diff --git a/infer/src/checkers/Source.ml b/infer/src/checkers/Source.ml
index ac401d039..831458765 100644
--- a/infer/src/checkers/Source.ml
+++ b/infer/src/checkers/Source.ml
@@ -21,7 +21,7 @@ module type S = sig
 end
 
 module Dummy = struct
-  type t = unit
+  type t = unit [@@deriving compare]
 
   let call_site _ = CallSite.dummy
 
@@ -29,8 +29,6 @@ module Dummy = struct
 
   let make kind _ = kind
 
-  let compare = Pervasives.compare
-
   let pp _ () = ()
 
   let is_footprint _ = false