[Bug c++/94454] ICE 'canonical types differ for identical types'

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94454

--- Comment #7 from Iain Sandoe <iains at gcc dot gnu.org> ---
Created attachment 48175
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48175&action=edit
un-reduced pre-processed on x86_64-linux

working on reducing this.