blob: 5131d250aaa03b29850ee7f21939cc11144bb8a6 [file] [log] [blame]
// Copyright (c) 2015, 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.
// Verify semantics of the ?. operator when it is used to invoke a method.
import "package:expect/expect.dart";
import "conditional_access_helper.dart" as h;
bad() {
Expect.fail('Should not be executed');
}
noMethod(e) => e is NoSuchMethodError;
class B {}
class C extends B {
f(callback()) => callback();
int g(int callback()) => callback();
static staticF(callback()) => callback();
static int staticG(int callback()) => callback();
}
C nullC() => null;
main() {
// Make sure the "none" test fails if method invocation using "?." is not
// implemented. This makes status files easier to maintain.
nullC()?.f(null);
// o?.m(...) is equivalent to ((x) => x == null ? null : x.m(...))(o).
Expect.equals(null, nullC()?.f(bad())); //# 01: ok
Expect.equals(1, new C()?.f(() => 1)); //# 02: ok
// C?.m(...) is equivalent to C.m(...).
Expect.equals(1, C?.staticF(() => 1)); //# 14: ok
Expect.equals(1, h.C?.staticF(() => 1)); //# 15: ok
// The static type of o?.m(...) is the same as the static type of
// o.m(...).
{ int i = nullC()?.g(bad()); Expect.equals(null, i); } //# 03: ok
{ int i = new C()?.g(() => 1); Expect.equals(1, i); } //# 04: ok
{ String s = nullC()?.g(bad()); Expect.equals(null, s); } //# 05: static type warning
{ String s = new C()?.g(() => null); Expect.equals(null, s); } //# 06: static type warning
{ int i = C?.staticG(() => 1); Expect.equals(1, i); } //# 16: ok
{ int i = h.C?.staticG(() => 1); Expect.equals(1, i); } //# 17: ok
{ String s = C?.staticG(() => null); Expect.equals(null, s); } //# 18: static type warning
{ String s = h.C?.staticG(() => null); Expect.equals(null, s); } //# 19: static type warning
// Let T be the static type of o and let y be a fresh variable of type T.
// Exactly the same static warnings that would be caused by y.m(...) are also
// generated in the case of o?.m(...).
{ B b = new C(); Expect.equals(1, b?.f(() => 1)); } //# 07: static type warning
{ int i = 1; Expect.equals(null, nullC()?.f(i)); } //# 08: static type warning
// '?.' can't be used to access toplevel functions in libraries imported via
// prefix.
h?.topLevelFunction(); //# 11: compile-time error
// Nor can it be used to access the toString method on the class Type.
Expect.throws(() => C?.toString(), noMethod); //# 12: static type warning
Expect.throws(() => h.C?.toString(), noMethod); //# 13: static type warning
}