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, 6 insertions, 33 deletions

diff --git a/compiler/GHC/Core/TyCo/Rep.hs b/compiler/GHC/Core/TyCo/Rep.hs
index bb7280dd0d..31c8813e10 100644
--- a/compiler/GHC/Core/TyCo/Rep.hs
+++ b/compiler/GHC/Core/TyCo/Rep.hs
@@ -713,10 +713,8 @@ data TyCoBinder
 instance Outputable TyCoBinder where
   ppr (Anon af ty) = ppr af <+> ppr ty
   ppr (Named (Bndr v Required))  = ppr v
-  -- See Note [Explicit Case Statement for Specificity]
-  ppr (Named (Bndr v (Invisible spec))) = case spec of
-    SpecifiedSpec -> char '@' <> ppr v
-    InferredSpec  -> braces (ppr v)
+  ppr (Named (Bndr v Specified)) = char '@' <> ppr v
+  ppr (Named (Bndr v Inferred))  = braces (ppr v)
 
 
 -- | 'TyBinder' is like 'TyCoBinder', but there can only be 'TyVarBinder'
diff --git a/compiler/GHC/Core/TyCo/Tidy.hs b/compiler/GHC/Core/TyCo/Tidy.hs
index 96cbed6ade..97d3adf8e0 100644
--- a/compiler/GHC/Core/TyCo/Tidy.hs
+++ b/compiler/GHC/Core/TyCo/Tidy.hs
@@ -8,12 +8,10 @@ module GHC.Core.TyCo.Tidy
         -- * Tidying type related things up for printing
         tidyType,      tidyTypes,
         tidyOpenType,  tidyOpenTypes,
-        tidyOpenKind,
         tidyVarBndr, tidyVarBndrs, tidyFreeTyCoVars, avoidNameClashes,
         tidyOpenTyCoVar, tidyOpenTyCoVars,
         tidyTyCoVarOcc,
         tidyTopType,
-        tidyKind,
         tidyCo, tidyCos,
         tidyTyCoVarBinder, tidyTyCoVarBinders
   ) where
@@ -215,13 +213,6 @@ tidyTopType :: Type -> Type
 tidyTopType ty = tidyType emptyTidyEnv ty
 
 ---------------
-tidyOpenKind :: TidyEnv -> Kind -> (TidyEnv, Kind)
-tidyOpenKind = tidyOpenType
-
-tidyKind :: TidyEnv -> Kind -> Kind
-tidyKind = tidyType
-
-----------------
 
 -- | Tidy a Coercion
 --
diff --git a/compiler/GHC/Core/TyCon.hs b/compiler/GHC/Core/TyCon.hs
index 24807945cc..e267932e14 100644
--- a/compiler/GHC/Core/TyCon.hs
+++ b/compiler/GHC/Core/TyCon.hs
@@ -680,10 +680,8 @@ instance OutputableBndr tv => Outputable (VarBndr tv TyConBndrVis) where
       ppr_bi (AnonTCB VisArg)     = text "anon-vis"
       ppr_bi (AnonTCB InvisArg)   = text "anon-invis"
       ppr_bi (NamedTCB Required)  = text "req"
-      -- See Note [Explicit Case Statement for Specificity]
-      ppr_bi (NamedTCB (Invisible spec)) = case spec of
-        SpecifiedSpec -> text "spec"
-        InferredSpec  -> text "inf"
+      ppr_bi (NamedTCB Specified) = text "spec"
+      ppr_bi (NamedTCB Inferred)  = text "inf"
 
 instance Binary TyConBndrVis where
   put_ bh (AnonTCB af)   = do { putByte bh 0; put_ bh af }
diff --git a/compiler/GHC/Core/Type.hs b/compiler/GHC/Core/Type.hs
index cf671657b0..85cc635791 100644
--- a/compiler/GHC/Core/Type.hs
+++ b/compiler/GHC/Core/Type.hs
@@ -222,12 +222,10 @@ module GHC.Core.Type (
         -- * Tidying type related things up for printing
         tidyType,      tidyTypes,
         tidyOpenType,  tidyOpenTypes,
-        tidyOpenKind,
         tidyVarBndr, tidyVarBndrs, tidyFreeTyCoVars,
         tidyOpenTyCoVar, tidyOpenTyCoVars,
         tidyTyCoVarOcc,
         tidyTopType,
-        tidyKind,
         tidyTyCoVarBinder, tidyTyCoVarBinders,
 
         -- * Kinds
@@ -3541,22 +3539,10 @@ tyConAppNeedsKindSig spec_inj_pos tc n_args
         _              -> emptyFV
 
     source_of_injectivity Required  = True
-    -- See Note [Explicit Case Statement for Specificity]
-    source_of_injectivity (Invisible spec) = case spec of
-      SpecifiedSpec -> spec_inj_pos
-      InferredSpec  -> False
+    source_of_injectivity Specified = spec_inj_pos
+    source_of_injectivity Inferred  = False
 
 {-
-Note [Explicit Case Statement for Specificity]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-When pattern matching against an `ArgFlag`, you should not pattern match against
-the pattern synonyms 'Specified' or 'Inferred', as this results in a
-non-exhaustive pattern match warning.
-Instead, pattern match against 'Invisible spec' and do another case analysis on
-this specificity argument.
-The issue has been fixed in GHC 8.10 (ticket #17876). This hack can thus be
-dropped once version 8.10 is used as the minimum version for building GHC.
-
 Note [When does a tycon application need an explicit kind signature?]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 There are a couple of places in GHC where we convert Core Types into forms that