--- perl-5.6.0/cop.h~	Tue Mar 21 02:26:52 2000
+++ perl-5.6.0/cop.h	Sat Jun 24 18:38:34 2000
@@ -105,13 +105,9 @@
     } STMT_END
 #endif /* USE_THREADS */
 
-#ifdef USE_ITHREADS
-   /* junk in @_ spells trouble when cloning CVs, so don't leave any */
-#  define CLEAR_ARGARRAY()	av_clear(cx->blk_sub.argarray)
-#else
-#  define CLEAR_ARGARRAY()	NOOP
-#endif /* USE_ITHREADS */
-
+/* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
+ * leave any */
+#define CLEAR_ARGARRAY()	av_clear(cx->blk_sub.argarray)
 
 #define POPSUB(cx,sv)							\
     STMT_START {							\
--- perl-5.6.0/t/op/runlevel.t~	Wed Mar  1 09:28:41 2000
+++ perl-5.6.0/t/op/runlevel.t	Sat Jun 24 18:34:44 2000
@@ -349,3 +349,18 @@
 bar
 B 2
 bar
+########
+sub n { 0 }
+sub f { my $x = shift; d(); }
+f(n());
+f();
+
+sub d {
+    my $i = 0; my @a;
+    while (do { { package DB; @a = caller($i++) } } ) {
+        @a = @DB::args;
+        for (@a) { print "$_\n"; $_ = '' }
+    }
+}
+EXPECT
+0