diff --git a/CHANGELOG.md b/CHANGELOG.md
index a445046183..c3483a1128 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@
 #### :nail_care: Polish
 
 - Make the `--help` arg be prioritized in the CLI, so correctly prints help message and skip other commands. https://github.com/rescript-lang/rescript-compiler/pull/6667
+- Remove redundant space for empty return in generated js code. https://github.com/rescript-lang/rescript-compiler/pull/6745
 - Remove redundant space for export in generated js code. https://github.com/rescript-lang/rescript-compiler/pull/6560
 
 # 11.1.0
diff --git a/jscomp/core/js_dump.ml b/jscomp/core/js_dump.ml
index 454f46d9a9..14d2d8c678 100644
--- a/jscomp/core/js_dump.ml
+++ b/jscomp/core/js_dump.ml
@@ -1205,7 +1205,7 @@ and statement_desc top cxt f (s : J.statement_desc) : cxt =
           semi f;
           cxt
       | Undefined _ ->
-          return_sp f;
+          P.string f L.return;
           semi f;
           cxt
       | _ ->
diff --git a/jscomp/test/406_primitive_test.js b/jscomp/test/406_primitive_test.js
index 63c11c6e41..5892abfb8f 100644
--- a/jscomp/test/406_primitive_test.js
+++ b/jscomp/test/406_primitive_test.js
@@ -42,12 +42,12 @@ function f(param) {
       }
       
     }
-    return ;
+    return;
   }
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === A) {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/jscomp/test/UntaggedVariants.js b/jscomp/test/UntaggedVariants.js
index c0299611c4..7d9c7b79d4 100644
--- a/jscomp/test/UntaggedVariants.js
+++ b/jscomp/test/UntaggedVariants.js
@@ -391,12 +391,12 @@ var someJson = '[{"name": "Haan"}, {"name": "Mr"}, false]';
 function check$1(s) {
   if (!Array.isArray(s) && (s === null || typeof s !== "object") && typeof s !== "number" && typeof s !== "string") {
     console.log("Nope...");
-    return ;
+    return;
   }
   if (Array.isArray(s)) {
     if (s.length !== 3) {
       console.log("Nope...");
-      return ;
+      return;
     }
     var match = s[0];
     if (match === true) {
@@ -405,23 +405,23 @@ function check$1(s) {
         var match$2 = s[2];
         if (!Array.isArray(match$2) && (match$2 === null || typeof match$2 !== "object") && typeof match$2 !== "number" && typeof match$2 !== "string") {
           console.log("Nope...");
-          return ;
+          return;
         }
         if (Array.isArray(match$2)) {
           if (match$2.length !== 2) {
             console.log("Nope...");
-            return ;
+            return;
           }
           var match$3 = match$2[0];
           if (!Array.isArray(match$3) && (match$3 === null || typeof match$3 !== "object") && typeof match$3 !== "number" && typeof match$3 !== "string") {
             console.log("Nope...");
-            return ;
+            return;
           }
           if (typeof match$3 === "string" && match$3 === "My name is") {
             var match$4 = match$2[1];
             if (!Array.isArray(match$4) && (match$4 === null || typeof match$4 !== "object") && typeof match$4 !== "number" && typeof match$4 !== "string") {
               console.log("Nope...");
-              return ;
+              return;
             }
             if (typeof match$4 === "number") {
               if (match$4 !== 10) {
@@ -429,29 +429,29 @@ function check$1(s) {
               } else {
                 console.log("yup");
               }
-              return ;
+              return;
             }
             console.log("Nope...");
-            return ;
+            return;
           } else {
             console.log("Nope...");
-            return ;
+            return;
           }
         } else {
           console.log("Nope...");
-          return ;
+          return;
         }
       } else {
         console.log("Nope...");
-        return ;
+        return;
       }
     } else {
       console.log("Nope...");
-      return ;
+      return;
     }
   } else {
     console.log("Nope...");
-    return ;
+    return;
   }
 }
 
@@ -494,28 +494,28 @@ async function classify$10(a) {
   if (typeof a !== "object" && !(a instanceof Promise) && (a === "test" || a === 12) && !Array.isArray(a)) {
     if (a === "test") {
       console.log("testing");
-      return ;
+      return;
     }
     console.log(12);
-    return ;
+    return;
   } else {
     if (Array.isArray(a)) {
       console.log(function (param) {
             return Belt_Array.joinWith(a, "-", param);
           });
-      return ;
+      return;
     }
     if (a instanceof Promise) {
       console.log(await a);
-      return ;
+      return;
     }
     switch (typeof a) {
       case "string" :
           console.log(a);
-          return ;
+          return;
       case "object" :
           console.log(a.userName);
-          return ;
+          return;
       
