async {
     // SwitchStatement  Block  BlockFunctionBody  MethodDeclaration
     addTestSource('''

pkg/analysis_server/test/services/completion/dart/location/cast_pattern_test.dart

@@ -0,0 +1,81 @@
+// Copyright (c) 2023, 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.
+
+import 'package:analysis_server/src/protocol_server.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import '../../../../client/completion_driver_test.dart';
+import '../completion_printer.dart' as printer;
+
+void main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(CastPatternTest1);
+    defineReflectiveTests(CastPatternTest2);
+  });
+}
+
+@reflectiveTest
+class CastPatternTest1 extends AbstractCompletionDriverTest
+    with CastPatternTestCases {
+  @override
+  TestingCompletionProtocol get protocol => TestingCompletionProtocol.version1;
+}
+
+@reflectiveTest
+class CastPatternTest2 extends AbstractCompletionDriverTest
+    with CastPatternTestCases {
+  @override
+  TestingCompletionProtocol get protocol => TestingCompletionProtocol.version2;
+}
+
+mixin CastPatternTestCases on AbstractCompletionDriverTest {
+  @override
+  Future<void> setUp() async {
+    await super.setUp();
+
+    printerConfiguration = printer.Configuration(
+      filter: (suggestion) {
+        final completion = suggestion.completion;
+        return suggestion.kind == CompletionSuggestionKind.KEYWORD ||
+            ['A0', 'B0'].any(completion.startsWith);
+      },
+    );
+  }
+
+  Future<void> test_partialType() async {
+    await computeSuggestions('''
+void f(Object x) {
+  switch (x) {
+    case i as A^
+  }
+}
+class A01 {}
+class A02 {}
+class B01 {}
+''');
+    if (isProtocolVersion2) {
+      assertResponse('''
+replacement
+  left: 1
+suggestions
+  A01
+    kind: class
+  A02
+    kind: class
+''');
+    } else {
+      assertResponse('''
+replacement
+  left: 1
+suggestions
+  A01
+    kind: class
+  A02
+    kind: class
+  B01
+    kind: class
+''');
+    }
+  }
+}

pkg/analysis_server/test/services/completion/dart/location/switch_pattern_case_test.dart

@@ -37,7 +37,9 @@ mixin SwitchPatternCaseTestCases on AbstractCompletionDriverTest {
     // TODO(brianwilkerson) Include more than keywords in these tests.
     printerConfiguration = printer.Configuration(
       filter: (suggestion) {
-        return suggestion.kind == CompletionSuggestionKind.KEYWORD;
+        final completion = suggestion.completion;
+        return suggestion.kind == CompletionSuggestionKind.KEYWORD ||
+            ['A0', 'B0'].any(completion.startsWith);
       },
     );
   }
@@ -50,33 +52,38 @@ void f(Object o) {
       return;
   }
 }
+class A01 {}
 ''');
     assertResponse('''
 suggestions
-  assert
-    kind: keyword
   break
     kind: keyword
+  return
+    kind: keyword
+  if
+    kind: keyword
+  A01
+    kind: class
+  final
+    kind: keyword
+  for
+    kind: keyword
+  throw
+    kind: keyword
+  A01
+    kind: constructorInvocation
+  assert
+    kind: keyword
   const
     kind: keyword
   do
     kind: keyword
   dynamic
     kind: keyword
-  final
-    kind: keyword
-  for
-    kind: keyword
-  if
-    kind: keyword
   late
     kind: keyword
-  return
-    kind: keyword
   switch
     kind: keyword
-  throw
-    kind: keyword
   try
     kind: keyword
   var
@@ -296,6 +303,51 @@ suggestions
     kind: keyword
   when
     kind: keyword
+''');
+  }
+
+  Future<void> test_noColon_afterDeclarationAndAs() async {
+    await computeSuggestions('''
+void f(Object x) {
+  switch (x) {
+    case var i as ^
+  }
+}
+class A01 {}
+class A02 {}
+class B01 {}
+''');
+    assertResponse('''
+suggestions
+  A01
+    kind: class
+  A02
+    kind: class
+  B01
+    kind: class
+''');
+  }
+
+  Future<void> test_noColon_afterReferenceAndAs() async {
+    await computeSuggestions('''
+void f(Object x) {
+  const i = 0;
+  switch (x) {
+    case i as ^
+  }
+}
+class A01 {}
+class A02 {}
+class B01 {}
+''');
+    assertResponse('''
+suggestions
+  A01
+    kind: class
+  A02
+    kind: class
+  B01
+    kind: class
 ''');
   }
 }

pkg/analysis_server/test/services/completion/dart/location/test_all.dart

@@ -6,6 +6,7 @@ import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'block_test.dart' as block;
 import 'case_clause_test.dart' as case_clause;
+import 'cast_pattern_test.dart' as cast_pattern;
 import 'class_body_test.dart' as class_body;
 import 'compilation_unit_test.dart' as compilation_unit;
 import 'directive_uri_test.dart' as directive_uri;
@@ -26,6 +27,7 @@ void main() {
   defineReflectiveSuite(() {
     block.main();
     case_clause.main();
+    cast_pattern.main();
     class_body.main();
     compilation_unit.main();
     directive_uri.main();

pkg/analyzer_plugin/lib/src/utilities/completion/optype.dart

@@ -350,6 +350,14 @@ class _OpTypeAstVisitor extends GeneralizingAstVisitor<void> {
     }
   }
 
+  @override
+  void visitCastPattern(CastPattern node) {
+    if (identical(entity, node.type)) {
+      optype.completionLocation = 'CastPattern_type';
+      optype.includeTypeNameSuggestions = true;
+    }
+  }
+
   @override
   void visitCatchClause(CatchClause node) {
     if (identical(entity, node.exceptionType)) {
@@ -1317,6 +1325,25 @@ class _OpTypeAstVisitor extends GeneralizingAstVisitor<void> {
     }
   }
 
+  @override
+  void visitSwitchPatternCase(SwitchPatternCase node) {
+    if (identical(entity, node.colon)) {
+      var guardedPattern = node.guardedPattern;
+      var pattern = guardedPattern.pattern;
+      if (guardedPattern.whenClause == null &&
+          pattern is DeclaredVariablePattern &&
+          pattern.name.lexeme == 'as') {
+        optype.completionLocation = 'CastPattern_type';
+        optype.includeTypeNameSuggestions = true;
+      }
+    } else if (node.statements.contains(entity)) {
+      optype.completionLocation = 'SwitchMember_statement';
+      optype.includeReturnValueSuggestions = true;
+      optype.includeTypeNameSuggestions = true;
+      optype.includeVoidReturnSuggestions = true;
+    }
+  }
+
   @override
   void visitSwitchStatement(SwitchStatement node) {
     if (identical(entity, node.expression)) {