Add TypeMirror.isSubtypeOf, TypeMirror.isAssignableTo, ClassMirror.isSubclassOf

tests/lib/mirrors/relation_assignable_test.dart

+// Copyright (c) 2014, 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 Superclass {}
+class Subclass1 extends Superclass {}
+class Subclass2 extends Superclass {}
+
+typedef bool NumberPredicate(num x);
+typedef bool IntegerPredicate(int x);
+typedef bool DoublePredicate(double x);
+
+typedef num NumberGenerator();
+typedef int IntegerGenerator();
+typedef double DoubleGenerator();
+
+class A<T> {}
+class B<T> extends A<T> {}
+class C<T extends num> {}
+
+main() {
+  // Classes.
+  TypeMirror Super = reflectType(Superclass);
+  TypeMirror Sub1 = reflectType(Subclass1);
+  TypeMirror Sub2 = reflectType(Subclass2);
+  TypeMirror Obj = reflectType(Object);
+
+  Expect.isTrue(Obj.isAssignableTo(Obj));
+  Expect.isTrue(Super.isAssignableTo(Super));
+  Expect.isTrue(Sub1.isAssignableTo(Sub1));
+  Expect.isTrue(Sub2.isAssignableTo(Sub2));
+
+  Expect.isTrue(Sub1.isAssignableTo(Super));
+  Expect.isTrue(Super.isAssignableTo(Sub1));
+
+  Expect.isTrue(Sub2.isAssignableTo(Super));
+  Expect.isTrue(Super.isAssignableTo(Sub2));
+
+  Expect.isFalse(Sub2.isAssignableTo(Sub1));
+  Expect.isFalse(Sub1.isAssignableTo(Sub2));
+
+  Expect.isTrue(Sub1.isAssignableTo(Obj));
+  Expect.isTrue(Obj.isAssignableTo(Sub1));
+
+  Expect.isTrue(Sub2.isAssignableTo(Obj));
+  Expect.isTrue(Obj.isAssignableTo(Sub2));
+
+  Expect.isTrue(Super.isAssignableTo(Obj));
+  Expect.isTrue(Obj.isAssignableTo(Super));
+
+
+  // Function typedef - argument type.
+  TypeMirror Func = reflectType(Function);
+  TypeMirror NumPred = reflectType(NumberPredicate);
+  TypeMirror IntPred = reflectType(IntegerPredicate);
+  TypeMirror DubPred = reflectType(DoublePredicate);
+
+  Expect.isTrue(Func.isAssignableTo(Func));
+  Expect.isTrue(NumPred.isAssignableTo(NumPred));
+  Expect.isTrue(IntPred.isAssignableTo(IntPred));
+  Expect.isTrue(DubPred.isAssignableTo(DubPred));
+
+  Expect.isTrue(NumPred.isAssignableTo(Func));
+  Expect.isTrue(NumPred.isAssignableTo(IntPred));
+  Expect.isTrue(NumPred.isAssignableTo(DubPred));
+
+  Expect.isTrue(IntPred.isAssignableTo(Func));
+  Expect.isTrue(IntPred.isAssignableTo(NumPred));
+  Expect.isFalse(IntPred.isAssignableTo(DubPred));
+
+  Expect.isTrue(DubPred.isAssignableTo(Func));
+  Expect.isTrue(DubPred.isAssignableTo(NumPred));
+  Expect.isFalse(DubPred.isAssignableTo(IntPred));
+
+  Expect.isTrue(Func.isAssignableTo(Obj));
+  Expect.isTrue(NumPred.isAssignableTo(Obj));
+  Expect.isTrue(IntPred.isAssignableTo(Obj));
+  Expect.isTrue(DubPred.isAssignableTo(Obj));

[gbracha, 2014/01/11 01:53:30]

I hesitate to suggest more cases, but the reverse is also true:
Obj.isAssignableTo(DubPred) etc.

