Fix SEGVs when cloning a typeglob that has been undefined. (RT #64954)

1 files changed, 6 insertions, 1 deletions

diff --git a/t/op/threads.t b/t/op/threads.t
index 814b59550f..c8ed34a7a1 100644
--- a/t/op/threads.t
+++ b/t/op/threads.t
@@ -16,7 +16,7 @@ BEGIN {
        exit 0;
      }
 
-     plan(13);
+     plan(14);
 }
 
 use strict;
@@ -185,5 +185,10 @@ threads->new(\&safe_re)->join();
 # tests in threads don't get counted, so
 curr_test(curr_test() + 1);
 
+# This used to crash in 5.10.0 [perl #64954]
+
+undef *a;
+threads->new(sub {})->join;
+pass("undefing a typeglob doesn't cause a crash during cloning");
 
 # EOF