Address #11471 by putting RuntimeRep in kinds.wip/runtime-rep

See Note [TYPE] in TysPrim. There are still some outstanding
pieces in #11471 though, so this doesn't actually nail the bug.

This commit also contains a few performance improvements:

* Short-cut equality checking of nullary type syns

* Compare types before kinds in eqType

* INLINE coreViewOneStarKind

* Store tycon binders separately from kinds.

This resulted in a ~10% performance improvement in compiling
the Cabal package. No change in functionality other than
performance. (This affects the interface file format, though.)

This commit updates the haddock submodule.

3 files changed, 12 insertions, 14 deletions

diff --git a/compiler/coreSyn/CoreLint.hs b/compiler/coreSyn/CoreLint.hs
index 6dbcbe4ce9..f9cb4be3b3 100644
--- a/compiler/coreSyn/CoreLint.hs
+++ b/compiler/coreSyn/CoreLint.hs
@@ -988,8 +988,8 @@ lintAndScopeId id linterF
                 (text "Non-local Id binder" <+> ppr id)
                 -- See Note [Checking for global Ids]
        ; (ty, k) <- lintInTy (idType id)
-       ; lintL (not (isLevityPolymorphic k))
-           (text "Levity polymorphic binder:" <+>
+       ; lintL (not (isRuntimeRepPolymorphic k))
+           (text "RuntimeRep-polymorphic binder:" <+>
                  (ppr id <+> dcolon <+> parens (ppr ty <+> dcolon <+> ppr k)))
        ; let id' = setIdType id ty
        ; addInScopeVar id' $ (linterF id') }
diff --git a/compiler/coreSyn/CorePrep.hs b/compiler/coreSyn/CorePrep.hs
index 4708df3f48..3f9f4c8470 100644
--- a/compiler/coreSyn/CorePrep.hs
+++ b/compiler/coreSyn/CorePrep.hs
@@ -512,7 +512,7 @@ cpeRhsE env (Var f `App` _{-type-} `App` arg)
   | f `hasKey` lazyIdKey          -- Replace (lazy a) by a
   = cpeRhsE env arg               -- See Note [lazyId magic] in MkId
 
-cpeRhsE env (Var f `App` _levity `App` _type `App` arg)
+cpeRhsE env (Var f `App` _runtimeRep `App` _type `App` arg)
     -- See Note [runRW magic] in MkId
   | f `hasKey` runRWKey           -- Replace (runRW# f) by (f realWorld#),
   = case arg of                   -- beta reducing if possible
diff --git a/compiler/coreSyn/MkCore.hs b/compiler/coreSyn/MkCore.hs
index 94a264c120..0eccccc2e4 100644
--- a/compiler/coreSyn/MkCore.hs
+++ b/compiler/coreSyn/MkCore.hs
@@ -322,13 +322,13 @@ mkCoreTup cs  = mkCoreConApps (tupleDataCon Boxed (length cs))
 
 -- | Build a small unboxed tuple holding the specified expressions,
 -- with the given types. The types must be the types of the expressions.
--- Do not include the levity specifiers; this function calculates them
+-- Do not include the RuntimeRep specifiers; this function calculates them
 -- for you.
 mkCoreUbxTup :: [Type] -> [CoreExpr] -> CoreExpr
 mkCoreUbxTup tys exps
   = ASSERT( tys `equalLength` exps)
     mkCoreConApps (tupleDataCon Unboxed (length tys))
-             (map (Type . getLevity "mkCoreUbxTup") tys ++ map Type tys ++ exps)
+             (map (Type . getRuntimeRep "mkCoreUbxTup") tys ++ map Type tys ++ exps)
 
 -- | Make a core tuple of the given boxity
 mkCoreTupBoxity :: Boxity -> [CoreExpr] -> CoreExpr
@@ -588,7 +588,8 @@ mkRuntimeErrorApp
         -> CoreExpr
 
 mkRuntimeErrorApp err_id res_ty err_msg
-  = mkApps (Var err_id) [Type (getLevity "mkRuntimeErrorApp" res_ty), Type res_ty, err_string]
+  = mkApps (Var err_id) [ Type (getRuntimeRep "mkRuntimeErrorApp" res_ty)
+                        , Type res_ty, err_string ]
   where
     err_string = Lit (mkMachString err_msg)
 
@@ -672,21 +673,18 @@ mkRuntimeErrorId name = pc_bottoming_Id1 name runtimeErrorTy
 
 runtimeErrorTy :: Type
 -- The runtime error Ids take a UTF8-encoded string as argument
-runtimeErrorTy = mkSpecSigmaTy [levity1TyVar, openAlphaTyVar] []
+runtimeErrorTy = mkSpecSigmaTy [runtimeRep1TyVar, openAlphaTyVar] []
                                (mkFunTy addrPrimTy openAlphaTy)
 
 {-
 Note [Error and friends have an "open-tyvar" forall]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 'error' and 'undefined' have types
-        error     :: forall (v :: Levity) (a :: TYPE v). String -> a
-        undefined :: forall (v :: Levity) (a :: TYPE v). a
-Notice the levity polymophism. This ensures that
-"error" can be instantiated at
-  * unboxed as well as boxed types
-  * polymorphic types
+        error     :: forall (v :: RuntimeRep) (a :: TYPE v). String -> a
+        undefined :: forall (v :: RuntimeRep) (a :: TYPE v). a
+Notice the runtime-representation polymophism. This ensures that
+"error" can be instantiated at unboxed as well as boxed types.
 This is OK because it never returns, so the return type is irrelevant.
-See Note [Sort-polymorphic tyvars accept foralls] in TcMType.
 
 
 ************************************************************************