+
+
+  // Function typedef - return type.
+  TypeMirror NumGen = reflectType(NumberGenerator);
+  TypeMirror IntGen = reflectType(IntegerGenerator);
+  TypeMirror DubGen = reflectType(DoubleGenerator);
+
+  Expect.isTrue(NumGen.isAssignableTo(NumGen));
+  Expect.isTrue(IntGen.isAssignableTo(IntGen));
+  Expect.isTrue(DubGen.isAssignableTo(DubGen));
+
+  Expect.isTrue(NumGen.isAssignableTo(Func));
+  Expect.isTrue(NumGen.isAssignableTo(IntGen));
+  Expect.isTrue(NumGen.isAssignableTo(DubGen));
+
+  Expect.isTrue(IntGen.isAssignableTo(Func));
+  Expect.isTrue(IntGen.isAssignableTo(NumGen));
+  Expect.isFalse(IntGen.isAssignableTo(DubGen));
+
+  Expect.isTrue(DubGen.isAssignableTo(Func));
+  Expect.isTrue(DubGen.isAssignableTo(NumGen));
+  Expect.isFalse(DubGen.isAssignableTo(IntGen));
+
+  Expect.isTrue(Func.isAssignableTo(Obj));
+  Expect.isTrue(NumGen.isAssignableTo(Obj));
+  Expect.isTrue(IntGen.isAssignableTo(Obj));
+  Expect.isTrue(DubGen.isAssignableTo(Obj));

[gbracha, 2014/01/11 01:53:30]

Again, the inverse holds as well.

