 (GRHS guards body)
 = sep [vbar <+> interpp'SP guards, pp_rhs ctxt body]

pp_rhs :: 
pprGRHS ctxt (GRHS guards body)
 = sep [vbar <+> interpp'SP guards, pp_rhs ctxt body]
pprGRHS ctxt (GRHS guards body)
 = sep [vbar <+> interpp'SP guards, pp_rhs ctxt body]