tests/language/anonymous_methods/block/promotion_test.dart

// Copyright (c) 2026, 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.

// SharedOptions=--enable-experiment=anonymous-methods

import '../../static_type_helper.dart';

final String receiver = '';
final String? maybeReceiver = receiver;

void main() {
  // Promotion in an anonymous method body succeeds.
  {
    Object o = 1;

    receiver.{
      o as int;
    };

    o.expectStaticType<Exactly<int>>;
  }

  // Ditto, cascaded.
  {
    Object o = 1;

    receiver..{
      o as int;
    };

    o.expectStaticType<Exactly<int>>;
  }

  // Promotion in a null-aware anonymous method body does not survive.
  {
    Object o = 1;

    maybeReceiver?.{
      o as int;
    };

    o.expectStaticType<Exactly<Object>>;
  }

  // Ditto, cascaded.
  {
    Object o = 1;

    maybeReceiver?..{
      o as int;
    };

    o.expectStaticType<Exactly<Object>>;
  }

  // Assignment in an anonymous method body does not make the variable
  // non-promotable, null-aware/cascaded or not.
  {
    Object o = 1;

    receiver.{
      o = true;
      o = 2;
    };

    receiver..{
      o = true;
      o = 2;
    };

    maybeReceiver?.{
      o = true;
      o = 2;
    };

    maybeReceiver?..{
      o = true;
      o = 2;
    };

    if (o is int) {
      o.expectStaticType<Exactly<int>>;
    }
  }

  // Propagate promotion from one anonymous method to the next.
  {
    Object o1 = 1, o3 = 3;
    Object? o2 = 2 as dynamic, o4 = 4 as dynamic; // Cast to avoid promotion.

    receiver.{
      o1 as int;
    }.{
      o1.isEven;
    };

    maybeReceiver?.{
      return o2 as int?;
    }?.{
      o2.expectStaticType<Exactly<int?>>;
    };

    receiver.{
      o3 as num;
    }.{
      o3 as int;
    }.{
      o3.isEven;
    };

    maybeReceiver?.{
      return o4 as num?;
    }?.{
      return o4 as int?;
    }?.{
      o4.expectStaticType<Exactly<int?>>;
    };
  }

  // Ditto, cascaded.
  {
    Object o1 = 1, o2 = 2, o3 = 3, o4 = 4;

    receiver
      ..{ o1 as int; }
      ..{ o1.isEven; };
    maybeReceiver
      ?..{ o2 as int; }
      ..{ o2.isEven; };
    receiver
      ..{ o3 as num; }
      ..{ o3 as int; }
      ..{ o3.isEven; };
    maybeReceiver
      ?..{ o4 as num; }
      ..{ o4 as int; }
      ..{ o4.isEven; };
  }
}