+
+  
+  // Function - argument type.
+  TypeMirror NumPredRef = reflectType(NumberPredicate).referent;
+  TypeMirror IntPredRef = reflectType(IntegerPredicate).referent;
+  TypeMirror DubPredRef = reflectType(DoublePredicate).referent;
+
+  Expect.isTrue(Func.isAssignableTo(Func));
+  Expect.isTrue(NumPredRef.isAssignableTo(NumPredRef));
+  Expect.isTrue(IntPredRef.isAssignableTo(IntPredRef));
+  Expect.isTrue(DubPredRef.isAssignableTo(DubPredRef));
+
+  Expect.isTrue(NumPredRef.isAssignableTo(Func));
+  Expect.isTrue(NumPredRef.isAssignableTo(IntPredRef));
+  Expect.isTrue(NumPredRef.isAssignableTo(DubPredRef));
+
+  Expect.isTrue(IntPredRef.isAssignableTo(Func));
+  Expect.isTrue(IntPredRef.isAssignableTo(NumPredRef));
+  Expect.isFalse(IntPredRef.isAssignableTo(DubPredRef));
+
+  Expect.isTrue(DubPredRef.isAssignableTo(Func));
+  Expect.isTrue(DubPredRef.isAssignableTo(NumPredRef));
+  Expect.isFalse(DubPredRef.isAssignableTo(IntPredRef));
+
+  Expect.isTrue(Func.isAssignableTo(Obj));
+  Expect.isTrue(NumPredRef.isAssignableTo(Obj));
+  Expect.isTrue(IntPredRef.isAssignableTo(Obj));
+  Expect.isTrue(DubPredRef.isAssignableTo(Obj));
+
+
+  // Function - return type.
+  TypeMirror NumGenRef = reflectType(NumberGenerator).referent;
+  TypeMirror IntGenRef = reflectType(IntegerGenerator).referent;
+  TypeMirror DubGenRef = reflectType(DoubleGenerator).referent;
+
+  Expect.isTrue(NumGenRef.isAssignableTo(NumGenRef));
+  Expect.isTrue(IntGenRef.isAssignableTo(IntGenRef));
+  Expect.isTrue(DubGenRef.isAssignableTo(DubGenRef));
+
+  Expect.isTrue(NumGenRef.isAssignableTo(Func));
+  Expect.isTrue(NumGenRef.isAssignableTo(IntGenRef));
+  Expect.isTrue(NumGenRef.isAssignableTo(DubGenRef));
+
+  Expect.isTrue(IntGenRef.isAssignableTo(Func));
+  Expect.isTrue(IntGenRef.isAssignableTo(NumGenRef));
+  Expect.isFalse(IntGenRef.isAssignableTo(DubGenRef));
+
+  Expect.isTrue(DubGenRef.isAssignableTo(Func));
+  Expect.isTrue(DubGenRef.isAssignableTo(NumGenRef));
+  Expect.isFalse(DubGenRef.isAssignableTo(IntGenRef));
+
+  Expect.isTrue(Func.isAssignableTo(Obj));
+  Expect.isTrue(NumGenRef.isAssignableTo(Obj));
+  Expect.isTrue(IntGenRef.isAssignableTo(Obj));
+  Expect.isTrue(DubGenRef.isAssignableTo(Obj));
+
+
+  // Function typedef / function.
+  Expect.isTrue(NumPred.isAssignableTo(NumPredRef));
+  Expect.isTrue(IntPred.isAssignableTo(IntPredRef));
+  Expect.isTrue(DubPred.isAssignableTo(DubPredRef));
+  Expect.isTrue(NumPredRef.isAssignableTo(NumPred));
+  Expect.isTrue(IntPredRef.isAssignableTo(IntPred));
+  Expect.isTrue(DubPredRef.isAssignableTo(DubPred));
+
+
+  // Function typedef / function.
+  Expect.isTrue(NumGen.isAssignableTo(NumGenRef));
+  Expect.isTrue(IntGen.isAssignableTo(IntGenRef));
+  Expect.isTrue(DubGen.isAssignableTo(DubGenRef));
+  Expect.isTrue(NumGenRef.isAssignableTo(NumGen));
+  Expect.isTrue(IntGenRef.isAssignableTo(IntGen));
+  Expect.isTrue(DubGenRef.isAssignableTo(DubGen));
+
+
+  // Type variable.
+  TypeMirror TFromA = reflectClass(A).typeVariables.single;
+  TypeMirror TFromB = reflectClass(B).typeVariables.single;
+  TypeMirror TFromC = reflectClass(C).typeVariables.single;
+
+  Expect.isTrue(TFromA.isAssignableTo(TFromA));
+  Expect.isTrue(TFromB.isAssignableTo(TFromB));
+  Expect.isTrue(TFromC.isAssignableTo(TFromC));
+
+  Expect.isFalse(TFromA.isAssignableTo(TFromB));
+  Expect.isFalse(TFromA.isAssignableTo(TFromC));
+  Expect.isFalse(TFromB.isAssignableTo(TFromA));
+  Expect.isFalse(TFromB.isAssignableTo(TFromC));
+  Expect.isFalse(TFromC.isAssignableTo(TFromA));
+  Expect.isFalse(TFromC.isAssignableTo(TFromB));
+  
+  Expect.isTrue(TFromC.isAssignableTo(reflectType(num)));
+  Expect.isTrue(reflectType(num).isAssignableTo(TFromC));
+
+
+  // dynamic & void.
+  TypeMirror Dynamic = currentMirrorSystem().dynamicType;
+  Expect.isTrue(Obj.isAssignableTo(Dynamic));
+  Expect.isTrue(Super.isAssignableTo(Dynamic));
+  Expect.isTrue(Sub1.isAssignableTo(Dynamic));
+  Expect.isTrue(Sub2.isAssignableTo(Dynamic));
+  Expect.isTrue(NumPred.isAssignableTo(Dynamic));
+  Expect.isTrue(IntPred.isAssignableTo(Dynamic));
+  Expect.isTrue(DubPred.isAssignableTo(Dynamic));
+  Expect.isTrue(NumPredRef.isAssignableTo(Dynamic));
+  Expect.isTrue(IntPredRef.isAssignableTo(Dynamic));
+  Expect.isTrue(DubPredRef.isAssignableTo(Dynamic));
+  Expect.isTrue(NumGen.isAssignableTo(Dynamic));
+  Expect.isTrue(IntGen.isAssignableTo(Dynamic));
+  Expect.isTrue(DubGen.isAssignableTo(Dynamic));
+  Expect.isTrue(NumGenRef.isAssignableTo(Dynamic));
+  Expect.isTrue(IntGenRef.isAssignableTo(Dynamic));
+  Expect.isTrue(DubGenRef.isAssignableTo(Dynamic));
+  Expect.isTrue(TFromA.isAssignableTo(Dynamic));
+  Expect.isTrue(TFromB.isAssignableTo(Dynamic));
+  Expect.isTrue(TFromC.isAssignableTo(Dynamic));
+  Expect.isTrue(Dynamic.isAssignableTo(Obj));
+  Expect.isTrue(Dynamic.isAssignableTo(Super));
+  Expect.isTrue(Dynamic.isAssignableTo(Sub1));
+  Expect.isTrue(Dynamic.isAssignableTo(Sub2));
+  Expect.isTrue(Dynamic.isAssignableTo(NumPred));
+  Expect.isTrue(Dynamic.isAssignableTo(IntPred));
+  Expect.isTrue(Dynamic.isAssignableTo(DubPred));
+  Expect.isTrue(Dynamic.isAssignableTo(NumPredRef));
+  Expect.isTrue(Dynamic.isAssignableTo(IntPredRef));
+  Expect.isTrue(Dynamic.isAssignableTo(DubPredRef));
+  Expect.isTrue(Dynamic.isAssignableTo(NumGen));
+  Expect.isTrue(Dynamic.isAssignableTo(IntGen));
+  Expect.isTrue(Dynamic.isAssignableTo(DubGen));
+  Expect.isTrue(Dynamic.isAssignableTo(NumGenRef));
+  Expect.isTrue(Dynamic.isAssignableTo(IntGenRef));
+  Expect.isTrue(Dynamic.isAssignableTo(DubGenRef));
+  Expect.isTrue(Dynamic.isAssignableTo(TFromA));
+  Expect.isTrue(Dynamic.isAssignableTo(TFromB));
+  Expect.isTrue(Dynamic.isAssignableTo(TFromC));
+
+  TypeMirror Void = currentMirrorSystem().voidType;

