diff --git a/lib/rbs/types.rb b/lib/rbs/types.rb
index 5fa045f8a..b6cff3c81 100644
--- a/lib/rbs/types.rb
+++ b/lib/rbs/types.rb
@@ -1407,6 +1407,12 @@ def ==(other)
           other.self_type == self_type
       end
 
+      alias eql? ==
+
+      def hash
+        self.class.hash ^ type.hash ^ required.hash ^ self_type.hash
+      end
+
       def to_json(state = nil)
         {
           type: type,