From eb1a6ab1df473c7ec0e1cbb20fc7124706326ce1 Mon Sep 17 00:00:00 2001
From: sheaf <sam.derbyshire@gmail.com>
Date: Thu, 13 Jul 2023 16:03:31 +0200
Subject: [PATCH] Don't use substTyUnchecked in newMetaTyVar
There were some comments that explained that we needed to use an
unchecked substitution function because of issue #12931, but that
has since been fixed, so we should be able to use substTy instead now.
---
compiler/GHC/Tc/Utils/TcMType.hs | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/compiler/GHC/Tc/Utils/TcMType.hs b/compiler/GHC/Tc/Utils/TcMType.hs
index 55cad5847284..239b293a9150 100644
--- a/compiler/GHC/Tc/Utils/TcMType.hs
+++ b/compiler/GHC/Tc/Utils/TcMType.hs
@@ -1001,16 +1001,7 @@ new_meta_tv_x info subst tv
; let subst1 = extendTvSubstWithClone subst tv new_tv
; return (subst1, new_tv) }
where
- substd_kind = substTyUnchecked subst (tyVarKind tv)
- -- NOTE: #12549 is fixed so we could use
- -- substTy here, but the tc_infer_args problem
- -- is not yet fixed so leaving as unchecked for now.
- -- OLD NOTE:
- -- Unchecked because we call newMetaTyVarX from
- -- tcInstTyBinder, which is called from tcInferTyApps
- -- which does not yet take enough trouble to ensure
- -- the in-scope set is right; e.g. #12785 trips
- -- if we use substTy here
+ substd_kind = substTy subst (tyVarKind tv)
newMetaTyVarTyAtLevel :: TcLevel -> TcKind -> TcM TcType
newMetaTyVarTyAtLevel tc_lvl kind
--
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