Use LHsSigWcType in DerivDeclwip/T13324

This prepares the way for the fix for Trac #13324, by
using LHsSigWcType for the instance type in DerivDecl,
but nowhere else.

See comments on Phab:D4383

2 files changed, 6 insertions, 10 deletions

diff --git a/compiler/rename/RnSource.hs b/compiler/rename/RnSource.hs
index 447871a7f2..53feacb8df 100644
--- a/compiler/rename/RnSource.hs
+++ b/compiler/rename/RnSource.hs
@@ -634,7 +634,8 @@ rnClsInstDecl (ClsInstDecl { cid_poly_ty = inst_ty, cid_binds = mbinds
                            , cid_sigs = uprags, cid_tyfam_insts = ats
                            , cid_overlap_mode = oflag
                            , cid_datafam_insts = adts })
-  = do { (inst_ty', inst_fvs) <- rnLHsInstType (text "an instance declaration") inst_ty
+  = do { let ctxt = GenericCtx (text "an instance declaration")
+       ; (inst_ty', inst_fvs) <- rnHsSigType ctxt inst_ty
        ; let (ktv_names, _, head_ty') = splitLHsInstDeclTy inst_ty'
        ; let cls = case hsTyGetAppHead_maybe head_ty' of
                      Nothing -> mkUnboundName (mkTcOccFS (fsLit "<class>"))
@@ -945,7 +946,8 @@ rnSrcDerivDecl (DerivDecl ty deriv_strat overlap)
        ; unless standalone_deriv_ok (addErr standaloneDerivErr)
        ; failIfTc (isJust deriv_strat && not deriv_strats_ok) $
            illegalDerivStrategyErr $ fmap unLoc deriv_strat
-       ; (ty', fvs) <- rnLHsInstType (text "a deriving declaration") ty
+       ; let ctxt = GenericCtx (text "a deriving declaration")
+       ; (ty', fvs) <- rnHsSigWcType ctxt ty
        ; return (DerivDecl ty' deriv_strat overlap, fvs) }
 
 standaloneDerivErr :: SDoc
@@ -1124,7 +1126,8 @@ rnHsVectDecl (HsVectClassIn s cls)
 rnHsVectDecl (HsVectClassOut _)
   = panic "RnSource.rnHsVectDecl: Unexpected 'HsVectClassOut'"
 rnHsVectDecl (HsVectInstIn instTy)
-  = do { (instTy', fvs) <- rnLHsInstType (text "a VECTORISE pragma") instTy
+  = do { let ctxt = GenericCtx (text "a VECTORISE pragma")
+       ; (instTy', fvs) <- rnHsSigType ctxt instTy
        ; return (HsVectInstIn instTy', fvs)
        }
 rnHsVectDecl (HsVectInstOut _)
diff --git a/compiler/rename/RnTypes.hs b/compiler/rename/RnTypes.hs
index b2dafb2bf7..791881bbd0 100644
--- a/compiler/rename/RnTypes.hs
+++ b/compiler/rename/RnTypes.hs
@@ -13,7 +13,6 @@ module RnTypes (
         rnHsKind, rnLHsKind,
         rnHsSigType, rnHsWcType,
         rnHsSigWcType, rnHsSigWcTypeScoped,
-        rnLHsInstType,
         newTyVarNameRn, collectAnonWildCards,
         rnConDeclFields,
         rnLTyVar,
@@ -323,12 +322,6 @@ rnImplicitBndrs bind_free_tvs doc
        ; bindLocalNamesFV vars $
          thing_inside vars }
 
-rnLHsInstType :: SDoc -> LHsSigType GhcPs -> RnM (LHsSigType GhcRn, FreeVars)
--- Rename the type in an instance or standalone deriving decl
--- The 'doc_str' is "an instance declaration" or "a VECTORISE pragma"
--- Do not try to decompose the inst_ty in case it is malformed
-rnLHsInstType doc inst_ty = rnHsSigType (GenericCtx doc) inst_ty
-
 mk_implicit_bndrs :: [Name]  -- implicitly bound
                   -> a           -- payload
                   -> FreeVars    -- FreeVars of payload