Misc cleanupwip/misc-fix

* Remove `getTag_RDR` (unused), `tidyKind` and `tidyOpenKind`
  (already available as `tidyType` and `tidyOpenType`)

* Remove Note [Explicit Case Statement for Specificity].
  Since 0a709dd9876e40 we require GHC 8.10 for bootstrapping.

* Change the warning to `cmpAltCon` to a panic.
  This shouldn't happen.  If it ever does, the code was wrong anyway:
  it shouldn't always return `LT`, but rather `LT` in one case
  and `GT` in the other case.

* Rename `verifyLinearConstructors` to `verifyLinearFields`

* Fix `Note [Local record selectors]` which was not referenced

* Remove vestiges of `type +v`

* Minor fixes to StaticPointers documentation, part of #15603

4 files changed, 9 insertions, 11 deletions

diff --git a/compiler/GHC/Tc/Errors/Hole.hs b/compiler/GHC/Tc/Errors/Hole.hs
index 00e948bd10..d1c727da35 100644
--- a/compiler/GHC/Tc/Errors/Hole.hs
+++ b/compiler/GHC/Tc/Errors/Hole.hs
@@ -484,12 +484,10 @@ pprHoleFit (HFDC sWrp sWrpVars sTy sProv sMs) (HoleFit {..}) =
  hang display 2 provenance
  where tyApp = sep $ zipWithEqual "pprHoleFit" pprArg vars hfWrap
          where pprArg b arg = case binderArgFlag b of
-                                -- See Note [Explicit Case Statement for Specificity]
-                                (Invisible spec) -> case spec of
-                                  SpecifiedSpec -> text "@" <> pprParendType arg
+                                Specified -> text "@" <> pprParendType arg
                                   -- Do not print type application for inferred
                                   -- variables (#16456)
-                                  InferredSpec  -> empty
+                                Inferred  -> empty
                                 Required  -> pprPanic "pprHoleFit: bad Required"
                                                          (ppr b <+> ppr arg)
        tyAppVars = sep $ punctuate comma $
diff --git a/compiler/GHC/Tc/Gen/Head.hs b/compiler/GHC/Tc/Gen/Head.hs
index 821b118ded..9fbd972f8a 100644
--- a/compiler/GHC/Tc/Gen/Head.hs
+++ b/compiler/GHC/Tc/Gen/Head.hs
@@ -483,7 +483,7 @@ tcInferRecSelId (FieldOcc sel_name lbl)
          = do { thing <- tcLookup sel_name
               ; case thing of
                     ATcId { tct_id = id }
-                      -> do { check_naughty occ id
+                      -> do { check_naughty occ id  -- See Note [Local record selectors]
                             ; check_local_id id
                             ; return id }
 
@@ -1034,11 +1034,11 @@ errors in a polymorphic situation.
 If this check fails (which isn't impossible) we get another chance; see
 Note [Converting strings] in Convert.hs
 
-Local record selectors
-~~~~~~~~~~~~~~~~~~~~~~
+Note [Local record selectors]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Record selectors for TyCons in this module are ordinary local bindings,
 which show up as ATcIds rather than AGlobals.  So we need to check for
-naughtiness in both branches.  c.f. TcTyClsBindings.mkAuxBinds.
+naughtiness in both branches.  c.f. GHC.Tc.TyCl.Utils.mkRecSelBinds.
 -}
 
 
diff --git a/compiler/GHC/Tc/Module.hs b/compiler/GHC/Tc/Module.hs
index e2a53c4f39..dca730f6f0 100644
--- a/compiler/GHC/Tc/Module.hs
+++ b/compiler/GHC/Tc/Module.hs
@@ -2708,7 +2708,7 @@ https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0179-printi
   reverse :: forall a. [a] -> [a]
 
   -- foo :: forall a f b. (Show a, Num b, Foldable f) => a -> f b -> String
-  > :type +v foo @Int
+  > :type foo @Int
   forall f b. (Show Int, Num b, Foldable f) => Int -> f b -> String
 
   Note that Show Int is still reported, because the solver never got a chance
diff --git a/compiler/GHC/Tc/Validity.hs b/compiler/GHC/Tc/Validity.hs
index de007d0fac..c5dc68469f 100644
--- a/compiler/GHC/Tc/Validity.hs
+++ b/compiler/GHC/Tc/Validity.hs
@@ -433,7 +433,7 @@ checkTySynRhs ctxt ty
                         ; expand <- initialExpandMode
                         ; check_pred_ty emptyTidyEnv dflags ctxt expand ty })
          else addErrTcM ( emptyTidyEnv
-                        , TcRnIllegalConstraintSynonymOfKind (tidyKind emptyTidyEnv actual_kind)
+                        , TcRnIllegalConstraintSynonymOfKind (tidyType emptyTidyEnv actual_kind)
                         ) }
 
   | otherwise
@@ -923,7 +923,7 @@ forAllEscapeErr env tvbs theta tau tau_kind
   -- NB: Don't tidy the sigma type since the tvbs were already tidied
   -- previously, and re-tidying them will make the names of type
   -- variables different from tau_kind.
-  = (env, TcRnForAllEscapeError (mkSigmaTy tvbs theta tau) (tidyKind env tau_kind))
+  = (env, TcRnForAllEscapeError (mkSigmaTy tvbs theta tau) (tidyType env tau_kind))
 
 {-
 Note [Type variables escaping through kinds]