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| author | Richard Eisenberg <rae@cs.brynmawr.edu> | 2018-02-24 11:49:15 -0500 |
|---|---|---|
| committer | Richard Eisenberg <rae@cs.brynmawr.edu> | 2018-03-31 23:17:01 -0400 |
| commit | ef443820b71f5c9c2dca362217f1a9fbab6dd736 (patch) | |
| tree | ab5e11768301418498d2a1602d2798eb89668991 | |
| parent | faec8d358985e5d0bf363bd96f23fe76c9e281f7 (diff) | |
| download | haskell-ef443820b71f5c9c2dca362217f1a9fbab6dd736.tar.gz | |
Apply the interim fix for #14119 to liftCoMatch
Matching in the presence of casts can happen in liftCoMatch, too.
| -rw-r--r-- | compiler/types/Unify.hs | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/compiler/types/Unify.hs b/compiler/types/Unify.hs index 34f2fac56b..cb651ee3c3 100644 --- a/compiler/types/Unify.hs +++ b/compiler/types/Unify.hs @@ -1328,7 +1328,13 @@ ty_co_match menv subst ty co lkco rkco ty_co_match menv subst ty co lkco rkco | CastTy ty' co' <- ty - = ty_co_match menv subst ty' co (co' `mkTransCo` lkco) (co' `mkTransCo` rkco) + -- See Note [Matching in the presence of casts] + = let empty_subst = mkEmptyTCvSubst (rnInScopeSet (me_env menv)) + substed_co_l = substCo (liftEnvSubstLeft empty_subst subst) co' + substed_co_r = substCo (liftEnvSubstRight empty_subst subst) co' + in + ty_co_match menv subst ty' co (substed_co_l `mkTransCo` lkco) + (substed_co_r `mkTransCo` rkco) | CoherenceCo co1 co2 <- co = ty_co_match menv subst ty co1 (lkco `mkTransCo` mkSymCo co2) rkco |