hi haddock: Lex and store haddock docs in interface files

Names appearing in Haddock docstrings are lexed and renamed like any other names
appearing in the AST. We currently rename names irrespective of the namespace,
so both type and constructor names corresponding to an identifier will appear in
the docstring. Haddock will select a given name as the link destination based on
its own heuristics.

This patch also restricts the limitation of `-haddock` being incompatible with
`Opt_KeepRawTokenStream`.

The export and documenation structure is now computed in GHC and serialised in
.hi files. This can be used by haddock to directly generate doc pages without
reparsing or renaming the source. At the moment the operation of haddock
is not modified, that's left to a future patch.

Updates the haddock submodule with the minimum changes needed.

1 files changed, 5 insertions, 1 deletions

diff --git a/compiler/GHC/Driver/Flags.hs b/compiler/GHC/Driver/Flags.hs
index 1d1222fbab..a2ac1b75f4 100644
--- a/compiler/GHC/Driver/Flags.hs
+++ b/compiler/GHC/Driver/Flags.hs
@@ -21,19 +21,23 @@ where
 
 import GHC.Prelude
 import GHC.Utils.Outputable
+import GHC.Utils.Binary
 import GHC.Data.EnumSet as EnumSet
 
 import Control.Monad (guard)
 import Data.List.NonEmpty (NonEmpty(..))
 import Data.Maybe (fromMaybe,mapMaybe)
 
-
 data Language = Haskell98 | Haskell2010 | GHC2021
    deriving (Eq, Enum, Show, Bounded)
 
 instance Outputable Language where
     ppr = text . show
 
+instance Binary Language where
+  put_ bh = put_ bh . fromEnum
+  get bh = toEnum <$> get bh
+
 -- | Debugging flags
 data DumpFlag
 -- See Note [Updating flag description in the User's Guide]