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, 58 insertions, 45 deletions

diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index 6800fab57e..14a7cb2ffa 100644
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -114,7 +114,7 @@ import DynFlags
 import SrcLoc
 import Module
 import BasicTypes     ( InlineSpec(..), RuleMatchInfo(..), FractionalLit(..),
-                        SourceText )
+                        SourceText(..) )
 
 -- compiler/parser
 import Ctype
@@ -1126,7 +1126,7 @@ rulePrag :: Action
 rulePrag span buf len = do
   setExts (.|. xbit InRulePragBit)
   let !src = lexemeToString buf len
-  return (L span (ITrules_prag src))
+  return (L span (ITrules_prag (SourceText src)))
 
 endPrag :: Action
 endPrag span _buf _len = do
@@ -1260,13 +1260,13 @@ sym con span buf len =
     !fs = lexemeToFastString buf len
 
 -- Variations on the integral numeric literal.
-tok_integral :: (String -> Integer -> Token)
+tok_integral :: (SourceText -> Integer -> Token)
              -> (Integer -> Integer)
              -> Int -> Int
              -> (Integer, (Char -> Int))
              -> Action
 tok_integral itint transint transbuf translen (radix,char_to_int) span buf len
- = return $ L span $ itint (lexemeToString buf len)
+ = return $ L span $ itint (SourceText $ lexemeToString buf len)
        $! transint $ parseUnsignedInteger
        (offsetBytes transbuf buf) (subtract translen len) radix char_to_int
 
@@ -1452,8 +1452,8 @@ lex_string_tok span buf _len = do
   (AI end bufEnd) <- getInput
   let
     tok' = case tok of
-            ITprimstring _ bs -> ITprimstring src bs
-            ITstring _ s -> ITstring src s
+            ITprimstring _ bs -> ITprimstring (SourceText src) bs
+            ITstring _ s -> ITstring (SourceText src) s
             _ -> panic "lex_string_tok"
     src = lexemeToString buf (cur bufEnd - cur buf)
   return (L (mkRealSrcSpan (realSrcSpanStart span) end) tok')
@@ -1476,11 +1476,13 @@ lex_string s = do
                    if any (> '\xFF') s
                     then failMsgP "primitive string literal must contain only characters <= \'\\xFF\'"
                     else let bs = unsafeMkByteString (reverse s)
-                         in return (ITprimstring "" bs)
+                         in return (ITprimstring (SourceText (reverse s)) bs)
               _other ->
-                return (ITstring "" (mkFastString (reverse s)))
+                return (ITstring (SourceText (reverse s))
+                                 (mkFastString (reverse s)))
           else
-                return (ITstring "" (mkFastString (reverse s)))
+                return (ITstring (SourceText (reverse s))
+                                 (mkFastString (reverse s)))
 
     Just ('\\',i)
         | Just ('&',i) <- next -> do
@@ -1555,14 +1557,16 @@ finish_char_tok buf loc ch  -- We've already seen the closing quote
         i@(AI end bufEnd) <- getInput
         let src = lexemeToString buf (cur bufEnd - cur buf)
         if magicHash then do
-                case alexGetChar' i of
-                        Just ('#',i@(AI end _)) -> do
-                          setInput i
-                          return (L (mkRealSrcSpan loc end) (ITprimchar src ch))
-                        _other ->
-                          return (L (mkRealSrcSpan loc end) (ITchar src ch))
+            case alexGetChar' i of
+              Just ('#',i@(AI end _)) -> do
+                setInput i
+                return (L (mkRealSrcSpan loc end)
+                          (ITprimchar (SourceText src) ch))
+              _other ->
+                return (L (mkRealSrcSpan loc end)
+                          (ITchar (SourceText src) ch))
             else do
-                   return (L (mkRealSrcSpan loc end) (ITchar src ch))
+              return (L (mkRealSrcSpan loc end) (ITchar (SourceText src) ch))
 
 isAny :: Char -> Bool
 isAny c | c > '\x7f' = isPrint c
@@ -2713,37 +2717,46 @@ ignoredPrags = Map.fromList (map ignored pragmas)
                      pragmas = options_pragmas ++ ["cfiles", "contract"]
 
