Small refactor of getRuntimeRep

Instead of using a string argument, use HasDebugCallStack.
(Oddly, some functions were using both!)

Plus, use getRuntimeRep rather than getRuntimeRep_maybe when
if the caller panics on Nothing. Less code, and a better debug
stack.

12 files changed, 55 insertions, 61 deletions

diff --git a/compiler/coreSyn/MkCore.hs b/compiler/coreSyn/MkCore.hs
index 5a29994d0e..5fe0392315 100644
--- a/compiler/coreSyn/MkCore.hs
+++ b/compiler/coreSyn/MkCore.hs
@@ -362,7 +362,7 @@ mkCoreUbxTup :: [Type] -> [CoreExpr] -> CoreExpr
 mkCoreUbxTup tys exps
   = ASSERT( tys `equalLength` exps)
     mkCoreConApps (tupleDataCon Unboxed (length tys))
-             (map (Type . getRuntimeRep "mkCoreUbxTup") tys ++ map Type tys ++ exps)
+             (map (Type . getRuntimeRep) tys ++ map Type tys ++ exps)
 
 -- | Make a core tuple of the given boxity
 mkCoreTupBoxity :: Boxity -> [CoreExpr] -> CoreExpr
@@ -651,7 +651,7 @@ mkRuntimeErrorApp
         -> CoreExpr
 
 mkRuntimeErrorApp err_id res_ty err_msg
-  = mkApps (Var err_id) [ Type (getRuntimeRep "mkRuntimeErrorApp" res_ty)
+  = mkApps (Var err_id) [ Type (getRuntimeRep res_ty)
                         , Type res_ty, err_string ]
   where
     err_string = Lit (mkMachString err_msg)
diff --git a/compiler/deSugar/DsBinds.hs b/compiler/deSugar/DsBinds.hs
index c13b2eac0a..9d0cbfbdb9 100644
--- a/compiler/deSugar/DsBinds.hs
+++ b/compiler/deSugar/DsBinds.hs
@@ -1185,7 +1185,7 @@ dsEvTerm (EvDelayedError ty msg) = return $ dsEvDelayedError ty msg
 
 dsEvDelayedError :: Type -> FastString -> CoreExpr
 dsEvDelayedError ty msg
-  = Var errorId `mkTyApps` [getRuntimeRep "dsEvTerm" ty, ty] `mkApps` [litMsg]
+  = Var errorId `mkTyApps` [getRuntimeRep ty, ty] `mkApps` [litMsg]
   where
     errorId = tYPE_ERROR_ID
     litMsg  = Lit (MachStr (fastStringToByteString msg))
@@ -1261,8 +1261,8 @@ ds_ev_typeable ty (EvTypeableTrFun ev1 ev2)
        ; mkTrFun <- dsLookupGlobalId mkTrFunName
                     -- mkTrFun :: forall r1 r2 (a :: TYPE r1) (b :: TYPE r2).
                     --            TypeRep a -> TypeRep b -> TypeRep (a -> b)
-       ; let r1 = getRuntimeRep "ds_ev_typeable" t1
-             r2 = getRuntimeRep "ds_ev_typeable" t2
+       ; let r1 = getRuntimeRep t1
+             r2 = getRuntimeRep t2
        ; return $ mkApps (mkTyApps (Var mkTrFun) [r1, r2, t1, t2])
                          [ e1, e2 ]
        }
diff --git a/compiler/deSugar/DsExpr.hs b/compiler/deSugar/DsExpr.hs
index 048d558825..2d86b8438a 100644
--- a/compiler/deSugar/DsExpr.hs
+++ b/compiler/deSugar/DsExpr.hs
@@ -380,7 +380,7 @@ ds_expr _ (ExplicitTuple tup_args boxity)
 ds_expr _ (ExplicitSum alt arity expr types)
   = do { core_expr <- dsLExpr expr
        ; return $ mkCoreConApps (sumDataCon alt arity)
-                                (map (Type . getRuntimeRep "dsExpr ExplicitSum") types ++
+                                (map (Type . getRuntimeRep) types ++
                                  map Type types ++
                                  [core_expr]) }
 
