On Mon, Jan 4, 2021 at 9:49 PM Edward Diener
<eldlistmailingz@xxxxxxxxxxxxxx> wrote:
>
> The code, called test_predicate.cpp, simplified from a much more
> elaborate implementation:
>
> template < typename T, T *d > class atmp { atmp() {} };
>
> template < typename T > struct ast
> {
> static T avar;
> static atmp<T,&avar> acst;
> };
>
> template < typename T > T ast<T>::avar;
> template < typename T > atmp<T,&ast<T>::avar> ast<T>::acst;
>
> int main()
> {
> return 0;
> }
>
> The command line compile flags for gcc-10.2:
>
> -fvisibility-inlines-hidden -Wno-unused-local-typedefs
> -ftrack-macro-expansion=0 -Wno-unused-variable
> -D_GLIBCXX_USE_CXX11_ABI=1 -Wa,-mbig-obj -m64 -mthreads -O0 -fno-inline
> -Wall -g -fvisibility=hidden -std=c++11 -c
>
> The result:
>
> test_predicate.cpp:10:47: error: conflicting declaration 'atmp<T, (&
> ast<T>::avar)> ast<T>::acst'
> 10 | template < typename T > atmp<T,&ast<T>::avar> ast<T>::acst;
> | ^~~~~~
> test_predicate.cpp:6:26: note: previous declaration as 'atmp<T, (&
> ast<T>::avar)> ast<T>::acst'
> 6 | static atmp<T,&avar> acst;
> | ^~~~
>
> The same source compiled with clang-11.0 and VC++14.2 succeeds with no
> error.
>
> Is this s bug in gcc ? If so, is there a known workaround ?
Hmm, I'm not a language lawyer, and the error message does not seem to
make sense, but what happens when you remove the offending line in
your real program?
