Re: [C++ Patch] PR 57466 (DR 1584)

[Paolo Carlini]

.. unfortunately something is wrong with this commit, thus c++/62072. 
For the time being I'm simply reverting it and adding the new testcase.

By the way, more generally, I don't understand at the moment how we can 
safely use complete_type in the middle of tsubst & co: it can emit hard 
errors about, eg, incompleteness (see c++/62072) irrespective of the 
tsubst_flags_t argument...

Thanks,
Paolo.