diff --git a/compiler/deSugar/DsUtils.hs b/compiler/deSugar/DsUtils.hs
index a1f3a143f3..088db2c568 100644
--- a/compiler/deSugar/DsUtils.hs
+++ b/compiler/deSugar/DsUtils.hs
@@ -344,7 +344,7 @@ sort_alts = sortWith (dataConTag . alt_pat)
 mkPatSynCase :: Id -> Type -> CaseAlt PatSyn -> CoreExpr -> DsM CoreExpr
 mkPatSynCase var ty alt fail = do
     matcher <- dsLExpr $ mkLHsWrap wrapper $
-                         nlHsTyApp matcher [getRuntimeRep "mkPatSynCase" ty, ty]
+                         nlHsTyApp matcher [getRuntimeRep ty, ty]
     let MatchResult _ mkCont = match_result
     cont <- mkCoreLams bndrs <$> mkCont fail
     return $ mkCoreAppsDs (text "patsyn" <+> ppr var) matcher [Var var, ensure_unstrict cont, Lam voidArgId fail]
@@ -471,7 +471,7 @@ mkErrorAppDs err_id ty msg = do
         full_msg = showSDoc dflags (hcat [ppr src_loc, vbar, msg])
         core_msg = Lit (mkMachString full_msg)
         -- mkMachString returns a result of type String#
-    return (mkApps (Var err_id) [Type (getRuntimeRep "mkErrorAppDs" ty), Type ty, core_msg])
+    return (mkApps (Var err_id) [Type (getRuntimeRep ty), Type ty, core_msg])
 
 {-
 'mkCoreAppDs' and 'mkCoreAppsDs' hand the special-case desugaring of 'seq'.
diff --git a/compiler/iface/TcIface.hs b/compiler/iface/TcIface.hs
index 9e0616518f..d17e2351e3 100644
--- a/compiler/iface/TcIface.hs
+++ b/compiler/iface/TcIface.hs
@@ -1404,7 +1404,7 @@ tcIfaceExpr (IfaceTuple sort args)
        ; let con_tys = map exprType args'
              some_con_args = map Type con_tys ++ args'
              con_args = case sort of
-               UnboxedTuple -> map (Type . getRuntimeRep "tcIfaceExpr") con_tys ++ some_con_args
+               UnboxedTuple -> map (Type . getRuntimeRep) con_tys ++ some_con_args
                _            -> some_con_args
                         -- Put the missing type arguments back in
              con_id   = dataConWorkId (tyConSingleDataCon tc)
diff --git a/compiler/prelude/TysWiredIn.hs b/compiler/prelude/TysWiredIn.hs
index 5a8c4aae78..37e76f9b73 100644
--- a/compiler/prelude/TysWiredIn.hs
+++ b/compiler/prelude/TysWiredIn.hs
@@ -1487,7 +1487,7 @@ mkTupleTy :: Boxity -> [Type] -> Type
 mkTupleTy Boxed   [ty] = ty
 mkTupleTy Boxed   tys  = mkTyConApp (tupleTyCon Boxed (length tys)) tys
 mkTupleTy Unboxed tys  = mkTyConApp (tupleTyCon Unboxed (length tys))
-                                        (map (getRuntimeRep "mkTupleTy") tys ++ tys)
+                                        (map getRuntimeRep tys ++ tys)
 
 -- | Build the type of a small tuple that holds the specified type of thing
 mkBoxedTupleTy :: [Type] -> Type
@@ -1505,7 +1505,7 @@ unitTy = mkTupleTy Boxed []
 
 mkSumTy :: [Type] -> Type
 mkSumTy tys = mkTyConApp (sumTyCon (length tys))
-                         (map (getRuntimeRep "mkSumTy") tys ++ tys)
+                         (map getRuntimeRep tys ++ tys)
 
