diff --git a/fuzz/src/Main.ml b/fuzz/src/Main.ml
index ac2414529cfbae9f536b42b7f9362757a6200794..10d28dba3df1a5dafb810823fef9652fd51f9f5a 100644
--- a/fuzz/src/Main.ml
+++ b/fuzz/src/Main.ml
@@ -36,9 +36,9 @@ module Settings = struct
      Most tests are shallow anyway. *)
 
   let capacity0, capacity1, capacity2 =
-    interval_ 2 16 (),
-    interval_ 2 4 (),
-    interval_ 2 4 ()
+    closed_interval 2 16 (),
+    closed_interval 2 4 (),
+    closed_interval 2 4 ()
 
   let capacity depth =
     match depth with
@@ -63,7 +63,7 @@ module Settings = struct
      immutable array. *)
 
   let threshold =
-    interval_ 2 32 ()
+    closed_interval 2 32 ()
 
   let () =
     dprintf "  let threshold = %d\n" threshold
@@ -149,7 +149,7 @@ let default =
 let side =
   let generate = Gen.choose [C.front; C.back]
   and print side = !^ (if side = C.front then "front" else "back") in
-  constructible_ generate print
+  easily_constructible generate print
 
 (* -------------------------------------------------------------------------- *)
 
@@ -158,7 +158,7 @@ let side =
 let direction =
   let generate = Gen.choose [C.forward; C.backward]
   and print dir = !^ (if dir = C.forward then "forward" else "backward") in
-  constructible_ generate print
+  easily_constructible generate print
 
 (* -------------------------------------------------------------------------- *)
 
@@ -175,7 +175,7 @@ let element_array =
   let generate = Gen.(array length next)
   and print = Print.(array int) in
   ifpol
-    (constructible_ generate print)
+    (easily_constructible generate print)
     (deconstructible print)
 
 (* -------------------------------------------------------------------------- *)
@@ -212,7 +212,7 @@ let pdraw =
    both included. *)
 
 let itindex length it =
-  interval_ (-1) (length it)
+  closed_interval (-1) (length it)
 
 let eitindex =
   itindex R.E.Iter.length