diff --git a/lib/rbs/sorter.rb b/lib/rbs/sorter.rb
index 99ef0cb01..30b9f3a14 100644
--- a/lib/rbs/sorter.rb
+++ b/lib/rbs/sorter.rb
@@ -50,6 +50,7 @@ def sort_decl(decl)
           instance_initialize_methods: [],
           public_instance_methods: [],
           private_instance_methods: [],
+          other_decls: [],
         } #: partitioned
 
         members = decl.members.map { |m| sort_decl m }