84015 seems likely to be related.
On Fri, Feb 16, 2018 at 9:04 AM, Jason Merrill <ja...@redhat.com> wrote: > On Thu, Feb 15, 2018 at 6:36 PM, Martin Sebor <mse...@gmail.com> wrote: >> A failed template deduction in template member of a template >> triggers an ICE with -std=c++17 due to what seems like >> a missing handling of invalid input. Replacing >> the gcc_unreachable() call that causes the ICE with a return >> statement indicating the deduction failure eliminates the ICE >> and restores sane diagnostics. > > Hmm, we really shouldn't have gotten there; that assert is checking > that when we see a TEMPLATE_*_PARM node in the template signature, it > corresponds to one of the actual parms of the template. Sounds like > something is going wrong in build_deduction_guide. > > Jason
