[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 #2 from Iain Buclaw <ibuclaw at gdcproject.org> ---
(In reply to Kenji Hara from comment #1)
> > 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.

OK, so long as that is a guarantee, that should be fine.  I just bumped into it
when looking for other things that have been bugging me with the way some
things are mangled.

Could the __U be replaced with an @ ?  That is one way to assert it never gets
generated.

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