[Bug c++/71965] [6/7/8 regression] [concepts] Substitution error *after* failure to satisfy an earlier constraint

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71965

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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             Status|NEW                         |ASSIGNED
                 CC|                            |aoliva at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |aoliva at gcc dot gnu.org

--- Comment #7 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Created attachment 43690
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43690&action=edit
candidate patch

Here's a work-around I'm testing.  It doesn't fix the underlying problem, just
the symptom.  The underlying problem will require some far more significant
revamping of concepts parsing, tsubsting, normalization, and evaluation than
I'd feel comfortable proposing at this point.