[Bug libstdc++/94702] New: std::unsequenced_policy should not be defined for C++17

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94702

            Bug ID: 94702
           Summary: std::unsequenced_policy should not be defined for
                    C++17
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
                CC: rodgertq at gcc dot gnu.org
  Target Milestone: ---

This should compile without error in C++17:

// { dg-options "-std=gnu++17" }
// { dg-do compile { target c++17_only } }
#define unsequenced_policy 1
#include <execution>

It fails because std::unsequenced_policy is defined unconditionally.