tests/language/why_not_promoted/nullable_method_call_error_test.dart

// Copyright (c) 2021, 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.

// This test contains a test case for each condition that can lead to the front
// end's `NullableMethodCallError`, for which we wish to report "why not
// promoted" context information.

class C {
  int? i;
  //   ^
  // [context 3] 'i' refers to a property so it couldn't be promoted.
  // [context 4] 'i' refers to a property so it couldn't be promoted.
  // [context 5] 'i' refers to a property so it couldn't be promoted.
  // [context 6] 'i' refers to a property so it couldn't be promoted.
  void Function()? f;
  //               ^
  // [context 7] 'f' refers to a property so it couldn't be promoted.
}

extension on int {
  get propertyOnNonNullInt => null;
  void methodOnNonNullInt() {}
}

extension on int? {
  get propertyOnNullableInt => null;
  void methodOnNullableInt() {}
}

property_get_of_variable(int? i, int? j) {
  if (i == null) return;
  i = j;
//^
// [context 1] Variable 'i' could be null due to an intervening write.
  i.isEven;
//^
// [analyzer] COMPILE_TIME_ERROR.UNCHECKED_USE_OF_NULLABLE_VALUE
//  ^
// [cfe 1] Property 'isEven' cannot be accessed on 'int?' because it is potentially null.
}

extension_property_get_of_variable(int? i, int? j) {
  if (i == null) return;
  i = j;
//^
// [context 2] Variable 'i' could be null due to an intervening write.
  i.propertyOnNullableInt;
  i.propertyOnNonNullInt;
//^
// [analyzer] COMPILE_TIME_ERROR.UNCHECKED_USE_OF_NULLABLE_VALUE
//  ^
// [cfe 2] Property 'propertyOnNonNullInt' cannot be accessed on 'int?' because it is potentially null.
}

property_get_of_expression(C c) {
  if (c.i == null) return;
  c.i.isEven;
//^^^
// [analyzer] COMPILE_TIME_ERROR.UNCHECKED_USE_OF_NULLABLE_VALUE
//    ^
// [cfe 3] Property 'isEven' cannot be accessed on 'int?' because it is potentially null.
}

extension_property_get_of_expression(C c) {
  if (c.i == null) return;
  c.i.propertyOnNullableInt;
  c.i.propertyOnNonNullInt;
//^^^
// [analyzer] COMPILE_TIME_ERROR.UNCHECKED_USE_OF_NULLABLE_VALUE
//    ^
// [cfe 4] Property 'propertyOnNonNullInt' cannot be accessed on 'int?' because it is potentially null.
}

method_invocation(C c) {
  if (c.i == null) return;
  c.i.abs();
//^^^
// [analyzer] COMPILE_TIME_ERROR.UNCHECKED_USE_OF_NULLABLE_VALUE
//    ^
// [cfe 5] Method 'abs' cannot be called on 'int?' because it is potentially null.
}

extension_method_invocation(C c) {
  if (c.i == null) return;
  c.i.methodOnNullableInt();
  c.i.methodOnNonNullInt();
//^^^
// [analyzer] COMPILE_TIME_ERROR.UNCHECKED_USE_OF_NULLABLE_VALUE
//    ^
// [cfe 6] Method 'methodOnNonNullInt' cannot be called on 'int?' because it is potentially null.
}

call_invocation(C c) {
  if (c.f == null) return;
  c.f.call();
//^^^
// [analyzer] COMPILE_TIME_ERROR.UNCHECKED_USE_OF_NULLABLE_VALUE
//    ^
// [cfe 7] Method 'call' cannot be called on 'void Function()?' because it is potentially null.
}