1 files changed, 3 insertions, 0 deletions
diff --git a/op.c b/op.c
index 373822a349..c6f228b2e0 100644
--- a/op.c
+++ b/op.c
@@ -9847,9 +9847,12 @@ Perl_newATTRSUB_x(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs,
 	   Also, we may be called from load_module at run time, so
 	   PL_curstash (which sets CvSTASH) may not point to the stash the
 	   sub is stored in.  */
+	/* XXX This optimization is currently disabled for packages other
+	       than main, since there was too much CPAN breakage.  */
 	const I32 flags =
 	   ec ? GV_NOADD_NOINIT
 	      :   (IN_PERL_RUNTIME && PL_curstash != CopSTASH(PL_curcop))
+	       || PL_curstash != PL_defstash
 	       || memchr(name, ':', namlen) || memchr(name, '\'', namlen)
 		    ? gv_fetch_flags
 		    : GV_ADDMULTI | GV_NOINIT | GV_NOTQUAL;