Let (L _ binds) expr@(L _ (HsLet _ _)))
  = sep [hang (text "let") 2 (hsep [pprBinds binds, ptext (sLit "in")]),
         ppr_lexpr expr]

ppr_expr (
ppr_expr (HsLet (L _ binds) expr@(L _ (HsLet _ _)))
  = sep [hang (text "let") 2 (hsep [pprBinds binds, ptext (sLit "in")]),
         ppr_lexpr expr]
ppr_expr (HsLet (L _ binds) expr@(L _ (HsLet _ _)))
  = sep [hang (text "let") 2 (hsep [pprBinds binds, ptext (sLit "in")]),
         ppr_lexpr expr]