[perl #96326] *{$io} should not be semi-defined

gv_efullname4 produces undef if the GV points to no stash, instead of
using __ANON__, as it does when the stash has no name.

Instead of going through hoops to try and work around it elsewhere, fix
gv_efullname4.

This means that

   $x = *$io;
   $x .= "whate’er";

no longer produces an uninitialized warning.  (The warning was rather
strange, as defined() returned true.)

This commit also gives the glob the name $__ANONIO__ (yes, with a dol-
lar sign).  It may seem a little strange, but there is precedent in
other autovivified globs, such as those open() produces when it cannot
determine the variable name (e.g, open $t->{fh}).

1 files changed, 1 insertions, 1 deletions

diff --git a/pp.c b/pp.c
index 7114f89bdb..5d5b6aee58 100644
--- a/pp.c
+++ b/pp.c
@@ -165,7 +165,7 @@ S_rv2gv(pTHX_ SV *sv, const bool vivify_sv, const bool strict,
 	sv = SvRV(sv);
 	if (SvTYPE(sv) == SVt_PVIO) {
 	    GV * const gv = MUTABLE_GV(sv_newmortal());
-	    gv_init(gv, 0, "", 0, 0);
+	    gv_init(gv, 0, "$__ANONIO__", 11, 0);
 	    GvIOp(gv) = MUTABLE_IO(sv);
 	    SvREFCNT_inc_void_NN(sv);
 	    sv = MUTABLE_SV(gv);