 {- *********************************************************************
 *                                                                      *
diff --git a/compiler/typecheck/TcExpr.hs b/compiler/typecheck/TcExpr.hs
index 801e58a043..efaa4c642e 100644
--- a/compiler/typecheck/TcExpr.hs
+++ b/compiler/typecheck/TcExpr.hs
@@ -396,7 +396,7 @@ tcExpr expr@(OpApp arg1 op fix arg2) res_ty
 
        ; op_id  <- tcLookupId op_name
        ; res_ty <- readExpType res_ty
-       ; let op' = L loc (mkHsWrap (mkWpTyApps [ getRuntimeRep "tcExpr ($)" res_ty
+       ; let op' = L loc (mkHsWrap (mkWpTyApps [ getRuntimeRep res_ty
                                                , arg2_sigma
                                                , res_ty])
                                    (HsVar (L lv op_id)))
diff --git a/compiler/typecheck/TcHsType.hs b/compiler/typecheck/TcHsType.hs
index 034c3917e3..dab708c290 100644
--- a/compiler/typecheck/TcHsType.hs
+++ b/compiler/typecheck/TcHsType.hs
@@ -642,7 +642,7 @@ tc_hs_type mode rn_ty@(HsSumTy hs_tys) exp_kind
   = do { let arity = length hs_tys
        ; arg_kinds <- mapM (\_ -> newOpenTypeKind) hs_tys
        ; tau_tys   <- zipWithM (tc_lhs_type mode) hs_tys arg_kinds
-       ; let arg_reps = map (getRuntimeRepFromKind "tc_hs_type HsSumTy") arg_kinds
+       ; let arg_reps = map getRuntimeRepFromKind arg_kinds
              arg_tys  = arg_reps ++ tau_tys
        ; checkExpectedKind rn_ty
                            (mkTyConApp (sumTyCon arity) arg_tys)
@@ -774,7 +774,7 @@ finish_tuple rn_ty tup_sort tau_tys tau_kinds exp_kind
        ; checkExpectedKind rn_ty (mkTyConApp tycon arg_tys) res_kind exp_kind }
   where
     arity = length tau_tys
-    tau_reps = map (getRuntimeRepFromKind "finish_tuple") tau_kinds
+    tau_reps = map getRuntimeRepFromKind tau_kinds
     res_kind = case tup_sort of
                  UnboxedTuple    -> unboxedTupleKind tau_reps
                  BoxedTuple      -> liftedTypeKind
diff --git a/compiler/typecheck/TcInstDcls.hs b/compiler/typecheck/TcInstDcls.hs
index 36a4b41983..a3da31dffd 100644
--- a/compiler/typecheck/TcInstDcls.hs
+++ b/compiler/typecheck/TcInstDcls.hs
@@ -1327,8 +1327,7 @@ tcMethods dfun_id clas tyvars dfun_ev_vars inst_tys
         error_rhs dflags = L inst_loc $ HsApp error_fun (error_msg dflags)
         error_fun    = L inst_loc $
                        wrapId (mkWpTyApps
-                                [ getRuntimeRep "tcInstanceMethods.tc_default" meth_tau
-                                , meth_tau])
+                                [ getRuntimeRep meth_tau, meth_tau])
                               nO_METHOD_BINDING_ERROR_ID
         error_msg dflags = L inst_loc (HsLit (HsStringPrim noSourceText
                                               (unsafeMkByteString (error_string dflags))))
diff --git a/compiler/typecheck/TcRnDriver.hs b/compiler/typecheck/TcRnDriver.hs
index ab80cf90df..da407b8eeb 100644
--- a/compiler/typecheck/TcRnDriver.hs
+++ b/compiler/typecheck/TcRnDriver.hs
@@ -2120,7 +2120,7 @@ tcGhciStmts stmts
                        (noLoc $ ExplicitList unitTy Nothing (map mk_item ids)) ;
             mk_item id = let ty_args = [idType id, unitTy] in
                          nlHsApp (nlHsTyApp unsafeCoerceId
-                                   (map (getRuntimeRep "tcGhciStmts") ty_args ++ ty_args))
+                                   (map getRuntimeRep ty_args ++ ty_args))
                                  (nlHsVar id) ;
             stmts = tc_stmts ++ [noLoc (mkLastStmt ret_expr)]
         } ;
diff --git a/compiler/types/Type.hs b/compiler/types/Type.hs
index df7333bf1d..664f00164b 100644
--- a/compiler/types/Type.hs
+++ b/compiler/types/Type.hs
@@ -691,18 +691,19 @@ repSplitAppTy_maybe :: Type -> Maybe (Type,Type)
 -- ^ Does the AppTy split as in 'splitAppTy_maybe', but assumes that
 -- any Core view stuff is already done
 repSplitAppTy_maybe (FunTy ty1 ty2)
-  | Just rep1 <- getRuntimeRep_maybe ty1
-  , Just rep2 <- getRuntimeRep_maybe ty2
   = Just (TyConApp funTyCon [rep1, rep2, ty1], ty2)
+  where
+    rep1 = getRuntimeRep ty1
+    rep2 = getRuntimeRep ty2
 
