diff options
Diffstat (limited to 'compiler/GHC/Core/FamInstEnv.hs')
| -rw-r--r-- | compiler/GHC/Core/FamInstEnv.hs | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/compiler/GHC/Core/FamInstEnv.hs b/compiler/GHC/Core/FamInstEnv.hs index 4a685ba096..a693927db4 100644 --- a/compiler/GHC/Core/FamInstEnv.hs +++ b/compiler/GHC/Core/FamInstEnv.hs @@ -352,7 +352,10 @@ UniqFM and UniqDFM. See Note [Deterministic UniqFM]. -} -type FamInstEnv = UniqDFM FamilyInstEnv -- Maps a family to its instances +-- Internally we sometimes index by Name instead of TyCon despite +-- of what the type says. This is safe since +-- getUnique (tyCon) == getUniqe (tcName tyCon) +type FamInstEnv = UniqDFM TyCon FamilyInstEnv -- Maps a family to its instances -- See Note [FamInstEnv] -- See Note [FamInstEnv determinism] @@ -365,6 +368,14 @@ newtype FamilyInstEnv instance Outputable FamilyInstEnv where ppr (FamIE fs) = text "FamIE" <+> vcat (map ppr fs) +-- | Index a FamInstEnv by the tyCons name. +toNameInstEnv :: FamInstEnv -> UniqDFM Name FamilyInstEnv +toNameInstEnv = unsafeCastUDFMKey + +-- | Create a FamInstEnv from Name indices. +fromNameInstEnv :: UniqDFM Name FamilyInstEnv -> FamInstEnv +fromNameInstEnv = unsafeCastUDFMKey + -- INVARIANTS: -- * The fs_tvs are distinct in each FamInst -- of a range value of the map (so we can safely unify them) @@ -398,7 +409,7 @@ extendFamInstEnvList inst_env fis = foldl' extendFamInstEnv inst_env fis extendFamInstEnv :: FamInstEnv -> FamInst -> FamInstEnv extendFamInstEnv inst_env ins_item@(FamInst {fi_fam = cls_nm}) - = addToUDFM_C add inst_env cls_nm (FamIE [ins_item]) + = fromNameInstEnv $ addToUDFM_C add (toNameInstEnv inst_env) cls_nm (FamIE [ins_item]) where add (FamIE items) _ = FamIE (ins_item:items) |