Assigning a non-nil value to a weak SWIFT_SHARED_REFERENCE variable crashes at runtime #83080
Description
Description
No response
Reproduction
struct SharedRef {
static inline SharedRef*_Nonnull makeSharedRef() SWIFT_RETURNS_RETAINED {
return new SharedRef();
}
private:
SharedRef() : _refCount(1) {}
SharedRef(const SharedRef& other) = delete;
SharedRef& operator=(const SharedRef& other) = delete;
friend inline void retainSharedRef(SharedRef*_Nonnull x) {
x->_refCount += 1;
}
friend inline void releaseSharedRef(SharedRef*_Nonnull x) {
x->_refCount -= 1;
if (x->_refCount == 0) {
delete x;
}
}
int _refCount;
} SWIFT_SHARED_REFERENCE(retainSharedRef, releaseSharedRef);func foo() {
weak var x: SharedRef?
let y: SharedRef = SharedRef.makeSharedRef()
x = y // runtime crash!
}
foo()Stack dump
(lldb) bt
* thread #1, stop reason = EXC_BAD_ACCESS (code=1, address=0x20)
frame #0: 0x00000001921143c8 libswiftCore.dylib`swift::WeakReference::unknownAssign(void*) + 72
frame #1: 0x0000000192114370 libswiftCore.dylib`swift_unknownObjectWeakAssign + 24
* frame #2: 0x0000000100000ca4 WeakFRTCrash`foo() at main.swift:16:7
frame #3: 0x0000000100000bbc WeakFRTCrash`main at main.swift:19:1
frame #4: 0x0000000180532b4c dyld`start + 6000
Expected behavior
I expected the runtime crash would not occur. (Using weak or unowned with SWIFT_SHARED_REFERENCE should probably be a compiler error, since I don't think there's a way for the Swift runtime to weakly hold C++ reference types, so this code should probably not compile at all.)
Environment
swift-driver version: 1.120.5 Apple Swift version 6.1 (swiftlang-6.1.0.110.21 clang-1700.0.13.3)
Target: arm64-apple-macosx15.0
Additional information
rdar://124040825