Fix assert fail with my $x; sub() {$x}

If $x is not referenced or used in lvalue context elsewhere, then the
constant sub can actually share the same scalar as the enclosing sub’s
pad.  It doesn’t need to copy.  And we don’t in that case, as of
v5.21.5-421-g04472a8.  But we need to make sure the PADTMP flag is
turned off at scope exit if the pad has the only reference to the sub.
(The PADTMP flag has been turned on as of v5.21.5-391-g5543332.)

1 files changed, 1 insertions, 0 deletions

diff --git a/scope.c b/scope.c
index 43e2e03119..8e13071a34 100644
--- a/scope.c
+++ b/scope.c
@@ -1076,6 +1076,7 @@ Perl_leave_scope(pTHX_ I32 base)
                         SvFLAGS(sv) &=~ (SVf_OK|SVf_IVisUV|SVf_UTF8);
                         break;
                     }
+                    SvPADTMP_off(sv);
                     SvPADSTALE_on(sv); /* mark as no longer live */
                 }
                 else {	/* Someone has a claim on this, so abandon it. */