diff options
Diffstat (limited to 'compiler/typecheck/TcDeriv.hs')
| -rw-r--r-- | compiler/typecheck/TcDeriv.hs | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/compiler/typecheck/TcDeriv.hs b/compiler/typecheck/TcDeriv.hs index 8076115b6c..5bdfae70ac 100644 --- a/compiler/typecheck/TcDeriv.hs +++ b/compiler/typecheck/TcDeriv.hs @@ -613,7 +613,7 @@ deriveTyData tvs tc tc_args deriv_strat deriv_pred -- Typeable is special, because Typeable :: forall k. k -> Constraint -- so the argument kind 'k' is not decomposable by splitKindFunTys -- as is the case for all other derivable type classes - ; when (length cls_arg_kinds /= 1) $ + ; when (cls_arg_kinds `lengthIsNot` 1) $ failWithTc (nonUnaryErr deriv_pred) ; let [cls_arg_kind] = cls_arg_kinds ; if className cls == typeableClassName @@ -1101,7 +1101,7 @@ mkNewTypeEqn dflags overlap_mode tvs cls cls_tys tycon tc_args rep_tycon rep_tc_args mtheta deriv_strat -- Want: instance (...) => cls (cls_tys ++ [tycon tc_args]) where ... - = ASSERT( length cls_tys + 1 == classArity cls ) + = ASSERT( cls_tys `lengthIs` (classArity cls - 1) ) case deriv_strat of Just StockStrategy -> mk_eqn_stock dflags mtheta cls cls_tys rep_tycon go_for_it_other bale_out @@ -1302,7 +1302,7 @@ mkNewTypeEqn dflags overlap_mode tvs && isNothing at_without_last_cls_tv -- Check that eta reduction is OK - eta_ok = nt_eta_arity <= length rep_tc_args + eta_ok = rep_tc_args `lengthAtLeast` nt_eta_arity -- The newtype can be eta-reduced to match the number -- of type argument actually supplied -- newtype T a b = MkT (S [a] b) deriving( Monad ) |