Add a note about non-deferrable constraints
It would be nice to add a Note that explains the current way we avoid deferring certain errors, using nonDeferrableOrigin
. There currently is Note [No deferring for multiplicity errors]
, but it should be expanded to cover the representation-polymorphism checks (and IsRefl#
, which currently only uses FixedRuntimeRep
origins, but that could change).