Commit 69b5607
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 86150f3 commit 69b5607
2 files changed
Lines changed: 3 additions & 7 deletions
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -111,7 +111,7 @@ struct CallLibuvFunction<ReqT, void(*)(ReqT*, Args...)> { | |||
| 111 | 111 | template <typename ReqT, typename T> | |
| 112 | 112 | struct MakeLibuvRequestCallback { | |
| 113 | 113 | static T For(ReqWrap<ReqT>* req_wrap, T v) { | |
| 114 | - static_assert(!is_callable<T>::value, | ||
| 114 | + static_assert(!is_callable<T>, | ||
| 115 | 115 | "MakeLibuvRequestCallback missed a callback"); | |
| 116 | 116 | return v; | |
| 117 | 117 | } | |
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -661,13 +661,9 @@ struct MallocedBuffer { | |||
| 661 | 661 | }; | |
| 662 | 662 | ||
| 663 | 663 | // Test whether some value can be called with (). | |
| 664 | - template <typename T, typename = void> | ||
| 665 | - struct is_callable : std::is_function<T> { }; | ||
| 666 | - | ||
| 667 | 664 | template <typename T> | |
| 668 | - struct is_callable<T, typename std::enable_if< | ||
| 669 | - std::is_same<decltype(void(&T::operator())), void>::value | ||
| 670 | - >::type> : std::true_type { }; | ||
| 665 | + concept is_callable = | ||
| 666 | + std::is_function<T>::value || requires { &T::operator(); }; | ||
| 671 | 667 | ||
| 672 | 668 | template <typename T, void (*function)(T*)> | |
| 673 | 669 | struct FunctionDeleter { | |
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