-  | otherwise
-  = pprPanic "repSplitAppTy_maybe" (ppr ty1 $$ ppr ty2)
 repSplitAppTy_maybe (AppTy ty1 ty2)
   = Just (ty1, ty2)
+
 repSplitAppTy_maybe (TyConApp tc tys)
   | mightBeUnsaturatedTyCon tc || tys `lengthExceeds` tyConArity tc
   , Just (tys', ty') <- snocView tys
   = Just (TyConApp tc tys', ty')    -- Never create unsaturated type family apps!
+
 repSplitAppTy_maybe _other = Nothing
 
 -- this one doesn't braek apart (c => t).
@@ -715,12 +716,12 @@ tcRepSplitAppTy_maybe (FunTy ty1 ty2)
   | isConstraintKind (typeKind ty1)
   = Nothing  -- See Note [Decomposing fat arrow c=>t]
 
-  | Just rep1 <- getRuntimeRep_maybe ty1
-  , Just rep2 <- getRuntimeRep_maybe ty2
+  | otherwise
   = Just (TyConApp funTyCon [rep1, rep2, ty1], ty2)
+  where
+    rep1 = getRuntimeRep ty1
+    rep2 = getRuntimeRep ty2
 
-  | otherwise
-  = pprPanic "repSplitAppTy_maybe" (ppr ty1 $$ ppr ty2)
 tcRepSplitAppTy_maybe (AppTy ty1 ty2)    = Just (ty1, ty2)
 tcRepSplitAppTy_maybe (TyConApp tc tys)
   | mightBeUnsaturatedTyCon tc || tys `lengthExceeds` tyConArity tc
@@ -743,16 +744,17 @@ tcSplitTyConApp_maybe ty                         = tcRepSplitTyConApp_maybe ty
 -- | Like 'tcSplitTyConApp_maybe' but doesn't look through type synonyms.
 tcRepSplitTyConApp_maybe :: HasCallStack => Type -> Maybe (TyCon, [Type])
 -- Defined here to avoid module loops between Unify and TcType.
-tcRepSplitTyConApp_maybe (TyConApp tc tys)          = Just (tc, tys)
+tcRepSplitTyConApp_maybe (TyConApp tc tys)
+  = Just (tc, tys)
+
 tcRepSplitTyConApp_maybe (FunTy arg res)
-  | Just arg_rep <- getRuntimeRep_maybe arg
-  , Just res_rep <- getRuntimeRep_maybe res
   = Just (funTyCon, [arg_rep, res_rep, arg, res])
+  where
+    arg_rep = getRuntimeRep arg
+    res_rep = getRuntimeRep res
 
