Use predicates to check simple function types.

tests/language/function_subtype_simple2_test.dart

Index: tests/language/function_subtype_simple2_test.dart
diff --git a/tests/language/function_subtype_simple2_test.dart b/tests/language/function_subtype_simple2_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..70f53f3392411521f7b518f946fa7b7479d66047
--- /dev/null
+++ b/tests/language/function_subtype_simple2_test.dart
@@ -0,0 +1,74 @@
+// Copyright (c) 2013, 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.
+// Dart test program for constructors and initializers.
+
+// Check function subtyping of simple function types.
+
+import 'package:expect/expect.dart';
+
+typedef Args0();
+typedef Args1(a);
+typedef Args2(a, b);
+typedef Args3(a, b, c);
+typedef Args4(a, b, c, d);
+
+args0_1([a]) {}
+args1_2(a, [b]) {}
+args0_2([a, b]) {}
+args1_3(a, [b, c]) {}
+
+args0_1_named({a}) {}
+args1_2_named(a, {b}) {}
+args0_2_named({a, b}) {}
+args1_3_named(a, {b, c}) {}
+
+main() {
+  Expect.isTrue(args0_1 is Args0);
+  Expect.isTrue(args0_1 is Args1);
+  Expect.isFalse(args0_1 is Args2);
+  Expect.isFalse(args0_1 is Args3);
+  Expect.isFalse(args0_1 is Args4);
+
+  Expect.isFalse(args1_2 is Args0);
+  Expect.isTrue(args1_2 is Args1);
+  Expect.isTrue(args1_2 is Args2);
+  Expect.isFalse(args1_2 is Args3);
+  Expect.isFalse(args1_2 is Args4);
+
+  Expect.isTrue(args0_2 is Args0);
+  Expect.isTrue(args0_2 is Args1);
+  Expect.isTrue(args0_2 is Args2);
+  Expect.isFalse(args0_2 is Args3);
+  Expect.isFalse(args0_2 is Args4);
+
+  Expect.isFalse(args1_3 is Args0);
+  Expect.isTrue(args1_3 is Args1);
+  Expect.isTrue(args1_3 is Args2);
+  Expect.isTrue(args1_3 is Args3);
+  Expect.isFalse(args1_3 is Args4);
+
+  Expect.isTrue(args0_1_named is Args0);
+  Expect.isFalse(args0_1_named is Args1);
+  Expect.isFalse(args0_1_named is Args2);
+  Expect.isFalse(args0_1_named is Args3);
+  Expect.isFalse(args0_1_named is Args4);
+
+  Expect.isFalse(args1_2_named is Args0);
+  Expect.isTrue(args1_2_named is Args1);
+  Expect.isFalse(args1_2_named is Args2);
+  Expect.isFalse(args1_2_named is Args3);
+  Expect.isFalse(args1_2_named is Args4);
+
+  Expect.isTrue(args0_2_named is Args0);
+  Expect.isFalse(args0_2_named is Args1);
+  Expect.isFalse(args0_2_named is Args2);
+  Expect.isFalse(args0_2_named is Args3);
+  Expect.isFalse(args0_2_named is Args4);
+
+  Expect.isFalse(args1_3_named is Args0);
+  Expect.isTrue(args1_3_named is Args1);
+  Expect.isFalse(args1_3_named is Args2);
+  Expect.isFalse(args1_3_named is Args3);
+  Expect.isFalse(args1_3_named is Args4);
+}