https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107525
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Assignee|unassigned at gcc dot gnu.org |redi at gcc dot gnu.org Status|NEW |ASSIGNED --- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> --- Created attachment 53825 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53825&action=edit Do not use SFINAE for propagate_const conversions I got nerd sniped by the incorrect constraint, so replaced them with base classes as you suggested. I'll probably push this next week.