ObjCAutoreleaseWriteChecker.cpp

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//===- ObjCAutoreleaseWriteChecker.cpp ---------------------------*- C++ -*-==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines ObjCAutoreleaseWriteChecker which warns against writes
// into autoreleased out parameters which cause crashes.
// An example of a problematic write is a write to @c error in the example
// below:
//
// - (BOOL) mymethod:(NSError *__autoreleasing *)error list:(NSArray*) list {
//     [list enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
//       NSString *myString = obj;
//       if ([myString isEqualToString:@"error"] && error)
//         *error = [NSError errorWithDomain:@"MyDomain" code:-1];
//     }];
//     return false;
// }
//
// Such code will crash on read from `*error` due to the autorelease pool
// in `enumerateObjectsUsingBlock` implementation freeing the error object
// on exit from the function.
//