Trees That Grow refactor for `ConPat` and `CoPat`

- `ConPat{In,Out}` -> `ConPat`

- `CoPat` -> `XPat (CoPat ..)`

Note that `GHC.HS.*` still uses `HsWrap`, but only when `p ~ GhcTc`.
After this change, moving the type family instances out of `GHC.HS.*` is
sufficient to break the cycle.

Add XCollectPat class to decide how binders are collected from XXPat based on the pass.

Previously we did this with IsPass, but that doesn't work for Haddock's
DocNameI, and the constraint doesn't express what actual distinction is being
made. Perhaps a class for collecting binders more generally is in order, but we
haven't attempted this yet.

Pure refactor of code around ConPat

 - InPat/OutPat synonyms removed

 - rename several identifiers

 - redundant constraints removed

 - move extension field in ConPat to be first

 - make ConPat use record syntax more consistently

Fix T6145 (ConPatIn became ConPat)

Add comments from SPJ.

Add comment about haddock's use of CollectPass.

Updates haddock submodule.

1 files changed, 15 insertions, 8 deletions

diff --git a/compiler/GHC/Rename/Pat.hs b/compiler/GHC/Rename/Pat.hs
index d8f55ccc1f..8e6747550e 100644
--- a/compiler/GHC/Rename/Pat.hs
+++ b/compiler/GHC/Rename/Pat.hs
@@ -468,14 +468,14 @@ rnPatAndThen mk p@(ViewPat x expr pat)
        -- ; return (ViewPat expr' pat' ty) }
        ; return (ViewPat x expr' pat') }
 
-rnPatAndThen mk (ConPatIn con stuff)
+rnPatAndThen mk (ConPat NoExtField con args)
    -- rnConPatAndThen takes care of reconstructing the pattern
    -- The pattern for the empty list needs to be replaced by an empty explicit list pattern when overloaded lists is turned on.
   = case unLoc con == nameRdrName (dataConName nilDataCon) of
       True    -> do { ol_flag <- liftCps $ xoptM LangExt.OverloadedLists
                     ; if ol_flag then rnPatAndThen mk (ListPat noExtField [])
-                                 else rnConPatAndThen mk con stuff}
-      False   -> rnConPatAndThen mk con stuff
+                                 else rnConPatAndThen mk con args}
+      False   -> rnConPatAndThen mk con args
 
 rnPatAndThen mk (ListPat _ pats)
   = do { opt_OverloadedLists <- liftCps $ xoptM LangExt.OverloadedLists
@@ -505,9 +505,6 @@ rnPatAndThen mk (SplicePat _ splice)
            Left  not_yet_renamed -> rnPatAndThen mk not_yet_renamed
            Right already_renamed -> return already_renamed }
 
-rnPatAndThen _ pat = pprPanic "rnLPatAndThen" (ppr pat)
-
-
 --------------------
 rnConPatAndThen :: NameMaker
                 -> Located RdrName    -- the constructor
@@ -517,7 +514,12 @@ rnConPatAndThen :: NameMaker
 rnConPatAndThen mk con (PrefixCon pats)
   = do  { con' <- lookupConCps con
         ; pats' <- rnLPatsAndThen mk pats
-        ; return (ConPatIn con' (PrefixCon pats')) }
+        ; return $ ConPat
+            { pat_con_ext = noExtField
+            , pat_con = con'
+            , pat_args = PrefixCon pats'
+            }
+        }
 
 rnConPatAndThen mk con (InfixCon pat1 pat2)
   = do  { con' <- lookupConCps con
@@ -529,7 +531,12 @@ rnConPatAndThen mk con (InfixCon pat1 pat2)
 rnConPatAndThen mk con (RecCon rpats)
   = do  { con' <- lookupConCps con
         ; rpats' <- rnHsRecPatsAndThen mk con' rpats
-        ; return (ConPatIn con' (RecCon rpats')) }
+        ; return $ ConPat
+            { pat_con_ext = noExtField
+            , pat_con = con'
+            , pat_args = RecCon rpats'
+            }
+        }
 
 checkUnusedRecordWildcardCps :: SrcSpan -> Maybe [Name] -> CpsRn ()
 checkUnusedRecordWildcardCps loc dotdot_names =