Add dump-parsed-ast flag and functionality

Summary:
This flag causes a dump of the ParsedSource as an AST in textual form, similar
to the ghc-dump-tree on hackage.

Test Plan: ./validate

Reviewers: mpickering, bgamari, austin

Reviewed By: mpickering

Subscribers: nominolo, thomie

Differential Revision: https://phabricator.haskell.org/D2958

GHC Trac Issues: #11140

1 files changed, 9 insertions, 2 deletions

diff --git a/compiler/main/HscMain.hs b/compiler/main/HscMain.hs
index eb56a54209..b163cbbe21 100644
--- a/compiler/main/HscMain.hs
+++ b/compiler/main/HscMain.hs
@@ -81,6 +81,7 @@ module HscMain
     , showModuleIndex
     ) where
 
+import Data.Data hiding (Fixity, TyCon)
 import Id
 import GHCi.RemoteTypes ( ForeignHValue )
 import ByteCodeGen      ( byteCodeGen, coreExprToBCOs )
@@ -98,6 +99,7 @@ import Module
 import Packages
 import RdrName
 import HsSyn
+import HsDumpAst
 import CoreSyn
 import StringBuffer
 import Parser
@@ -330,6 +332,8 @@ hscParse' mod_summary
             logWarningsReportErrors (getMessages pst dflags)
             liftIO $ dumpIfSet_dyn dflags Opt_D_dump_parsed "Parser" $
                                    ppr rdr_module
+            liftIO $ dumpIfSet_dyn dflags Opt_D_dump_parsed_ast "Parser AST" $
+                                   text (showAstData NoBlankSrcSpan rdr_module)
             liftIO $ dumpIfSet_dyn dflags Opt_D_source_stats "Source Statistics" $
                                    ppSourceStats False rdr_module
 
@@ -1662,10 +1666,11 @@ hscParseIdentifier :: HscEnv -> String -> IO (Located RdrName)
 hscParseIdentifier hsc_env str =
     runInteractiveHsc hsc_env $ hscParseThing parseIdentifier str
 
-hscParseThing :: (Outputable thing) => Lexer.P thing -> String -> Hsc thing
+hscParseThing :: (Outputable thing, Data thing)
+              => Lexer.P thing -> String -> Hsc thing
 hscParseThing = hscParseThingWithLocation "<interactive>" 1
 
-hscParseThingWithLocation :: (Outputable thing) => String -> Int
+hscParseThingWithLocation :: (Outputable thing, Data thing) => String -> Int
                           -> Lexer.P thing -> String -> Hsc thing
 hscParseThingWithLocation source linenumber parser str
   = withTiming getDynFlags
@@ -1684,6 +1689,8 @@ hscParseThingWithLocation source linenumber parser str
         POk pst thing -> do
             logWarningsReportErrors (getMessages pst dflags)
             liftIO $ dumpIfSet_dyn dflags Opt_D_dump_parsed "Parser" (ppr thing)
+            liftIO $ dumpIfSet_dyn dflags Opt_D_dump_parsed_ast "Parser AST" $
+                                   text $ showAstData NoBlankSrcSpan thing
             return thing