[cxx-interop] An std::optional<bool>'s .value is always false in Release mode #84848
Description
Description
When passing an std::optional<bool> to Swift, it automatically conforms to the CxxOptional protocol. This protocol has a hasValue and a value properties:
While hasValue seems to always hold the correct value (true), the value property only properly works in Debug mode. Once you build the app in Release mode, it always holds false instead of true for my boolean.
I confirmed this by
- Logging the boolean in C++ first, then in Swift, and it in C++ it was
truewhereas in Swift it wasfalse - Creating a helper function in C++ to actually get the value, then calling it from Swift - in which case it returned
trueagain and works
Reproduction
Swift:
func myMethod(opt: helpers.specialized_std_optional_bool) {
let wrongValue = opt.value
let actualValue: Bool? = opt.hasValue ? helpers.get_std_optional_bool(opt) : nil
}C++:
using specialized_std_optional_bool = std::optional<bool>;
bool get_std_optional_bool(std::optional<bool> opt) {
return opt.value();
}Expected behavior
I expect the .value property to always hold a correct value
Environment
swift-driver version: 1.127.14.1 Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)
Target: arm64-apple-macosx26.0
Additional information
Original bug reported in mrousavy/nitro#876