 oneWordPrags = Map.fromList([
-           ("rules", rulePrag),
-           ("inline", strtoken (\s -> (ITinline_prag s Inline FunLike))),
-           ("inlinable", strtoken (\s -> (ITinline_prag s Inlinable FunLike))),
-           ("inlineable", strtoken (\s -> (ITinline_prag s Inlinable FunLike))),
-                                          -- Spelling variant
-           ("notinline", strtoken (\s -> (ITinline_prag s NoInline FunLike))),
-           ("specialize", strtoken (\s -> ITspec_prag s)),
-           ("source", strtoken (\s -> ITsource_prag s)),
-           ("warning", strtoken (\s -> ITwarning_prag s)),
-           ("deprecated", strtoken (\s -> ITdeprecated_prag s)),
-           ("scc", strtoken (\s -> ITscc_prag s)),
-           ("generated", strtoken (\s -> ITgenerated_prag s)),
-           ("core", strtoken (\s -> ITcore_prag s)),
-           ("unpack", strtoken (\s -> ITunpack_prag s)),
-           ("nounpack", strtoken (\s -> ITnounpack_prag s)),
-           ("ann", strtoken (\s -> ITann_prag s)),
-           ("vectorize", strtoken (\s -> ITvect_prag s)),
-           ("novectorize", strtoken (\s -> ITnovect_prag s)),
-           ("minimal", strtoken (\s -> ITminimal_prag s)),
-           ("overlaps", strtoken (\s -> IToverlaps_prag s)),
-           ("overlappable", strtoken (\s -> IToverlappable_prag s)),
-           ("overlapping", strtoken (\s -> IToverlapping_prag s)),
-           ("incoherent", strtoken (\s -> ITincoherent_prag s)),
-           ("ctype", strtoken (\s -> ITctype s))])
+     ("rules", rulePrag),
+     ("inline",
+         strtoken (\s -> (ITinline_prag (SourceText s) Inline FunLike))),
+     ("inlinable",
+         strtoken (\s -> (ITinline_prag (SourceText s) Inlinable FunLike))),
+     ("inlineable",
+         strtoken (\s -> (ITinline_prag (SourceText s) Inlinable FunLike))),
+                                    -- Spelling variant
+     ("notinline",
+         strtoken (\s -> (ITinline_prag (SourceText s) NoInline FunLike))),
+     ("specialize", strtoken (\s -> ITspec_prag (SourceText s))),
+     ("source", strtoken (\s -> ITsource_prag (SourceText s))),
+     ("warning", strtoken (\s -> ITwarning_prag (SourceText s))),
+     ("deprecated", strtoken (\s -> ITdeprecated_prag (SourceText s))),
+     ("scc", strtoken (\s -> ITscc_prag (SourceText s))),
+     ("generated", strtoken (\s -> ITgenerated_prag (SourceText s))),
+     ("core", strtoken (\s -> ITcore_prag (SourceText s))),
+     ("unpack", strtoken (\s -> ITunpack_prag (SourceText s))),
+     ("nounpack", strtoken (\s -> ITnounpack_prag (SourceText s))),
+     ("ann", strtoken (\s -> ITann_prag (SourceText s))),
+     ("vectorize", strtoken (\s -> ITvect_prag (SourceText s))),
+     ("novectorize", strtoken (\s -> ITnovect_prag (SourceText s))),
+     ("minimal", strtoken (\s -> ITminimal_prag (SourceText s))),
+     ("overlaps", strtoken (\s -> IToverlaps_prag (SourceText s))),
+     ("overlappable", strtoken (\s -> IToverlappable_prag (SourceText s))),
+     ("overlapping", strtoken (\s -> IToverlapping_prag (SourceText s))),
+     ("incoherent", strtoken (\s -> ITincoherent_prag (SourceText s))),
+     ("ctype", strtoken (\s -> ITctype (SourceText s)))])
 
 twoWordPrags = Map.fromList([
-     ("inline conlike", strtoken (\s -> (ITinline_prag s Inline ConLike))),
-     ("notinline conlike", strtoken (\s -> (ITinline_prag s NoInline ConLike))),
-     ("specialize inline", strtoken (\s -> (ITspec_inline_prag s True))),
-     ("specialize notinline", strtoken (\s -> (ITspec_inline_prag s False))),
-     ("vectorize scalar", strtoken (\s -> ITvect_scalar_prag s))])
+     ("inline conlike",
+         strtoken (\s -> (ITinline_prag (SourceText s) Inline ConLike))),
+     ("notinline conlike",
+         strtoken (\s -> (ITinline_prag (SourceText s) NoInline ConLike))),
+     ("specialize inline",
+         strtoken (\s -> (ITspec_inline_prag (SourceText s) True))),
+     ("specialize notinline",
+         strtoken (\s -> (ITspec_inline_prag (SourceText s) False))),
+     ("vectorize scalar",
+         strtoken (\s -> ITvect_scalar_prag (SourceText s)))])
 
 dispatch_pragmas :: Map String Action -> Action
 dispatch_pragmas prags span buf len = case Map.lookup (clean_pragma (lexemeToString buf len)) prags of