attributes.xs: Don’t emit const warning for anons

The intent was to emit the warning for any cases other than custom
attributes on anonymous subs.  I did that by checking to see whether
we had a closure prototype, warning otherwise.  But anonymous subs
that are not closures are not closure prototypes.  So we need to
check CvANON instead.

1 files changed, 3 insertions, 1 deletions

diff --git a/t/op/attrs.t b/t/op/attrs.t
index f8515fb3d0..b93ed74eb9 100644
--- a/t/op/attrs.t
+++ b/t/op/attrs.t
@@ -407,7 +407,9 @@ is $ProtoTest::Proto, '$', 'prototypes are visible in attr handlers';
         attributes->import(shift, shift, lc shift) if $_[2]; ()
     }
     $_ = 32487;
-    my $sub = sub : Const { $_ };
+    my $sub = eval '+sub : Const { $_ }';
+    ::is $w, '',
+     'no warning for :const applied to closure protosub via attributes.pm';
     undef $_;
     ::is &$sub, 32487,
         'applying const attr via attributes.pm';