[Bug libstdc++/101965] check in charconv is vacuously true

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101965

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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   Target Milestone|---                         |10.4
           Severity|normal                      |trivial

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed on trunk, but I plan to backport it.