https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104594
--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> --- N.B. coerce_template_parms sometimes does encode the implicit conversion for a dependent NTTP argument, but only for sake of specialization matching (in light of 'auto' template parms IIUC), the IMPLICIT_CONV_EXPR built is a no-op otherwise.