Allow :isa in class declaration without a block

Using class attributes in the unit class syntax was a syntax error. This change makes the following two lines equivalent:

class B :isa(A) ;
class B :isa(A) { }

Addresses GH issue #20888.

1 files changed, 10 insertions, 0 deletions

diff --git a/t/class/inherit.t b/t/class/inherit.t
index 03b2199683..9fd314b9f9 100644
--- a/t/class/inherit.t
+++ b/t/class/inherit.t
@@ -71,4 +71,14 @@ no warnings 'experimental::class';
     is($obj->x, "X", 'Constructor params passed through to superclass');
 }
 
+{
+    class Test4A { }
+
+    class Test4B :isa(Test4A);
+
+    package main;
+    my $obj = Test4B->new;
+    ok($obj isa Test4A, 'Unit class syntax allows :isa');
+}
+
 done_testing;