Udate hsSyn AST to use Trees that Growwip/new-tree-one-param-2

Summary:
See https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow

This commit prepares the ground for a full extensible AST, by replacing the type
parameter for the hsSyn data types with a set of indices into type families,

    data GhcPs -- ^ Index for GHC parser output
    data GhcRn -- ^ Index for GHC renamer output
    data GhcTc -- ^ Index for GHC typechecker output

These are now used instead of `RdrName`, `Name` and `Id`/`TcId`/`Var`

Where the original name type is required in a polymorphic context, this is
accessible via the IdP type family, defined as

    type family IdP p
    type instance IdP GhcPs = RdrName
    type instance IdP GhcRn = Name
    type instance IdP GhcTc = Id

These types are declared in the new 'hsSyn/HsExtension.hs' module.

To gain a better understanding of the extension mechanism, it has been applied
to `HsLit` only, also replacing the `SourceText` fields in them with extension
types.

To preserve extension generality, a type class is introduced to capture the
`SourceText` interface, which must be honoured by all of the extension points
which originally had a `SourceText`.  The class is defined as

    class HasSourceText a where
      -- Provide setters to mimic existing constructors
      noSourceText  :: a
      sourceText    :: String -> a

      setSourceText :: SourceText -> a
      getSourceText :: a -> SourceText

And the constraint is captured in `SourceTextX`, which is a constraint type
listing all the extension points that make use of the class.

Updating Haddock submodule to match.

Test Plan: ./validate

Reviewers: simonpj, shayan-najd, goldfire, austin, bgamari

Subscribers: rwbarton, thomie, mpickering

Differential Revision: https://phabricator.haskell.org/D3609

1 files changed, 4 insertions, 4 deletions

diff --git a/compiler/main/GHC.hs b/compiler/main/GHC.hs
index 48767bf12d..af00dab4f2 100644
--- a/compiler/main/GHC.hs
+++ b/compiler/main/GHC.hs
@@ -831,10 +831,10 @@ instance TypecheckedMod DesugaredModule where
 instance DesugaredMod DesugaredModule where
   coreModule m = dm_core_module m
 
-type ParsedSource      = Located (HsModule RdrName)
-type RenamedSource     = (HsGroup Name, [LImportDecl Name], Maybe [LIE Name],
+type ParsedSource      = Located (HsModule GhcPs)
+type RenamedSource     = (HsGroup GhcRn, [LImportDecl GhcRn], Maybe [LIE GhcRn],
                           Maybe LHsDocString)
-type TypecheckedSource = LHsBinds Id
+type TypecheckedSource = LHsBinds GhcTc
 
 -- NOTE:
 --   - things that aren't in the output of the typechecker right now:
@@ -1481,7 +1481,7 @@ lookupName name =
 parser :: String         -- ^ Haskell module source text (full Unicode is supported)
        -> DynFlags       -- ^ the flags
        -> FilePath       -- ^ the filename (for source locations)
-       -> (WarningMessages, Either ErrorMessages (Located (HsModule RdrName)))
+       -> (WarningMessages, Either ErrorMessages (Located (HsModule GhcPs)))
 
 parser str dflags filename =
    let