pprCtO (TypeEqOrigin t1 t2)  = ptext (sLit "a type equality") <+> sep [ppr t1, char '~', ppr t2]
pprCtO (TypeEqOrigin t1 t2)  = ptext (sLit "a type equality") <+> sep [ppr t1, char '~', ppr t2]
pprCtO (TypeEqOrigin t1 t2)  = ptext (sLit "a type equality") <+> sep [ppr t1, char '~', ppr t2]