-  | otherwise
-  = pprPanic "tcRepSplitTyConApp_maybe" (ppr arg $$ ppr res)
-tcRepSplitTyConApp_maybe _                          = Nothing
-
+tcRepSplitTyConApp_maybe _
+  = Nothing
 
 -------------
 splitAppTy :: Type -> (Type, Type)
@@ -779,13 +781,12 @@ splitAppTys ty = split ty ty []
         in
         (TyConApp tc tc_args1, tc_args2 ++ args)
     split _   (FunTy ty1 ty2) args
-      | Just rep1 <- getRuntimeRep_maybe ty1
-      , Just rep2 <- getRuntimeRep_maybe ty2
       = ASSERT( null args )
         (TyConApp funTyCon [], [rep1, rep2, ty1, ty2])
+      where
+        rep1 = getRuntimeRep ty1
+        rep2 = getRuntimeRep ty2
 
-      | otherwise
-      = pprPanic "splitAppTys" (ppr ty1 $$ ppr ty2 $$ ppr args)
     split orig_ty _                     args  = (orig_ty, args)
 
 -- | Like 'splitAppTys', but doesn't look through type synonyms
@@ -800,13 +801,12 @@ repSplitAppTys ty = split ty []
         in
         (TyConApp tc tc_args1, tc_args2 ++ args)
     split (FunTy ty1 ty2) args
-      | Just rep1 <- getRuntimeRep_maybe ty1
-      , Just rep2 <- getRuntimeRep_maybe ty2
       = ASSERT( null args )
         (TyConApp funTyCon [], [rep1, rep2, ty1, ty2])
+      where
+        rep1 = getRuntimeRep ty1
+        rep2 = getRuntimeRep ty2
 
-      | otherwise
-      = pprPanic "repSplitAppTys" (ppr ty1 $$ ppr ty2 $$ ppr args)
     split ty args = (ty, args)
 
 {-
@@ -1085,7 +1085,7 @@ tyConAppArgs_maybe (FunTy arg res)
   | Just rep1 <- getRuntimeRep_maybe arg
   , Just rep2 <- getRuntimeRep_maybe res
   = Just [rep1, rep2, arg, res]
-tyConAppArgs_maybe _                = Nothing
+tyConAppArgs_maybe _  = Nothing
 
 tyConAppArgs :: Type -> [Type]
 tyConAppArgs ty = tyConAppArgs_maybe ty `orElse` pprPanic "tyConAppArgs" (ppr ty)
@@ -1116,12 +1116,9 @@ splitTyConApp_maybe ty                           = repSplitTyConApp_maybe ty
 repSplitTyConApp_maybe :: HasDebugCallStack => Type -> Maybe (TyCon, [Type])
 repSplitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
 repSplitTyConApp_maybe (FunTy arg res)
-  | Just rep1 <- getRuntimeRep_maybe arg
-  , Just rep2 <- getRuntimeRep_maybe res
-  = Just (funTyCon, [rep1, rep2, arg, res])
-  | otherwise
-  = pprPanic "repSplitTyConApp_maybe"
-             (ppr arg $$ ppr res $$ ppr (typeKind res))
+  | Just arg_rep <- getRuntimeRep_maybe arg
+  , Just res_rep <- getRuntimeRep_maybe res
+  = Just (funTyCon, [arg_rep, res_rep, arg, res])
 repSplitTyConApp_maybe _ = Nothing
 
 -- | Attempts to tease a list type apart and gives the type of the elements if
@@ -1936,7 +1933,7 @@ isFamFreeTy (CoercionTy _)    = False  -- Not sure about this
 -- levity polymorphic), and panics if the kind does not have the shape
 -- TYPE r.
 isLiftedType_maybe :: HasDebugCallStack => Type -> Maybe Bool
-isLiftedType_maybe ty = go (getRuntimeRep "isLiftedType_maybe" ty)
+isLiftedType_maybe ty = go (getRuntimeRep ty)
   where
     go rr | Just rr' <- coreView rr = go rr'
     go (TyConApp lifted_rep [])
@@ -1978,24 +1975,21 @@ getRuntimeRep_maybe = getRuntimeRepFromKind_maybe . typeKind
 
