pkg/kernel/test/flatten_test.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.

import "package:expect/expect.dart" show Expect;

import 'package:kernel/ast.dart';
import 'package:kernel/class_hierarchy.dart';
import 'package:kernel/testing/type_parser_environment.dart';
import 'package:kernel/type_environment.dart';

const Set<Test> data = {
  const Test('Null', 'Null'),
  const Test('Never?', 'Never?'),
  const Test('void', 'void'),
  const Test('dynamic', 'dynamic'),
  const Test('bool', 'bool'),
  const Test('bool?', 'bool?'),
  const Test('List<bool>', 'List<bool>'),
  const Test('List<bool>?', 'List<bool>?'),
  const Test('FutureOr<bool>', 'bool'),
  const Test('FutureOr<bool>?', 'bool?'),
  const Test('FutureOr<bool?>?', 'bool?'),
  const Test('FutureOr<Null>', 'Null'),
  const Test('FutureOr<Null>?', 'Null'),
  const Test('Future<bool>', 'bool'),
  const Test('Future<bool>?', 'bool?'),
  const Test('Future<bool?>', 'bool?'),
  const Test('() ->? bool?', '() ->? bool?'),
  const Test('() -> bool?', '() -> bool?'),
  const Test('() ->? bool', '() ->? bool'),
  const Test('() -> bool', '() -> bool'),
  const Test('T', 'T', 'T'),
  const Test('T?', 'T?', 'T'),
  const Test('T', 'T', 'T extends bool'),
  const Test('T?', 'T?', 'T extends bool'),
  const Test('T', 'bool', 'T extends FutureOr<bool>'),
  const Test('T?', 'bool?', 'T extends FutureOr<bool>'),
  const Test('T', 'bool', 'T extends Future<bool>'),
  const Test('T?', 'bool?', 'T extends Future<bool>'),
  const Test('T & bool', 'T', 'T'),
  const Test('T & bool?', 'T', 'T'),
};

class Test {
  final String input;
  final String output;
  final String? typeParameters;

  const new(this.input, this.output, [this.typeParameters]);
}

void main() {
  Env env = new Env('');
  ClassHierarchy classHierarchy = new ClassHierarchy(
    env.component,
    env.coreTypes,
  );
  TypeEnvironment typeEnvironment = new TypeEnvironment(
    env.coreTypes,
    classHierarchy,
  );
  data.forEach((Test test) {
    env.withTypeParameters(test.typeParameters, (
      List<TypeParameter> typeParameterNodes,
    ) {
      String input = test.input;
      String output = test.output;
      DartType inputType = env.parseType(input);
      DartType expectedOutputType = env.parseType(output);
      DartType actualOutputType = typeEnvironment.flatten(inputType);
      print(
        'flatten($inputType) '
        '${test.typeParameters != null ? 'with ${test.typeParameters} ' : ''}'
        '= $actualOutputType, expected $expectedOutputType',
      );
      Expect.equals(
        expectedOutputType,
        actualOutputType,
        "Unexpected flatten of $inputType ('$input'):\n"
        "Expected: ${expectedOutputType} ('$output')\n"
        "Actual: ${actualOutputType}",
      );
    });
  });
}