fix rescript-lang#3455

Author: bobzhang

jscomp/runtime/caml_obj.ml

@@ -232,6 +232,8 @@ let rec caml_compare (a : Caml_obj_extern.t) (b : Caml_obj_extern.t) : int =
           if len_a = len_b then
             if O.isArray(a)
             then aux_same_length a b 0 len_a
+            else if [%raw{|a instanceof Date && b instanceof Date|}] then 
+            [%raw{|a - b|}]
             else aux_obj_compare a b
           else if len_a < len_b then
             aux_length_a_short a b 0 len_a
@@ -327,6 +329,8 @@ let rec caml_equal (a : Caml_obj_extern.t) (b : Caml_obj_extern.t) : bool =
           if len_a = len_b then
             if O.isArray(a)
             then aux_equal_length a b 0 len_a
+            else if [%raw{|a instanceof Date && b instanceof Date|}] then
+            not (Js.unsafe_gt a  b || Js.unsafe_lt a  b)
             else aux_obj_equal a b
           else false
 and aux_equal_length  (a : Caml_obj_extern.t) (b : Caml_obj_extern.t) i same_length =

jscomp/test/js_date_test.js

@@ -2,6 +2,7 @@
 
 var Mt = require("./mt.js");
 var Block = require("../../lib/js/block.js");
+var Caml_obj = require("../../lib/js/caml_obj.js");
 
 function date(param) {
   return new Date("1976-03-08T12:34:56.789+01:23");
@@ -941,7 +942,18 @@ var suites_001 = /* :: */[
                                                                                                                                                 ]);
                                                                                                                                       })
                                                                                                                                   ],
-                                                                                                                                  /* [] */0
+                                                                                                                                  /* :: */[
+                                                                                                                                    /* tuple */[
+                                                                                                                                      "eq",
+                                                                                                                                      (function (param) {
+                                                                                                                                          var a = new Date("2013-03-01T01:10:00");
+                                                                                                                                          var b = new Date("2013-03-01T01:10:00");
+                                                                                                                                          var c = new Date("2013-03-01T01:10:01");
+                                                                                                                                          return /* Ok */Block.__(4, [Caml_obj.caml_equal(a, b) && Caml_obj.caml_notequal(b, c) && Caml_obj.caml_greaterthan(c, b)]);
+                                                                                                                                        })
+                                                                                                                                    ],
+                                                                                                                                    /* [] */0
+                                                                                                                                  ]
                                                                                                                                 ]
                                                                                                                               ]
                                                                                                                             ]
@@ -1015,6 +1027,9 @@ var suites = /* :: */[
 
 Mt.from_pair_suites("Js_date_test", suites);
 
+var N = 0;
+
+exports.N = N;
 exports.date = date;
 exports.suites = suites;
 /*  Not a pure module */