 -- | Extract the RuntimeRep classifier of a type. For instance,
 -- @getRuntimeRep_maybe Int = LiftedRep@. Panics if this is not possible.
-getRuntimeRep :: HasDebugCallStack
-              => String   -- ^ Printed in case of an error
-              -> Type -> Type
-getRuntimeRep err ty =
-    case getRuntimeRep_maybe ty of
+getRuntimeRep :: HasDebugCallStack => Type -> Type
+getRuntimeRep ty
+  = case getRuntimeRep_maybe ty of
       Just r  -> r
-      Nothing -> pprPanic "getRuntimeRep"
-                          (text err $$ ppr ty <+> dcolon <+> ppr (typeKind ty))
+      Nothing -> pprPanic "getRuntimeRep" (ppr ty <+> dcolon <+> ppr (typeKind ty))
 
 -- | Extract the RuntimeRep classifier of a type from its kind. For example,
 -- @getRuntimeRepFromKind * = LiftedRep@; Panics if this is not possible.
 getRuntimeRepFromKind :: HasDebugCallStack
-                      => String -> Type -> Type
-getRuntimeRepFromKind err k =
+                      => Type -> Type
+getRuntimeRepFromKind k =
     case getRuntimeRepFromKind_maybe k of
       Just r  -> r
       Nothing -> pprPanic "getRuntimeRepFromKind"
-                          (text err $$ ppr k <+> dcolon <+> ppr (typeKind k))
+                           (ppr k <+> dcolon <+> ppr (typeKind k))
 
 -- | Extract the RuntimeRep classifier of a type from its kind. For example,
 -- @getRuntimeRepFromKind * = LiftedRep@; Returns 'Nothing' if this is not
@@ -2013,14 +2007,14 @@ getRuntimeRepFromKind_maybe = go
 
 isUnboxedTupleType :: Type -> Bool
 isUnboxedTupleType ty
-  = tyConAppTyCon (getRuntimeRep "isUnboxedTupleType" ty) `hasKey` tupleRepDataConKey
+  = tyConAppTyCon (getRuntimeRep ty) `hasKey` tupleRepDataConKey
   -- NB: Do not use typePrimRep, as that can't tell the difference between
   -- unboxed tuples and unboxed sums
 
 
 isUnboxedSumType :: Type -> Bool
 isUnboxedSumType ty
-  = tyConAppTyCon (getRuntimeRep "isUnboxedSumType" ty) `hasKey` sumRepDataConKey
+  = tyConAppTyCon (getRuntimeRep ty) `hasKey` sumRepDataConKey
 
 -- | See "Type#type_classification" for what an algebraic type is.
 -- Should only be applied to /types/, as opposed to e.g. partially
diff --git a/compiler/vectorise/Vectorise/Exp.hs b/compiler/vectorise/Vectorise/Exp.hs
index f4c1361d74..9224aeac4f 100644
--- a/compiler/vectorise/Vectorise/Exp.hs
+++ b/compiler/vectorise/Vectorise/Exp.hs
@@ -360,7 +360,8 @@ vectExpr (_, AnnApp (_, AnnApp (_, AnnVar v) (_, AnnType ty)) err)
   | v == pAT_ERROR_ID
   = do
     { (vty, lty) <- vectAndLiftType ty
-    ; return (mkCoreApps (Var v) [Type (getRuntimeRep "vectExpr" vty), Type vty, err'], mkCoreApps (Var v) [Type lty, err'])
+    ; return (mkCoreApps (Var v) [Type (getRuntimeRep vty), Type vty, err'],
+              mkCoreApps (Var v) [Type lty, err'])
     }
   where
     err' = deAnnotate err