diff options
Diffstat (limited to 'compiler/GHC/Core/Type.hs')
| -rw-r--r-- | compiler/GHC/Core/Type.hs | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/compiler/GHC/Core/Type.hs b/compiler/GHC/Core/Type.hs index 1b5a21b733..e05acf1881 100644 --- a/compiler/GHC/Core/Type.hs +++ b/compiler/GHC/Core/Type.hs @@ -279,6 +279,7 @@ import {-# SOURCE #-} GHC.Core.Coercion , isReflexiveCo, seqCo , topNormaliseNewType_maybe ) +import {-# SOURCE #-} GHC.Tc.Utils.TcType ( isConcreteTyVar ) -- others import GHC.Utils.Misc @@ -3549,11 +3550,8 @@ distinct uniques, they are treated as equal at all times except during type inference. -} --- | Tests whether the given kind is a constructor tree --- (that is, constructors at every node). --- --- E.g. @False@ for @TYPE k@, @TYPE (F Int)@ --- @True@ for @TYPE 'LiftedRep@ +-- | Checks that a kind of the form 'Type', 'Constraint' +-- or @'TYPE r@ is concrete. See 'isConcrete'. -- -- __Precondition:__ The type has kind @('TYPE' blah)@. isFixedRuntimeRepKind :: HasDebugCallStack => Kind -> Bool @@ -3564,19 +3562,24 @@ isFixedRuntimeRepKind k where _is_type = classifiesTypeWithValues k --- | Tests whether the given type is a constructor tree, --- consisting only of concrete type constructors and applications. +-- | Tests whether the given type is concrete, i.e. it +-- whether it consists only of concrete type constructors, +-- concrete type variables, and applications. +-- +-- See Note [Concrete types] in GHC.Tc.Utils.Concrete. isConcrete :: Type -> Bool isConcrete = go where go ty | Just ty' <- coreView ty = go ty' - go TyVarTy{} = False - go AppTy{} = False -- it can't be a TyConApp + go (TyVarTy tv) = isConcreteTyVar tv + go (AppTy ty1 ty2) = go ty1 && go ty2 go (TyConApp tc tys) | isConcreteTyCon tc = all go tys | otherwise = False go ForAllTy{} = False go (FunTy _ w t1 t2) = go w && go t1 && go t2 + -- NB: no need to check the kinds of 't1' and 't2'. + -- See Note [Concrete types] in GHC.Tc.Utils.Concrete. go LitTy{} = True go CastTy{} = False go CoercionTy{} = False |