llvm-capstone/clang/test/SemaObjC/objc-precise-lifetime-unused-variable.m
Michael Wyman b682616d1f Clang unused-but-set-variable warnings should not apply to __attribute__((objc_precise_lifetime)) Objective-C pointers
The `objc_precise_lifetime` attribute is applied to Objective-C pointers to ensure the optimizer does not prematurely release an object under Automatic Reference Counting (ARC). It is a common enough pattern to assign values to these variables but not reference them otherwise, and annotating them with `__unused` is not really correct as they are being used to ensure an object's lifetime.

Differential Revision: https://reviews.llvm.org/D120372
2022-02-24 14:26:05 -08:00

23 lines
580 B
Objective-C

// RUN: %clang_cc1 -triple x86_64-apple-macos11 -fsyntax-only -fobjc-arc -fblocks -verify -Wunused-but-set-variable -Wno-objc-root-class %s
id getFoo(void);
void test() {
// no diagnostics for objects with precise lifetime semantics.
__attribute__((objc_precise_lifetime)) id x;
x = getFoo();
id x2; // expected-warning {{variable 'x2' set but not used}}
x2 = getFoo();
do {
__attribute__((objc_precise_lifetime)) id y;
y = getFoo();
id y2; // expected-warning {{variable 'y2' set but not used}}
y2 = getFoo();
} while(0);
x = ((void *)0);
}