LanguageFeatures/Spread-collections/TypeInference_A05_t04.dart

// Copyright (c) 2019, 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.

/// @assertion From the Unified collections Spec:
/// We require that at least one component unambiguously determine the literal
/// form, otherwise it is a compile-time error. So, given:
///    dynamic x = <int, int>{};
///    Iterable l = [];
///    Map m = {};
///    Then:
///    {...x}       // Static error, because it is ambiguous.
///    {...x, ...l} // Statically a set, runtime error when spreading x.
///    {...x, ...m} // Statically a map, no runtime error.
///    {...l, ...m} // Static error, because it must be both a set and a map.
/// @description Checks that if one of the spreadable element is [Iterable],
/// result is statically [Set]
/// @author iarkh@unipro.ru

import "../../Utils/expect.dart";

main() {
  dynamic map = <int, int>{};
  dynamic set = <int>{};
  Iterable l = [];

  Set res;
  Expect.throws(() =>  res = {...?l, ...map});
//                            ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                                ^
// [cfe] Operand of null-aware operation '...?' has type 'Iterable<dynamic>' which excludes null.
  Expect.throws(() =>  res = {...map, ...?l});
//                                    ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                                        ^
// [cfe] Operand of null-aware operation '...?' has type 'Iterable<dynamic>' which excludes null.

  Expect.throws(() =>  res = {...l, ...?map});
  Expect.throws(() =>  res = {...?map, ...l});

  Expect.throws(() =>  res = {...?l, ...?map});
//                            ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                                ^
// [cfe] Operand of null-aware operation '...?' has type 'Iterable<dynamic>' which excludes null.
  Expect.throws(() =>  res = {...?map, ...?l});
//                                     ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                                         ^
// [cfe] Operand of null-aware operation '...?' has type 'Iterable<dynamic>' which excludes null.

  Expect.isTrue({...set, ...?l} is Set);
//                       ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                           ^
// [cfe] Operand of null-aware operation '...?' has type 'Iterable<dynamic>' which excludes null.
  Expect.isTrue({...?l, ...set} is Set);
//               ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                   ^
// [cfe] Operand of null-aware operation '...?' has type 'Iterable<dynamic>' which excludes null.

  Expect.isTrue({...?set, ...l} is Set);
  Expect.isTrue({...l, ...?set} is Set);

  Expect.isTrue({...?set, ...?l} is Set);
//                        ^^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//                            ^
// [cfe] Operand of null-aware operation '...?' has type 'Iterable<dynamic>' which excludes null.
}