[Bug c++/93761] ICE when compiling a standard header as a header unit

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93761

--- Comment #3 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
The modules branch identifies itself as:

gcc version 10.0.1 20200211 (experimental) [devel/c++-modules
fe76dae46c6:20200212-0942] (GCC) 

I added the branch name to the [...] piece last week.

Its ICE and --help output also says:

For bug reporting instructions, please see:
<https://gcc.gnu.org/wiki/cxx-modules#Bugs>.

I would like to keep the actual version number tracking the (frequent) merges
from trunk, rather than invent something else.  I guess the '(experimental)'
part could say something else.  (modules)?  Though I don't know what scripts
out there might barf on that.

As to Chris's report -- this is a known defect mentioned on the modules wiki
page -- concepts support is incomplete.

I suspect on trunk I should add modules-specific smarts to the parser error
message route, so it can say something clueful.