1 files changed, 10 insertions, 1 deletions
diff --git a/lib/syntax/tree.mli b/lib/syntax/tree.mli
index 8ce577e..9ed442b 100644
--- a/lib/syntax/tree.mli
+++ b/lib/syntax/tree.mli
@@ -43,9 +43,18 @@ module Ast : sig
   [@@deriving eq, show]
 end
 
+(** Extend the default Expression module with an eq operator *)
+module Expression : sig
+  include S.Expression with type t' = S.pos Ast.expression
+
+  val eq : (S.pos -> S.pos -> bool) -> t' -> t' -> bool
+  val hash : (S.pos -> int) -> t' -> int
+  val exists : f:(t' -> bool) -> t' -> bool
+end
+
 include
   S.Analyzer
-    with type Expression.t' = S.pos Ast.expression
+    with module Expression := Expression
      and type Instruction.t' = S.pos Ast.statement
      and type Location.t = S.pos * S.pos Ast.statement list
      and type context = unit