Remove dataConSig

As suggested in #17291

3 files changed, 4 insertions, 20 deletions

diff --git a/compiler/basicTypes/DataCon.hs b/compiler/basicTypes/DataCon.hs
index 47eb7a838b..d48ecead11 100644
--- a/compiler/basicTypes/DataCon.hs
+++ b/compiler/basicTypes/DataCon.hs
@@ -27,7 +27,7 @@ module DataCon (
         mkDataCon, buildAlgTyCon, buildSynTyCon, fIRST_TAG,
 
         -- ** Type deconstruction
-        dataConRepType, dataConSig, dataConInstSig, dataConFullSig,
+        dataConRepType, dataConInstSig, dataConFullSig,
         dataConName, dataConIdentity, dataConTag, dataConTagZ,
         dataConTyCon, dataConOrigTyCon,
         dataConUserType,
@@ -1207,22 +1207,6 @@ dataConBoxer :: DataCon -> Maybe DataConBoxer
 dataConBoxer (MkData { dcRep = DCR { dcr_boxer = boxer } }) = Just boxer
 dataConBoxer _ = Nothing
 
--- | The \"signature\" of the 'DataCon' returns, in order:
---
--- 1) The result of 'dataConUnivAndExTyCoVars',
---
--- 2) All the 'ThetaType's relating to the 'DataCon' (coercion, dictionary,
---    implicit parameter - whatever), including dependent GADT equalities.
---    Dependent GADT equalities are *also* listed in return value (1), so be
---    careful!
---
--- 3) The type arguments to the constructor
---
--- 4) The /original/ result type of the 'DataCon'
-dataConSig :: DataCon -> ([TyCoVar], ThetaType, [Type], Type)
-dataConSig con@(MkData {dcOrigArgTys = arg_tys, dcOrigResTy = res_ty})
-  = (dataConUnivAndExTyCoVars con, dataConTheta con, arg_tys, res_ty)
-
 dataConInstSig
   :: DataCon
   -> [Type]    -- Instantiate the *universal* tyvars with these types
diff --git a/compiler/main/GHC.hs b/compiler/main/GHC.hs
index 80131c6329..def7065ab6 100644
--- a/compiler/main/GHC.hs
+++ b/compiler/main/GHC.hs
@@ -196,7 +196,7 @@ module GHC (
 
         -- ** Data constructors
         DataCon,
-        dataConSig, dataConType, dataConTyCon, dataConFieldLabels,
+        dataConType, dataConTyCon, dataConFieldLabels,
         dataConIsInfix, isVanillaDataCon, dataConUserType,
         dataConSrcBangs,
         StrictnessMark(..), isMarkedStrict,
diff --git a/compiler/typecheck/TcTyClsDecls.hs b/compiler/typecheck/TcTyClsDecls.hs
index bfd5567949..0695dd8970 100644
--- a/compiler/typecheck/TcTyClsDecls.hs
+++ b/compiler/typecheck/TcTyClsDecls.hs
@@ -3467,7 +3467,7 @@ checkValidTyCon tc
                 -- NB: this check assumes that all the constructors of a given
                 -- data type use the same type variables
         where
-        (_, _, _, res1) = dataConSig con1
+        res1 = dataConOrigResTy con1
         fty1 = dataConFieldType con1 lbl
         lbl = flLabel label
 
@@ -3475,7 +3475,7 @@ checkValidTyCon tc
             = do { checkFieldCompat lbl con1 con2 res1 res2 fty1 fty2
                  ; checkFieldCompat lbl con2 con1 res2 res1 fty2 fty1 }
             where
-                (_, _, _, res2) = dataConSig con2
+                res2 = dataConOrigResTy con2
                 fty2 = dataConFieldType con2 lbl
 
 checkPartialRecordField :: [DataCon] -> FieldLabel -> TcM ()