On 26 March 2018 at 14:10, Jonathan Wakely wrote:
> This makes it possible to use our std::variant with Clang, as well as
> some minor tweaks to avoid ADL (so the compiler doesn't waste time
> looking in associated namespaces) and adjust whitespace.
>
> * include/std/variant (__get): Qualify calls to avoid ADL.
> (__select_index): Adjust whitespace.
> (variant): Add using-declaration to workaround Clang bug.
>
> Tested powerpc64le-linux, committed to trunk.. I'll backport to
> gcc-7-branch too.
The Clang bug means that __get is ambiguous (because it thinks the
friend declaration is a separate overload) so we also need this
change.
Tested powerpc64le-linux, committed to trunk.
commit c09f881053d98370306098b7bad5bb829255379c
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Apr 5 14:03:13 2018 +0100
Add another workaround to std::variant for Clang bug 31852
* include/std/variant (_VARIANT_RELATION_FUNCTION_TEMPLATE): Qualify
__get calls to avoid ADL and avoid ambiguity due to Clang bug.
diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant
index 028d3064272..48bec528406 100644
--- a/libstdc++-v3/include/std/variant
+++ b/libstdc++-v3/include/std/variant
@@ -272,8 +272,8 @@ namespace __variant
constexpr bool \
__erased_##__NAME(const _Variant& __lhs, const _Variant& __rhs) \
{ \
- return __get<_Np>(std::forward<_Variant>(__lhs)) \
- __OP __get<_Np>(std::forward<_Variant>(__rhs)); \
+ return __variant::__get<_Np>(std::forward<_Variant>(__lhs)) \
+ __OP __variant::__get<_Np>(std::forward<_Variant>(__rhs)); \
}
_VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
