tag_equal must be physical equality

src/util/hashweak.ml

@@ -76,11 +76,9 @@ let dummy_tag = {
   tag_tag = -1;
 }
 
-let tag_hash k = assert (k != dummy_tag); k.tag_tag
-
-let tag_equal k1 k2 = k1.tag_tag = k2.tag_tag
+let tag_equal = (==)
 
-let tag_compare k1 k2 = Pervasives.compare k1.tag_tag k2.tag_tag
+let tag_hash k = assert (k != dummy_tag); k.tag_tag
 
 module type Weakey =
 sig

src/util/hashweak.mli

@@ -25,11 +25,9 @@ val dummy_tag : tag
 
 val create_tag : int -> tag
 
-val tag_hash : tag -> int
-
 val tag_equal : tag -> tag -> bool
 
-val tag_compare : tag -> tag -> int
+val tag_hash : tag -> int
 
 module type S = sig