Fix @{*ISA} autovivification

It was not attaching magic to the array, preventing subsequent changes
to the array from updating isa caches.

1 files changed, 8 insertions, 1 deletions

diff --git a/t/mro/basic.t b/t/mro/basic.t
index e1a4dbfddb..188159e2fc 100644
--- a/t/mro/basic.t
+++ b/t/mro/basic.t
@@ -3,7 +3,7 @@
 use strict;
 use warnings;
 
-BEGIN { require q(./test.pl); } plan(tests => 53);
+BEGIN { require q(./test.pl); } plan(tests => 54);
 
 require mro;
 
@@ -338,3 +338,10 @@ is(eval { MRO_N->testfunc() }, 123);
     ok !Gwythaint->isa("Fantastic::Creature"),
        'obliterating @ISA via glob assignment';
 }
+
+{
+    # Autovivifying @ISA via @{*ISA}
+    undef *fednu::ISA;
+    @{*fednu::ISA} = "pyfg";
+    ok +fednu->isa("pyfg"), 'autovivifying @ISA via *{@ISA}';
+}