`<functional>`: `move_only_function` behaves differently when constructed with null function pointer in slightly different ways
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question
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- C++
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Description
The following program:
#include <functional>
#include <print>
int main() {
std::move_only_function<int(int)> fn1(static_cast<int(*)(int)>(nullptr));
std::move_only_function<int(int)> fn2(std::in_place_type<int(*)(int)>, nullptr);
std::print("fn1: {}, fn2: {}", static_cast<bool>(fn1), static_cast<bool>(fn2));
}
Prints:
fn1: false, fn2: true
This is what the Standard is apparently asking for.
Isn't this stupid?
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Research direction
Run the supplied C++ reproducer and compare the two std::move_only_function constructions described in the issue. No source file or test is named; determine from the Standard whether the differing states are intended, then document the expected outcome before proposing any change.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100