diff options
Diffstat (limited to 'compiler/GHC/Tc/Utils/Concrete.hs')
| -rw-r--r-- | compiler/GHC/Tc/Utils/Concrete.hs | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/compiler/GHC/Tc/Utils/Concrete.hs b/compiler/GHC/Tc/Utils/Concrete.hs index 95f2a026a7..d69a3c473a 100644 --- a/compiler/GHC/Tc/Utils/Concrete.hs +++ b/compiler/GHC/Tc/Utils/Concrete.hs @@ -37,8 +37,12 @@ import GHC.Tc.Utils.TcMType ( newConcreteTyVar, isFilledMetaTyVar_maybe, writ , emitWantedEq ) import GHC.Types.Basic ( TypeOrKind(..) ) +import GHC.Types.Name ( getOccName ) +import GHC.Types.Name.Occurrence( occNameFS ) import GHC.Utils.Misc ( HasDebugCallStack ) import GHC.Utils.Outputable +import GHC.Data.FastString ( fsLit ) + import Control.Monad ( void ) import Data.Functor ( ($>) ) @@ -495,7 +499,7 @@ unifyConcrete frr_orig ty -- Create a new ConcreteTv metavariable @concrete_tv@ -- and unify @ty ~# concrete_tv@. ; _ -> - do { conc_tv <- newConcreteTyVar (ConcreteFRR frr_orig) ki + do { conc_tv <- newConcreteTyVar (ConcreteFRR frr_orig) (fsLit "cx") ki -- NB: newConcreteTyVar asserts that 'ki' is concrete. ; coToMCo <$> emitWantedEq orig KindLevel Nominal ty (mkTyVarTy conc_tv) } } } where @@ -647,9 +651,12 @@ makeTypeConcrete conc_orig ty = , TauTv <- metaTyVarInfo tv -> -- Change the MetaInfo to ConcreteTv, but retain the TcLevel do { kind <- go (tyVarKind tv) + ; let occ_fs = occNameFS (getOccName tv) + -- occ_fs: preserve the occurrence name of the original tyvar + -- This helps in error messages ; lift $ do { conc_tv <- setTcLevel (tcTyVarLevel tv) $ - newConcreteTyVar conc_orig kind + newConcreteTyVar conc_orig occ_fs kind ; let conc_ty = mkTyVarTy conc_tv ; writeMetaTyVar tv conc_ty ; return conc_ty } } |