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// 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 does not appear on the LHS of an
// assignment.
import "package:expect/expect.dart";
import "conditional_access_helper.dart" as h;
class B {}
class C extends B {
int v;
C(this.v);
static int staticInt;
}
C nullC() => null;
main() {
// Make sure the "none" test fails if property access using "?." is not
// implemented. This makes status files easier to maintain.
nullC()?.v;
// e1?.id is equivalent to ((x) => x == null ? null : x.id)(e1).
Expect.equals(null, nullC()?.v);
Expect.equals(1, new C(1)?.v);
// C?.id is equivalent to C.id.
{ C.staticInt = 1; Expect.equals(1, C?.staticInt); }
{ h.C.staticInt = 1; Expect.equals(1, h.C?.staticInt); }
// The static type of e1?.d is the static type of e1.id.
{ int i = new C(1)?.v; Expect.equals(1, i); }
{ String s = new C(null)?.v; Expect.equals(null, s); }
// ^^^^^^^^^^^^^^
// [analyzer] COMPILE_TIME_ERROR.INVALID_ASSIGNMENT
// ^
// [cfe] A value of type 'int' can't be assigned to a variable of type 'String'.
{ C.staticInt = 1; int i = C?.staticInt; Expect.equals(1, i); }
{ h.C.staticInt = 1; int i = h.C?.staticInt; Expect.equals(1, i); }
{ C.staticInt = null; String s = C?.staticInt; Expect.equals(null, s); }
// ^^^^^^^^^^^^
// [analyzer] COMPILE_TIME_ERROR.INVALID_ASSIGNMENT
// ^
// [cfe] A value of type 'int' can't be assigned to a variable of type 'String'.
{ h.C.staticInt = null; String s = h.C?.staticInt; Expect.equals(null, s); }
// ^^^^^^^^^^^^^^
// [analyzer] COMPILE_TIME_ERROR.INVALID_ASSIGNMENT
// ^
// [cfe] A value of type 'int' can't be assigned to a variable of type 'String'.
// Let T be the static type of e1 and let y be a fresh variable of type T.
// Exactly the same static warnings that would be caused by y.id are also
// generated in the case of e1?.id.
Expect.equals(null, nullC()?.bad);
// ^^^
// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_GETTER
// [cfe] The getter 'bad' isn't defined for the class 'C'.
{ B b = new C(1); Expect.equals(1, b?.v); }
// ^
// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_GETTER
// [cfe] The getter 'v' isn't defined for the class 'B'.
// '?.' cannot be used to access toplevel properties in libraries imported via
// prefix.
var x = h?.topLevelVar;
// ^
// [analyzer] COMPILE_TIME_ERROR.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT
// [cfe] A prefix can't be used with null-aware operators.
// Nor can it be used to access the hashCode getter on the class Type.
Expect.throwsNoSuchMethodError(() => C?.hashCode);
// ^^^^^^^^
// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_GETTER
// [cfe] Getter not found: 'hashCode'.
Expect.throwsNoSuchMethodError(() => h.C?.hashCode);
// ^^^^^^^^
// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_GETTER
// [cfe] Getter not found: 'hashCode'.
}