diff options
Diffstat (limited to 'compiler/GHC/Core/Utils.hs')
| -rw-r--r-- | compiler/GHC/Core/Utils.hs | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/compiler/GHC/Core/Utils.hs b/compiler/GHC/Core/Utils.hs index afebee0678..d419c2546e 100644 --- a/compiler/GHC/Core/Utils.hs +++ b/compiler/GHC/Core/Utils.hs @@ -47,7 +47,7 @@ module GHC.Core.Utils ( exprToType, exprToCoercion_maybe, applyTypeToArgs, applyTypeToArg, dataConRepInstPat, dataConRepFSInstPat, - isEmptyTy, + isEmptyTy, normSplitTyConApp_maybe, -- * Working with ticks stripTicksTop, stripTicksTopE, stripTicksTopT, @@ -87,6 +87,7 @@ import GHC.Core.DataCon import GHC.Builtin.PrimOps import GHC.Types.Id import GHC.Types.Id.Info +import GHC.Core.FamInstEnv import GHC.Core.Type as Type import GHC.Core.Predicate import GHC.Core.TyCo.Rep( TyCoBinder(..), TyBinder ) @@ -2563,6 +2564,17 @@ isEmptyTy ty | otherwise = False +-- | If `normSplitTyConApp_maybe _ ty = Just (tc, tys, co)` +-- then `ty |> co = tc tys`. It's 'splitArgType_maybe', but looks through +-- coercions via 'topNormaliseType_maybe'. Hence the \"norm\" prefix. +normSplitTyConApp_maybe :: FamInstEnvs -> Type -> Maybe (TyCon, [Type], Coercion) +normSplitTyConApp_maybe fam_envs ty + | let (co, ty1) = topNormaliseType_maybe fam_envs ty + `orElse` (mkRepReflCo ty, ty) + , Just (tc, tc_args) <- splitTyConApp_maybe ty1 + = Just (tc, tc_args, co) +normSplitTyConApp_maybe _ _ = Nothing + {- ***************************************************** * |