Fix PR31916 - std::visit rejects visitors accepting lvalue arguments
A static assertion was misfiring since it checked
is_callable<Visitor, decltype(__variant_alt<T>.value)>. However
the decltype expression doesn't capture the value category as
required. This patch applies extra braces to decltype to fix
that.
llvm-svn: 294612
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: a18ef6f1f9d2a32519192feedadb7814461db488
diff --git a/include/variant b/include/variant
index fb7cb2e..099e6c3 100644
--- a/include/variant
+++ b/include/variant
@@ -578,7 +578,7 @@
constexpr decltype(auto) operator()(_Alts&&... __alts) const {
__std_visit_exhaustive_visitor_check<
_Visitor,
- decltype(_VSTD::forward<_Alts>(__alts).__value)...>();
+ decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
return __invoke_constexpr(_VSTD::forward<_Visitor>(__visitor),
_VSTD::forward<_Alts>(__alts).__value...);
}