LanguageFeatures/Set-literals/type_inference_A01_t03.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 In a setOrMapLiteral collection, the inferred type of an element
/// is a set element type T, a pair of a key type K and a value type V, or both.
/// It is computed relative to a context type P:
///
/// If collection is unambiguously a set literal, then P is Set<Pe> where Pe is
/// determined by downwards inference, and may be ? if downwards inference does
/// not constrain it.
///
/// @description Checks that if collection is unambiguously a set literal, then P
/// is Set<Pe> where Pe is determined by downwards inference and may be ?
/// @author sgrekhov@unipro.ru

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

void test1<X extends num>(X x, X y) {
  var s1 = {x, y};
  var s2 = <X> {};
  Expect.isTrue(s1 is Set<int>);
  Expect.isTrue(s2 is Set<num>);
  Expect.runtimeIsType<Set<int>>(s1);
  Expect.runtimeIsType<Set<num>>(s2);
}

void test2<X extends num>(X x, X y) {
  var s1 = {x, y};
  var s2 = <X> {};
  Expect.isTrue(s1 is Set<double>);
  Expect.isTrue(s2 is Set<num>);
  Expect.runtimeIsType<Set<double>>(s1);
  Expect.runtimeIsType<Set<num>>(s2);
}

void test3<X extends num>(X x, X y) {
  var s1 = {x, y};
  var s2 = <X> {};
  Expect.isTrue(s1 is Set<num>);
  Expect.isTrue(s2 is Set<num>);
  Expect.runtimeIsType<Set<num>>(s1);
  Expect.runtimeIsType<Set<num>>(s2);
}

main() {
  test1(3, 1);
  test2(3.14, 2.718);
  test3(3, 2.718);
}