LanguageFeatures/Set-literals/type_inference_A06_t02.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 To infer the type of element:
/// ...
/// If element is a mapEntry ek: ev:
/// ...
/// If P is Map<Pk, Pv> then the inferred key type of element is the inferred
/// type of ek in context Pk and the inferred value type of element is the
/// inferred type of ev in context Pv.
///
/// @description Checks that if P is Map<Pk, Pv> then the inferred key type of
/// element is the inferred type of ek in context Pk and the inferred value type
/// of element is the inferred type of ev in context Pv.
///
/// See Issue 43139 evaluation: With null safety, doing 1 + x in a double context
/// will figure out that the only way int + something is going to be a double is
/// if the something is a double, so it will give x a context type of double.
/// Then double x = 1 + 1; will convert the latter 1 to a double literal, and the
/// result becomes a double. So, there is not compile error here with nnbd, and
/// it's a compile error without nnbd.
/// @Issue 43139
/// @author sgrekhov@unipro.ru

main() {
  Map<double, double> x1 = {1 + 1: 1.0};
  Map<double, double> x2 = {1.0: 1 + 1};
}