Make ClosureMirror handle instances of user-defined classes that implement call.

tests/lib/mirrors/fake_function_test.dart

+// 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.
+
+import "dart:mirrors";
+
+import "package:expect/expect.dart";
+
+class WannabeFunction {
+  int call(int a, int b) => a + b;
+  method(x) => x * x;
+}
+
+main() {
+  Expect.isTrue(new WannabeFunction() is Function);
+
+  ClosureMirror cm = reflect(new WannabeFunction());
+  Expect.equals(7, cm.invoke(const Symbol("call"), [3,4]).reflectee);
+  Expect.throws(() => cm.invoke(const Symbol("call"), [3]),
+                (e) => e is NoSuchMethodError,
+                "Wrong arity");
+  Expect.equals(49, cm.invoke(const Symbol("method"), [7]).reflectee);
+  Expect.throws(() => cm.invoke(const Symbol("method"), [3, 4]),
+                (e) => e is NoSuchMethodError,
+                "Wrong arity");
+  Expect.equals(7, cm.apply([3,4]).reflectee);
+  Expect.throws(() => cm.apply([3]),
+                (e) => e is NoSuchMethodError,
+                "Wrong arity");
+
+  MethodMirror mm = cm.function;
+  Expect.equals(const Symbol("call"), mm.simpleName);
+  Expect.equals(reflectClass(WannabeFunction),
+                mm.owner);
+  Expect.isTrue(mm.isRegularMethod);
+  Expect.equals(const Symbol("int"), mm.returnType.simpleName);
+  Expect.equals(const Symbol("int"), mm.parameters[0].type.simpleName);
+  Expect.equals(const Symbol("int"), mm.parameters[1].type.simpleName);
+
+  ClassMirror km = cm.type;
+  Expect.equals(reflectClass(WannabeFunction), km);
+  Expect.equals(const Symbol("WannabeFunction"), km.simpleName);
+  Expect.equals(mm, km.members[const Symbol("call")]);
+  Expect.setEquals([const Symbol("call"), const Symbol("method")],
+                   km.members.keys);
+}