DynFlags: Add inverse of -dno-debug-output

Reviewers: austin

Subscribers: rwbarton, thomie

GHC Trac Issues: #14142

Differential Revision: https://phabricator.haskell.org/D3876

compiler/main/DynFlags.hs

@@ -3089,6 +3089,8 @@ dynamic_flags_deps = [
         (noArg (flip dopt_set Opt_D_dump_json . setJsonLogAction ) )
   , make_ord_flag defGhcFlag "dppr-debug"
         (setDumpFlag Opt_D_ppr_debug)
+  , make_ord_flag defGhcFlag "ddebug-output"
+        (noArg (flip dopt_unset Opt_D_no_debug_output))
   , make_ord_flag defGhcFlag "dno-debug-output"
         (setDumpFlag Opt_D_no_debug_output)
 

docs/users_guide/debugging.rst

@@ -457,6 +457,7 @@ Formatting dumps
 .. ghc-flag:: -dno-debug-output
     :shortdesc: Suppress unsolicited debugging output
     :type: dynamic
+    :reverse: -ddebug-output
     :category:
 
     Suppress any unsolicited debugging output. When GHC has been built