clang accepts partial template specialization without base

[abellgithub]

This fails on gcc but works on clang. Note types of SYMS template arguments. I think clang is wrong here, but it could be me who's wrong ;)

#include <cstdint>
#include <type_traits>

template <int SYMS, typename T=void>
struct arithmetic_c;

template<uint32_t SYMS>
struct arithmetic_c<SYMS, typename std::enable_if<(SYMS > 16 && SYMS < 2048)>::type>
{
    arithmetic_c()
    {}
};

template<int SYMS>
struct arithmetic_c<SYMS, typename std::enable_if<(SYMS > 1 && SYMS <= 16)>::type >
{
    arithmetic_c()
    {}
};

int main()
{
    arithmetic_c<32> corrector;
    return 0;
}

Compiler Explorer

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Andrew Bell (abellgithub)

This fails on gcc but works on clang. Note types of `SYMS` template arguments. I think clang is wrong here, but it could be me who's wrong ;)

#include <cstdint>
#include <type_traits>

template <int SYMS, typename T=void>
struct arithmetic_c;

template<uint32_t SYMS>
struct arithmetic_c<SYMS, typename std::enable_if<(SYMS > 16 && SYMS < 2048)>::type>
{
    arithmetic_c()
    {}
};

template<int SYMS>
struct arithmetic_c<SYMS, typename std::enable_if<(SYMS > 1 && SYMS <= 16)>::type >
{
    arithmetic_c()
    {}
};

int main()
{
    arithmetic_c<32> corrector;
    return 0;
}

Compiler Explorer

[pinskia]

I think this is related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60679 and https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1647

[abellgithub]

Yes, seems exactly the issue. Please close if you like.

[pinskia]

Yes, seems exactly the issue. Please close if you like.

Well the defect report against the C++ standard is still open. I didn't look to see if there is a different LLVM bug open referencing that defect report.

[shafik]

gcc/edg agree and clang/MSVC agree: https://godbolt.org/z/c3j3EEn1x