Add HsSyn prettyprinter tests

Summary:
Add prettyprinter tests, which take a file, parse it, pretty print it,
re-parse the pretty printed version and then compare the original and
new ASTs (ignoring locations)

Updates haddock submodule to match the AST changes.

There are three issues outstanding

1. Extra parens around a context are not reproduced. This will require an
   AST change and will be done in a separate patch.

2. Currently if an `HsTickPragma` is found, this is not pretty-printed,
   to prevent noise in the output.

   I am not sure what the desired behaviour in this case is, so have left
   it as before. Test Ppr047 is marked as expected fail for this.

3. Apart from in a context, the ParsedSource AST keeps all the parens from
   the original source.  Something is happening in the renamer to remove the
   parens around visible type application, causing T12530 to fail, as the
   dumped splice decl is after the renamer.

   This needs to be fixed by keeping the parens, but I do not know where they
   are being removed.  I have amended the test to pass, by removing the parens
   in the expected output.

Test Plan: ./validate

Reviewers: goldfire, mpickering, simonpj, bgamari, austin

Reviewed By: simonpj, bgamari

Subscribers: simonpj, goldfire, thomie, mpickering

Differential Revision: https://phabricator.haskell.org/D2752

GHC Trac Issues: #3384

1 files changed, 5 insertions, 4 deletions

diff --git a/compiler/rename/RnEnv.hs b/compiler/rename/RnEnv.hs
index 801bc2724f..f8969a8e13 100644
--- a/compiler/rename/RnEnv.hs
+++ b/compiler/rename/RnEnv.hs
@@ -75,7 +75,8 @@ import DataCon
 import TyCon
 import PrelNames        ( mkUnboundName, isUnboundName, rOOT_MAIN, forall_tv_RDR )
 import ErrUtils         ( MsgDoc )
-import BasicTypes       ( Fixity(..), FixityDirection(..), minPrecedence, defaultFixity )
+import BasicTypes       ( Fixity(..), FixityDirection(..), minPrecedence,
+                          defaultFixity, pprWarningTxtForMsg, SourceText(..) )
 import SrcLoc
 import Outputable
 import Util
@@ -1072,7 +1073,7 @@ warnIfDeprecated gre@(GRE { gre_name = name, gre_imp = iss })
                     <+> pprNonVarNameSpace (occNameSpace occ)
                     <+> quotes (ppr occ)
                   , parens imp_msg <> colon ]
-            , ppr txt ]
+            , pprWarningTxtForMsg txt ]
       where
         imp_mod  = importSpecModule imp_spec
         imp_msg  = text "imported from" <+> ppr imp_mod <> extra
@@ -1438,7 +1439,7 @@ lookupFixityRn_help' :: Name
                      -> RnM (Bool, Fixity)
 lookupFixityRn_help' name occ
   | isUnboundName name
-  = return (False, Fixity (show minPrecedence) minPrecedence InfixL)
+  = return (False, Fixity NoSourceText minPrecedence InfixL)
     -- Minimise errors from ubound names; eg
     --    a>0 `foo` b>0
     -- where 'foo' is not in scope, should not give an error (Trac #7937)
@@ -1517,7 +1518,7 @@ lookupFieldFixityRn (Ambiguous   (L _ rdr) _) = get_ambiguous_fixity rdr
         [] -> panic "get_ambiguous_fixity: no candidates for a given RdrName"
         [ (_, fix):_ ] -> return fix
         ambigs -> addErr (ambiguous_fixity_err rdr_name ambigs)
-                  >> return (Fixity(show minPrecedence) minPrecedence InfixL)
+                  >> return (Fixity NoSourceText minPrecedence InfixL)
 
     lookup_gre_fixity gre = lookupFixityRn' (gre_name gre) (greOccName gre)