diff options
| -rw-r--r-- | compiler/GHC/Tc/Solver/Canonical.hs | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/compiler/GHC/Tc/Solver/Canonical.hs b/compiler/GHC/Tc/Solver/Canonical.hs index e4020bdfc5..341e5323dc 100644 --- a/compiler/GHC/Tc/Solver/Canonical.hs +++ b/compiler/GHC/Tc/Solver/Canonical.hs @@ -935,10 +935,22 @@ It's as if we treat (->) and (=>) as different type constructors. canEqNC :: CtEvidence -> EqRel -> Type -> Type -> TcS (StopOrContinue Ct) canEqNC ev eq_rel ty1 ty2 + = do { (ty1', co1) <- rewrite_shallow ev ty1 + ; (ty2', co2) <- rewrite_shallow ev ty2 + -- TODO: We are dropping the "pretty" type here... and the rewritten + -- flag now indicates "deeply rewritten"; after deeply rewriting we + -- shouldn't need to retry the common-structure cases, but later we + -- might depend on having zonked/rewritten deeply. + ; new_ev <- rewriteEqEvidence ev NotSwapped ty1' ty2' co1 co2 + ; can_eq_nc False new_ev eq_rel ty1' ty1' ty2' ty2' + } + +{- = do { result <- zonk_eq_types ty1 ty2 ; case result of Left (Pair ty1' ty2') -> can_eq_nc False ev eq_rel ty1' ty1 ty2' ty2 Right ty -> canEqReflexive ev eq_rel ty } +-} can_eq_nc :: Bool -- True => both types are rewritten @@ -978,9 +990,10 @@ can_eq_nc' rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2 ps_ty2 -- See Note [Eager reflexivity check] -- Check only when rewritten because the zonk_eq_types check in canEqNC takes -- care of the non-rewritten case. -can_eq_nc' True _rdr_env _envs ev ReprEq ty1 _ ty2 _ +-- TODO: not any more! +can_eq_nc' True _rdr_env _envs ev eq_rel ty1 _ ty2 _ | ty1 `tcEqType` ty2 - = canEqReflexive ev ReprEq ty1 + = canEqReflexive ev eq_rel ty1 -- When working with ReprEq, unwrap newtypes. -- See Note [Unwrap newtypes first] |