LanguageFeatures/Spread-collections/Syntax_A02_t09.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 The grammar changes for map and set are a little more complex
/// because of the potential ambiguity of collections containing only spreads.
/// The changed and new rules are:
///
///    setOrMapLiteral:
///    mapLiteral |
///    setLiteral |
///    mapOrSetLiteral
///    ;
///
///    mapLiteral:
///    const? typeArguments? '{' mapLiteralEntryList? '}'
///    ;
///
///    mapLiteralEntryList:
///    mapLiteralEntry ( ',' mapLiteralEntry )* ','?
///    ;
///
///    mapLiteralEntry:
///    expression ':' expression |
///    spread
///    ;
///
///    setLiteral:
///    'const'? typeArguments? '{' spreadableList '}' ;
///
///    mapOrSetLiteral:
///    'const'?  '{' spread (',' spread)* '}' ;
///
/// @description Checks that exception is thrown if spreadable element is not
/// set for spreadable map.
/// @author iarkh@unipro.ru


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

Map map1 = {1: 1, 2: 4, 3: 6};
late Map map2;

main() {
  Map a;

  Expect.throws(() => a = {...map2});
  Expect.throws(() => a = {...map1, ...map2});
  Expect.throws(() => a = {...map2, ...map1});
  Expect.throws(() => a = {...map2, 10: 2});
  Expect.throws(() => a = {...map2, 11: 10});
  Expect.throws(() => a = {10: 128, ...map2});
}