https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114795
Nathaniel Shead <nshead at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=114600,
| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=99000
CC| |nshead at gcc dot gnu.org
--- Comment #3 from Nathaniel Shead <nshead at gcc dot gnu.org> ---
Similarly to PR114600 (and PR99000 and maybe some others?) this is because we
don't support textual redefinitions yet (`#include` after `import` naming the
same things). See https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Modules.html:
G++’s modules support is not complete. Other than bugs, the known missing
pieces are:
[...]
Textual merging of reachable GM entities
Entities may be multiply defined across different header-units. These must
be de-duplicated, and this is implemented across imports, or when an import
redefines a textually-defined entity. However the reverse is not
implemented—textually redefining an entity that has been defined in an imported
header-unit. A redefinition error is emitted.
A workaround is to ensure that `#include` always goes before `import`, or to
use a header module here rather than `#include`.
FWIW this particular ICE is because we hit this assertion:
/* Don't add decls after definition. */
gcc_assert (TYPE_BEING_DEFINED (current_class_type)
/* We can add lambda types when late parsing default
arguments. */
|| LAMBDA_TYPE_P (TREE_TYPE (decl)));
but the class has already been defined earlier, by the import.
The other issue here is that we didn't discard the entire GMF here, I suppose
possibly because of a similar issue as described in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114630#c2.
