| Issue |
61472
|
| Summary |
[Clang] Clang cannot deduce the type of a wrapper function.
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
haoyang9804
|
Repro file: https://godbolt.org/z/MPT6qezjs
```C++
#include <iostream>
#include <concepts>
#include <type_traits>
template<typename Fp, typename... A>
concept AcanPasstoFp = requires(Fp f, A... as) {
f(as...);
};
template<typename R, typename Fp, typename... A>
requires AcanPasstoFp<Fp, A...>
using WrapperType = R(*)(Fp, A...);
template<typename R, typename Fp, typename... A>
void metaWrapper(WrapperType<R, Fp, A...> wrapper, Fp f, A... as) {
wrapper(f, as...);
}
template<typename R, typename... A, typename Fp = R(*)(A...)>
void wrapper1(Fp f, A... as) {
std::cout << "wrapper1 !!" << std::endl;
f(as...);
}
void f1(int x) {
std::cout << "f1" << std::endl;
}
int main() {
metaWrapper(wrapper1, f1, 1);
}
```
I thought Clang can easily deduce `R` of metaWrapper cause the return type of wrapper is obviously `void`. But it fails with the following error message:
```
<source>:29:3: error: no matching function for call to 'metaWrapper'
metaWrapper(wrapper1, f1, 1);
^~~~~~~~~~~
<source>:14:6: note: candidate template ignored: couldn't infer template argument 'R'
void metaWrapper(WrapperType<R, Fp, A...> wrapper, Fp f, A... as) {
^
1 error generated.
```
Since I am new to generic programming with C++, I cannot tell if it's my fault or Clang's problem. Could anyone explain? Thanks
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