| /* |
| * 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. |
| */ |
| /** |
| * @assertion Let d be the declaration of a variable v. If d is a local or |
| * instance variable, then the invocation of the implicit getter of v |
| * evaluates to the value stored in v. |
| * If d is a static or library variable then the implicit getter method of v |
| * executes as follows: |
| * - Non-constant variable declaration with initializer. If d is of one of the |
| * forms var v = e; , T v = e; , final v = e; , final T v = e; , static |
| * v = e; , static T v = e; , static final v = e; or static final T v = e; |
| * and no value has yet been stored into v then the initializer expression |
| * e is evaluated. If, during the evaluation of e, the getter for v is |
| * invoked, a CyclicInitializationError is thrown. If the evaluation |
| * succeeded yielding an object o, let r = o, otherwise let r = null. In |
| * any case, r is stored into v. The result of executing the getter is r. |
| * - Constant variable declaration. If d is of one of the forms const v = e; , |
| * const T v = e; , static const v = e; or static const T v = e; the result |
| * of the getter is the value of the compile time constant e. Note that a |
| * compile time constant cannot depend on itself, so no cyclic references |
| * can occur. Otherwise |
| * - Variable declaration without initializer. The result of executing the |
| * getter method is the value stored in v. |
| * |
| * @note The language specification says 'If, during the evaluation of [e] |
| * (which is the initializing expression for [v]), the getter for [v] is invoked, |
| * a [CyclicInitializationError] is thrown', but this is overridden by the |
| * following text in the nnbd feature specification: 'If a variable or field is |
| * read from during the process of evaluating its own initializer expression, |
| * and no write to the variable has occurred, the read is treated as a first |
| * read and the initializer expression is evaluated again.' |
| * So CyclicInitializationErrors are gone here when null safety is enabled. |
| * In the test, [f] returns [null] (typed as [dynamic]), and the evaluation of |
| * the initializing expression for [sVar] as well as [sFinal] discards the |
| * function literal (() => sVar respectively () => sFinal) without ever |
| * executing it. So we do not have a situation where the getter for |
| * [sVar]/[sFinal] is invoked during the evaluation of its initializing |
| * expression, and both variables just get initialized to the value [null]. No |
| * recursion and no errors. |
| * |
| * @description Checks that [CyclicInitializationError] is not thrown with null |
| * safety turned on. |
| * |
| * @author sgrekhov@unipro.ru |
| */ |
| f(func) {} |
| |
| class C { |
| static var sVar = f(() => sVar); |
| static final sFinal = f(() => sFinal); |
| } |
| |
| main() { |
| C? c; |
| } |