[Issue 14592] [SPEC] Undocumented use of __U for mangling template constraints

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14592

--- Comment #1 from Kenji Hara <k.hara.pg at gmail.com> ---
> I've never come across it, so maybe it's just dead code in DMD.

__U is never used for any generated symbols, so it's not necessary to be
documented in the spec.

But in dmd front-end, it's actually used internally for a *temporary* instance
which used on evaluation of template constraint.

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