diff --git a/core/CCFloat.ml b/core/CCFloat.ml
index 793544c5..6749913a 100644
--- a/core/CCFloat.ml
+++ b/core/CCFloat.ml
@@ -24,7 +24,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *)
 
 type t = float
-type fpclass = Pervasives.fpclass
+type fpclass = Pervasives.fpclass =
+  | FP_normal
+  | FP_subnormal
+  | FP_zero
+  | FP_infinite
+  | FP_nan
 
 let nan = Pervasives.nan
 
diff --git a/core/CCFloat.mli b/core/CCFloat.mli
index a2419e04..1711385d 100644
--- a/core/CCFloat.mli
+++ b/core/CCFloat.mli
@@ -27,7 +27,12 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 @since NEXT_RELEASE *)
 
 type t = float
-type fpclass
+type fpclass = Pervasives.fpclass =
+  | FP_normal
+  | FP_subnormal
+  | FP_zero
+  | FP_infinite
+  | FP_nan
 
 val nan : t