Proposed resolution:

This wording is relative to N4830.

1. Add a new sub-clause at the end of Clause [depr] as indicated:

   D.?? Deprecated memory_order enumerators

   -?- The following enumerators are declared in addition to those specified in [atomics.order]:

   namespace std {
     enum class memory_order : unspecified {
       memory_order_relaxed = relaxed, memory_order_consume = consume, memory_order_acquire = acquire, 
       memory_order_release = release, memory_order_acq_rel = acq_rel, memory_order_seq_cst = seq_cst
     };
   }
   

[ 2019-10 Priority set to 4 after reflector discussion ]

P0439R0 renamed the std::memory_order enumerators when making it a scoped enumeration. The paper makes the old unscoped names available in the global namespace, but not within the scope of the enumeration.

For example:

std::memory_order::memory_order_consume is no longer well-formed but std::memory_order::consume and std::memory_order_consume are.

In order to prevent unnecessary breakage, we should re-add the memory_order_foo names to the enumeration.