Add tests for generic methods in strong mode

tests/language_strong/generic_methods_unused_parameter_test.dart

+// Copyright (c) 2017, 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 generic_methods_unused_parameter_test;
+
+import "package:expect/expect.dart";
+
+typedef Fun = int Function();
+typedef FunReq = int Function(int);
+typedef FunOpt = int Function([int]);
+typedef FunReqOpt = int Function(int, [int]);
+typedef FunNam = int Function({int p});
+typedef FunReqNam = int Function(int, {int p});
+
+typedef FunTyp = int Function<T>();
+typedef FunTypReq = int Function<T>(int);
+typedef FunTypOpt = int Function<T>([int]);
+typedef FunTypReqOpt = int Function<T>(int, [int]);
+typedef FunTypNam = int Function<T>({int p});
+typedef FunTypReqNam = int Function<T>(int, {int p});
+
+int fun() {}
+int funReq(int x) => x;
+int funOpt([int y]) => y ?? 42;
+int funReqOpt(int x, [int y]) => x;
+int funNam({int p}) => p ?? 42;
+int funReqNam(int x, {int p}) => x;
+
+int funTyp<T>() {}
+int funTypReq<T>(int x) => x;
+int funTypOpt<T>([int y]) => y ?? 42;
+int funTypReqOpt<T>(int x, [int y]) => x;
+int funTypNam<T>({int p}) => p ?? 42;
+int funTypReqNam<T>(int x, {int p}) => x;
+
+main() {
+  Fun varFun = funTyp;

[eernst, 2017/03/09 14:55:03]

Agreeing with Leaf, I'll assume that you meant to use the types Fun (in line
38), FunReq (line 39), etc.

If so, this is all about obtaining an instantiation of the generic functions
(`varFun` refers to `funTyp<dynamic>`, etc).

A comment explaining this in a few words would be good for readability and
maintenance.

[Dmitry Stefantsov, 2017/03/10 13:21:55]

Yes, I put the wrong types in lines 39-43 here. Also agree about comments.

+  Fun varFunReq = funTypReq;

[Leaf, 2017/03/09 05:51:19]

I think the LHS types here are wrong.  Presumably should be Fun, FunReq, ....?

[Dmitry Stefantsov, 2017/03/10 13:21:55]

Yes, exactly.

+  Fun varFunOpt = funTypOpt;
+  Fun varFunReqOpt = funTypReqOpt;
+  Fun varFunNam = funTypNam;
+  Fun varFunReqNam = funTypReqNam;
+
+  Expect.isTrue(fun is Fun);
+  Expect.isTrue(fun is! FunTyp);
+  Expect.isTrue(funTyp is! Fun);
+  Expect.isTrue(funTyp is FunTyp);
+  Expect.isTrue(varFun is Fun);
+  Expect.isTrue(varFun is! FunTyp);
+
+  Expect.isTrue(funReq is FunReq);
+  Expect.isTrue(funReq is! FunTypReq);
+  Expect.isTrue(funTypReq is! FunReq);
+  Expect.isTrue(funTypReq is FunTypReq);
+  Expect.isTrue(varFunReq is FunReq);
+  Expect.isTrue(varFunReq is! FunTypReq);
+
+  Expect.isTrue(funOpt is FunOpt);
+  Expect.isTrue(funOpt is! FunTypOpt);
+  Expect.isTrue(funTypOpt is! FunOpt);
+  Expect.isTrue(funTypOpt is FunTypOpt);
+  Expect.isTrue(varFunOpt is FunOpt);
+  Expect.isTrue(varFunOpt is! FunTypOpt);
+
+  Expect.isTrue(funReqOpt is FunReqOpt);
+  Expect.isTrue(funReqOpt is! FunTypReqOpt);
+  Expect.isTrue(funTypReqOpt is! FunReqOpt);
+  Expect.isTrue(funTypReqOpt is FunTypReqOpt);
+  Expect.isTrue(varFunReqOpt is FunReqOpt);
+  Expect.isTrue(varFunReqOpt is! FunTypReqOpt);
+
+  Expect.isTrue(funNam is FunNam);
+  Expect.isTrue(funNam is! FunTypNam);
+  Expect.isTrue(funTypNam is! FunNam);
+  Expect.isTrue(funTypNam is FunTypNam);
+  Expect.isTrue(varFunNam is FunNam);
+  Expect.isTrue(varFunNam is! FunTypNam);
+
+  Expect.isTrue(funReqNam is FunReqNam);
+  Expect.isTrue(funReqNam is! FunTypReqNam);
+  Expect.isTrue(funTypReqNam is! FunReqNam);
+  Expect.isTrue(funTypReqNam is FunTypReqNam);
+  Expect.isTrue(varFunReqNam is FunReqNam);
+  Expect.isTrue(varFunReqNam is! FunTypReqNam);
+}