close($undef) should not croak_no_modify

Commit ac53db4c3f7e fixed bug #31767 (open $1 not dying), but put the
SvREADONLY check in the wrong spot, causing this bug:

$ perl -lwe 'no warnings "once"; close $x; close $+'
Name "main::x" used only once: possible typo at -e line 1.
Use of uninitialized value $x in ref-to-glob cast at -e line 1.
Modification of a read-only value attempted at -e line 1.

It shouldn’t be dying if I’m not trying to modifying it.

1 files changed, 2 insertions, 2 deletions

diff --git a/pp.c b/pp.c
index e60f7dba0e..865001b9a4 100644
--- a/pp.c
+++ b/pp.c
@@ -169,10 +169,10 @@ PP(pp_rv2gv)
 		/* If this is a 'my' scalar and flag is set then vivify
 		 * NI-S 1999/05/07
 		 */
-		if (SvREADONLY(sv))
-		    Perl_croak_no_modify(aTHX);
 		if (PL_op->op_private & OPpDEREF) {
 		    GV *gv;
+		    if (SvREADONLY(sv))
+			Perl_croak_no_modify(aTHX);
 		    if (cUNOP->op_targ) {
 			STRLEN len;
 			SV * const namesv = PAD_SV(cUNOP->op_targ);