[gcc r12-4508] libstdc++: Change std::variant union member to empty struct
Jonathan Wakely
redi@gcc.gnu.org
Tue Oct 19 14:01:57 GMT 2021
https://gcc.gnu.org/g:5a8832b1659e311437d25b7ec8b078be27ae54b8
commit r12-4508-g5a8832b1659e311437d25b7ec8b078be27ae54b8
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Oct 19 11:53:27 2021 +0100
libstdc++: Change std::variant union member to empty struct
This more clearly expresses the intent (a completely unused, trivial
type) than using char. It's also consistent with the unions in
std::optional.
libstdc++-v3/ChangeLog:
* include/std/variant (_Uninitialized): Use an empty struct
for the unused union member, instead of char.
Diff:
---
libstdc++-v3/include/std/variant | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant
index d18365fde22..3da7dad1e82 100644
--- a/libstdc++-v3/include/std/variant
+++ b/libstdc++-v3/include/std/variant
@@ -293,8 +293,10 @@ namespace __variant
constexpr _Type&& _M_get() && noexcept
{ return std::move(_M_storage); }
+ struct _Empty_byte { };
+
union {
- char _M_nope;
+ _Empty_byte _M_empty;
_Type _M_storage;
};
#else
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