parse-fallback-fix.patch

diff --git a/src/core/Grammar.pm b/src/core/Grammar.pm
index 514b81d2d..b80ca248c 100644
--- a/src/core/Grammar.pm
+++ b/src/core/Grammar.pm
@@ -28,9 +28,11 @@ my class Grammar is Match {
                   ),
                   $match := ($cursor := $cursor.'!cursor_next'()).MATCH
                 ),
-                $match || $grammar.?SETFAIL($match, :$filename)
+                $match || nqp::if(nqp::can($grammar, 'SETFAIL'),
+                                  $grammar.SETFAIL($match, :$filename), Nil)
               ),
-              $grammar.?SETFAIL($cursor, :$filename)
+              nqp::if(nqp::can($grammar, 'SETFAIL'),
+                      $grammar.SETFAIL($cursor, :$filename), Nil)
             )
           )
         )