void store(T desired, memory_order order = memory_order::seq_cst) volatile noexcept;
void store(T desired, memory_order order = memory_order::seq_cst) noexcept;

Preconditions: The order argument is neither memory_order​::​consume, memory_order​::​acquire, nor memory_order​::​acq_rel.

The LWG side asked me to open an editorial post about this issue, even though I have already tried to report an issue on CWG, and the CWG side(cplusplus/CWG#398) has confirmed that this issue should be reported as an LWG issue. The original issue is:

#include <atomic>
int main(){
   std::atomic<int> v{0};
   auto invented_ordering = static_cast<std::memory_order>(1024);
   v.store(1,invented_ordering);
}

[enum.dcl.enum] p8 says:

It is possible to define an enumeration that has values not defined by any of its enumerators.

The invented_ordering does not violate the preconditions of the store, however, this is obviously problematic.