Support patched generic methods.

tests/compiler/dart2js/patch_test.dart

 // Copyright (c) 2012, 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 'dart:async';
 import 'package:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/diagnostics/messages.dart' show MessageKind;
 import 'package:compiler/src/elements/elements.dart';
@@ skipping 148 matching lines @@
       collector.warnings.isEmpty, "Unexpected warnings: ${collector.warnings}");
   Expect.isTrue(
       collector.errors.isEmpty, "Unexpected errors: ${collector.errors}");
 
   Expect.equals(1, origin.metadata.length,
       "Unexpected origin metadata: ${origin.metadata}.");
   Expect.equals(3, patch.metadata.length,
       "Unexpected patch metadata: ${patch.metadata}.");
 }
 
+Future testPatchFunctionGeneric() async {
+  var compiler = await applyPatch(
+      "external T test<T>();", "@patch T test<T>() { return null; } ");
+  Element origin = ensure(
+      compiler, "test", compiler.commonElements.coreLibrary.find,
+      expectIsPatched: true, checkHasBody: true);
+  ensure(compiler, "test", compiler.commonElements.coreLibrary.patch.find,
+      expectIsPatch: true, checkHasBody: true);
+  compiler.resolver.resolve(origin);
+
+  DiagnosticCollector collector = compiler.diagnosticCollector;
+  Expect.isTrue(
+      collector.warnings.isEmpty, "Unexpected warnings: ${collector.warnings}");
+  Expect.isTrue(
+      collector.errors.isEmpty, "Unexpected errors: ${collector.errors}");
+}
+
+Future testPatchFunctionGenericExtraTypeVariable() async {
+  var compiler = await applyPatch(
+      "external T test<T>();", "@patch T test<T, S>() { return null; } ");
+  Element origin = ensure(
+      compiler, "test", compiler.commonElements.coreLibrary.find,
+      expectIsPatched: true, checkHasBody: true);
+  ensure(compiler, "test", compiler.commonElements.coreLibrary.patch.find,
+      expectIsPatch: true, checkHasBody: true);
+  compiler.resolver.resolve(origin);
+
+  DiagnosticCollector collector = compiler.diagnosticCollector;
+  Expect.isTrue(
+      collector.warnings.isEmpty, "Unexpected warnings: ${collector.warnings}");
+  Expect.equals(1, collector.errors.length);
+  Expect.isTrue(collector.errors.first.message.kind ==
+      MessageKind.PATCH_TYPE_VARIABLES_MISMATCH);
+}
+
+Future testPatchFunctionGenericDifferentNames() async {
+  var compiler = await applyPatch(
+      "external T test<T, S>();", "@patch T test<S, T>() { return null; } ");
+  Element origin = ensure(
+      compiler, "test", compiler.commonElements.coreLibrary.find,
+      expectIsPatched: true, checkHasBody: true);
+  ensure(compiler, "test", compiler.commonElements.coreLibrary.patch.find,
+      expectIsPatch: true, checkHasBody: true);
+  compiler.resolver.resolve(origin);
+
+  DiagnosticCollector collector = compiler.diagnosticCollector;
+  Expect.isTrue(
+      collector.warnings.isEmpty, "Unexpected warnings: ${collector.warnings}");
+  Expect.equals(1, collector.errors.length);
+  Expect.isTrue(collector.errors.first.message.kind ==
+      MessageKind.PATCH_TYPE_VARIABLES_MISMATCH);
+}
+
 Future testPatchVersioned() async {
   String fullPatch = "test(){return 'string';}";
   String lazyPatch = "test(){return 'new and improved string';}";
 
   String patchSource = """
       @patch_full $fullPatch
       @patch_lazy $lazyPatch
       """;
 
   Future test(String patchVersion,
@@ skipping 900 matching lines @@
   compareWarningKinds(
       patchText, [MessageKind.NOT_ASSIGNABLE], collector.warnings);
 }
 
 main() {
   asyncTest(() async {
     await testPatchConstructor();
     await testPatchRedirectingConstructor();
     await testPatchFunction();
     await testPatchFunctionMetadata();
+    await testPatchFunctionGeneric();
+    await testPatchFunctionGenericExtraTypeVariable();
+    await testPatchFunctionGenericDifferentNames();
     await testPatchMember();
     await testPatchGetter();
     await testRegularMember();
     await testInjectedMember();
     await testInjectedPublicMember();
     await testInjectedFunction();
     await testInjectedPublicFunction();
     await testPatchSignatureCheck();
 
     await testPatchVersioned();
@@ skipping 17 matching lines @@
     await testPatchNonFunction();
 
     await testPatchAndSelector();
 
     await testEffectiveTarget();
 
     await testAnalyzeAllInjectedMembers();
     await testTypecheckPatchedMembers();
   });
 }