Commit c9cde35
src: simplify is_callable by making it a concept
Using a C++20 `concept` here makes `is_callable` much simpler
than relying on SFINAE. It is equivalent for function types,
`std::function`, lambdas, and classes with `operator()`,
regardless of argument or return types.
PR-URL: #58169
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>1 parent 892b425 commit c9cde35
2 files changed
Lines changed: 3 additions & 7 deletions
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -106,7 +106,7 @@ struct CallLibuvFunction<ReqT, void(*)(ReqT*, Args...)> { | |||
| 106 | 106 | template <typename ReqT, typename T> | |
| 107 | 107 | struct MakeLibuvRequestCallback { | |
| 108 | 108 | static T For(ReqWrap<ReqT>* req_wrap, T v) { | |
| 109 | - static_assert(!is_callable<T>::value, | ||
| 109 | + static_assert(!is_callable<T>, | ||
| 110 | 110 | "MakeLibuvRequestCallback missed a callback"); | |
| 111 | 111 | return v; | |
| 112 | 112 | } | |
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -660,13 +660,9 @@ struct MallocedBuffer { | |||
| 660 | 660 | }; | |
| 661 | 661 | ||
| 662 | 662 | // Test whether some value can be called with (). | |
| 663 | - template <typename T, typename = void> | ||
| 664 | - struct is_callable : std::is_function<T> { }; | ||
| 665 | - | ||
| 666 | 663 | template <typename T> | |
| 667 | - struct is_callable<T, typename std::enable_if< | ||
| 668 | - std::is_same<decltype(void(&T::operator())), void>::value | ||
| 669 | - >::type> : std::true_type { }; | ||
| 664 | + concept is_callable = | ||
| 665 | + std::is_function<T>::value || requires { &T::operator(); }; | ||
| 670 | 666 | ||
| 671 | 667 | template <typename T, void (*function)(T*)> | |
| 672 | 668 | struct FunctionDeleter { | |
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