[gbracha, 2014/01/11 01:53:30]

Void vs. Void?

Also there are some special cases around functions that return void.

+  Expect.isFalse(Obj.isAssignableTo(Void));
+  Expect.isFalse(Super.isAssignableTo(Void));
+  Expect.isFalse(Sub1.isAssignableTo(Void));
+  Expect.isFalse(Sub2.isAssignableTo(Void));
+  Expect.isFalse(NumPred.isAssignableTo(Void));
+  Expect.isFalse(IntPred.isAssignableTo(Void));
+  Expect.isFalse(DubPred.isAssignableTo(Void));
+  Expect.isFalse(NumPredRef.isAssignableTo(Void));
+  Expect.isFalse(IntPredRef.isAssignableTo(Void));
+  Expect.isFalse(DubPredRef.isAssignableTo(Void));
+  Expect.isFalse(NumGen.isAssignableTo(Void));
+  Expect.isFalse(IntGen.isAssignableTo(Void));
+  Expect.isFalse(DubGen.isAssignableTo(Void));
+  Expect.isFalse(NumGenRef.isAssignableTo(Void));
+  Expect.isFalse(IntGenRef.isAssignableTo(Void));
+  Expect.isFalse(DubGenRef.isAssignableTo(Void));
+  Expect.isFalse(TFromA.isAssignableTo(Void));
+  Expect.isFalse(TFromB.isAssignableTo(Void));
+  Expect.isFalse(TFromC.isAssignableTo(Void));
+  Expect.isFalse(Void.isAssignableTo(Obj));
+  Expect.isFalse(Void.isAssignableTo(Super));
+  Expect.isFalse(Void.isAssignableTo(Sub1));
+  Expect.isFalse(Void.isAssignableTo(Sub2));
+  Expect.isFalse(Void.isAssignableTo(NumPred));
+  Expect.isFalse(Void.isAssignableTo(IntPred));
+  Expect.isFalse(Void.isAssignableTo(DubPred));
+  Expect.isFalse(Void.isAssignableTo(NumPredRef));
+  Expect.isFalse(Void.isAssignableTo(IntPredRef));
+  Expect.isFalse(Void.isAssignableTo(DubPredRef));
+  Expect.isFalse(Void.isAssignableTo(NumGen));
+  Expect.isFalse(Void.isAssignableTo(IntGen));
+  Expect.isFalse(Void.isAssignableTo(DubGen));
+  Expect.isFalse(Void.isAssignableTo(NumGenRef));
+  Expect.isFalse(Void.isAssignableTo(IntGenRef));
+  Expect.isFalse(Void.isAssignableTo(DubGenRef));
+  Expect.isFalse(Void.isAssignableTo(TFromA));
+  Expect.isFalse(Void.isAssignableTo(TFromB));
+  Expect.isFalse(Void.isAssignableTo(TFromC));
+
+  Expect.isTrue(Dynamic.isAssignableTo(Void));
+  Expect.isTrue(Void.isAssignableTo(Dynamic));
+}