[Bug preprocessor/69650] [6 Regression] ICE in linemap_line_start, at libcpp/line-map.c:803

["manu at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69650

--- Comment #32 from Manuel LÃpez-IbÃÃez <manu at gcc dot gnu.org> ---
(In reply to David Malcolm from comment #31)

> I may have been wrong in my earlier question on the mailing list; doesn't
> the flag value of 2 mean "LC_LEAVE"?  (is the filename meant to refer to the
> file being left, or the file being entered?  am new to this part of libcpp)

This is my understanding as well:
https://gcc.gnu.org/onlinedocs/cpp/Preprocessor-Output.html

That is, it means "leaving fish returning to 69650.c". If there is not previous
enter "fish" directive, there is a problem. An empty file means, leaving
whatever file we last entered. If there is no previous enter file directive at
all (# N "whatever" 1), then there is also a problem. One cannot leave the main
file.

It should be easy to play with the line directives to trigger both types of
error.