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, 7 insertions, 5 deletions

diff --git a/compiler/prelude/ForeignCall.hs b/compiler/prelude/ForeignCall.hs
index 8411f11e71..ff893ede02 100644
--- a/compiler/prelude/ForeignCall.hs
+++ b/compiler/prelude/ForeignCall.hs
@@ -22,7 +22,7 @@ import FastString
 import Binary
 import Outputable
 import Module
-import BasicTypes ( SourceText )
+import BasicTypes ( SourceText, pprWithSourceText )
 
 import Data.Char
 import Data.Data
@@ -203,14 +203,14 @@ instance Outputable CCallSpec where
       gc_suf | playSafe safety = text "_GC"
              | otherwise       = empty
 
-      ppr_fun (StaticTarget _ fn mPkgId isFun)
+      ppr_fun (StaticTarget st _fn mPkgId isFun)
         = text (if isFun then "__pkg_ccall"
                          else "__pkg_ccall_value")
        <> gc_suf
        <+> (case mPkgId of
             Nothing -> empty
             Just pkgId -> ppr pkgId)
-       <+> pprCLabelString fn
+       <+> (pprWithSourceText st empty)
 
       ppr_fun DynamicTarget
         = text "__dyn_ccall" <> gc_suf <+> text "\"\""
@@ -221,7 +221,7 @@ data Header = Header SourceText FastString
     deriving (Eq, Data)
 
 instance Outputable Header where
-    ppr (Header _ h) = quotes $ ppr h
+    ppr (Header st h) = pprWithSourceText st (doubleQuotes $ ppr h)
 
 -- | A C type, used in CAPI FFI calls
 --
@@ -236,7 +236,9 @@ data CType = CType SourceText -- Note [Pragma source text] in BasicTypes
     deriving (Eq, Data)
 
 instance Outputable CType where
-    ppr (CType _ mh (_,ct)) = hDoc <+> ftext ct
+    ppr (CType stp mh (stct,ct))
+      = pprWithSourceText stp (text "{-# CTYPE") <+> hDoc
+        <+> pprWithSourceText stct (doubleQuotes (ftext ct)) <+> text "#-}"
         where hDoc = case mh of
                      Nothing -> empty
                      Just h -> ppr h