:art: Allow *abstract final*

diff --git a/ast b/ast
index 68044023ce834c80ff2992487835b91e139a467c..61869ebbd4e91ce188e6298ff1542b1288977e73 160000 (submodule)
--- a/ast
+++ b/ast
@@ -1 +1 @@
-Subproject commit 68044023ce834c80ff2992487835b91e139a467c
+Subproject commit 61869ebbd4e91ce188e6298ff1542b1288977e73