[Bug c++/93286] [10 Regression] ICE: tree check: did not expect class ‘type’, have ‘type’ (reference_type) in convert_from_reference, at cp/cvt.c:550 since g:e0d91792eec490d1

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93286

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:5c7938eb3f1a116b1cf9a28090f2cc5e08814ce4

commit r9-8140-g5c7938eb3f1a116b1cf9a28090f2cc5e08814ce4
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jan 16 16:55:39 2020 -0500

    PR c++/93286 - ICE with __is_constructible and variadic template.

    Here we had been recursing in tsubst_copy_and_build if type2 was a
TREE_LIST
    because that function knew how to deal with pack expansions, and tsubst
    didn't.  But tsubst_copy_and_build expects to be dealing with expressions,
    so we crash when trying to convert_from_reference a type.

        * pt.c (tsubst) [TREE_LIST]: Handle pack expansion.
        (tsubst_copy_and_build) [TRAIT_EXPR]: Always use tsubst for type2.