Why do we { dg-require-debug-mode "" } for tests not using it?

[François Dumont]

On 10/01/2017 18:46, Jonathan Wakely wrote:
> We have a number of tests like
> testsuite/21_strings/debug/self_move_assign_neg.cc which use:
>
> // { dg-require-debug-mode "" }
>
> But then they #include <debug/string> and test __gnu_debug::string
> which is always available (not just in Debug Mode).
>
> Is there some reason for this?
>
>
I can't see any. Maybe some historical directive, has ever std::string 
Debug mode been activated with _GLIBCXX_DEBUG macro ?

According ChangeLog it is this way since introduction of this test case 
back in 2012.

François