Fix `std::visit` for the zero variants case.
Summary:
The following code is broken:
```
std::visit([]{});
```
Reviewers: EricWF
Reviewed By: EricWF
Differential Revision: https://reviews.llvm.org/D33090
llvm-svn: 302773
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 215f55f526b9f1d146d02f0955a127d6fc0bb703
diff --git a/include/variant b/include/variant
index 2c53e41..ba15ed8 100644
--- a/include/variant
+++ b/include/variant
@@ -425,30 +425,21 @@
constexpr auto __fmatrix =
__make_fmatrix<_Visitor&&,
decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
- const size_t __indices[] = {__vs.index()...};
- return __at(__fmatrix, __indices)(_VSTD::forward<_Visitor>(__visitor),
- _VSTD::forward<_Vs>(__vs).__as_base()...);
+ return __at(__fmatrix, __vs.index()...)(
+ _VSTD::forward<_Visitor>(__visitor),
+ _VSTD::forward<_Vs>(__vs).__as_base()...);
}
private:
template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
- static constexpr const _Tp& __at_impl(const _Tp& __elem, const size_t*) {
- return __elem;
- }
+ static constexpr const _Tp& __at(const _Tp& __elem) { return __elem; }
- template <class _Tp, size_t _Np>
- inline _LIBCPP_INLINE_VISIBILITY
- static constexpr auto&& __at_impl(const array<_Tp, _Np>& __elems,
- const size_t* __index) {
- return __at_impl(__elems[*__index], __index + 1);
- }
-
- template <class _Tp, size_t _Np, size_t _Ip>
+ template <class _Tp, size_t _Np, typename... _Indices>
inline _LIBCPP_INLINE_VISIBILITY
static constexpr auto&& __at(const array<_Tp, _Np>& __elems,
- const size_t (&__indices)[_Ip]) {
- return __at_impl(__elems, begin(__indices));
+ size_t __index, _Indices... __indices) {
+ return __at(__elems[__index], __indices...);
}
template <class _Fp, class... _Fs>