     }
   }
@@ -530,35 +530,35 @@ async function classifyAll(t) {
     console.log(function (param) {
           return Belt_Array.joinWith(t, "-", param);
         });
-    return ;
+    return;
   }
   if (t instanceof Promise) {
     console.log(await t);
-    return ;
+    return;
   }
   if (t instanceof Date) {
     console.log(t.toString());
-    return ;
+    return;
   }
   if (t instanceof RegExp) {
     console.log(t.test("test"));
-    return ;
+    return;
   }
   if (t instanceof File) {
     console.log(t.name);
-    return ;
+    return;
   }
   if (t instanceof Blob) {
     console.log(t.size);
-    return ;
+    return;
   }
   switch (typeof t) {
     case "string" :
         console.log(t);
-        return ;
+        return;
     case "object" :
         console.log(t.userName);
-        return ;
+        return;
     
   }
 }
diff --git a/jscomp/test/array_subtle_test.js b/jscomp/test/array_subtle_test.js
index be8be1555f..12a164c4a6 100644
--- a/jscomp/test/array_subtle_test.js
+++ b/jscomp/test/array_subtle_test.js
@@ -96,7 +96,7 @@ function fff(x) {
 function fff2(x) {
   if (x.length >= 10) {
     console.log("hi");
-    return ;
+    return;
   }
   
 }
diff --git a/jscomp/test/bdd.js b/jscomp/test/bdd.js
index a2314104bf..11f264f463 100644
--- a/jscomp/test/bdd.js
+++ b/jscomp/test/bdd.js
@@ -62,7 +62,7 @@ function resize(newSize) {
     while(true) {
       var bucket = _bucket;
       if (!bucket) {
-        return ;
+        return;
       }
       var n = bucket.hd;
       if (typeof n !== "object") {
@@ -111,7 +111,7 @@ function insert(idl, idh, v, ind, bucket, newNode) {
           tl: bucket
         });
     n_items.contents = n_items.contents + 1 | 0;
-    return ;
+    return;
   }
   resize((sz_1.contents + sz_1.contents | 0) + 2 | 0);
   var ind$1 = hashVal(idl, idh, v) & sz_1.contents;
@@ -398,7 +398,7 @@ function main(param) {
     succeeded = succeeded && test_hwb(bdd, random_vars(22));
   }
   if (succeeded) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
diff --git a/jscomp/test/bs_auto_uncurry.js b/jscomp/test/bs_auto_uncurry.js
index 31f7a653f2..23121c9c29 100644
--- a/jscomp/test/bs_auto_uncurry.js
+++ b/jscomp/test/bs_auto_uncurry.js
@@ -46,7 +46,7 @@ function f_01(param) {
   return hi(function (x) {
               if (x === undefined) {
                 console.log("x");
-                return ;
+                return;
               }
               
             });
diff --git a/jscomp/test/bs_hashtbl_string_test.js b/jscomp/test/bs_hashtbl_string_test.js
index f747ef5b4e..f7db275082 100644
--- a/jscomp/test/bs_hashtbl_string_test.js
+++ b/jscomp/test/bs_hashtbl_string_test.js
@@ -89,7 +89,7 @@ function bench2(m) {
     Belt_HashMap.remove(empty, String(i$2));
   }
   if (empty.size === 0) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -127,7 +127,7 @@ function bench3(m) {
     table = Belt_MapDict.remove(table, String(i$2), cmp);
   }
   if (Belt_MapDict.size(table) === 0) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -165,7 +165,7 @@ function bench4(param) {
     Belt_HashMapString.remove(table, String(i$2));
   }
   if (Belt_HashMapString.isEmpty(table)) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -207,7 +207,7 @@ function bench5(param) {
   }
   console.timeEnd("bs_hashtbl_string_test.res 122");
   if (Belt_HashMap.isEmpty(table)) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -243,7 +243,7 @@ function bench6(param) {
     Belt_HashMapInt.remove(table, i$2);
   }
   if (table.size === 0) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -279,7 +279,7 @@ function bench7(param) {
     Belt_HashSetInt.remove(table, i$2);
   }
   if (table.size === 0) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
diff --git a/jscomp/test/bs_rbset_int_bench.js b/jscomp/test/bs_rbset_int_bench.js
index c26328a964..b4f14d70ad 100644
--- a/jscomp/test/bs_rbset_int_bench.js
+++ b/jscomp/test/bs_rbset_int_bench.js
@@ -32,7 +32,7 @@ function bench(param) {
   }
   console.timeEnd("bs_rbset_int_bench.res 16");
   if (Rbset.cardinal(data) === 0) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
diff --git a/jscomp/test/bs_set_bench.js b/jscomp/test/bs_set_bench.js
index c522372a1a..0454ff5de2 100644
--- a/jscomp/test/bs_set_bench.js
+++ b/jscomp/test/bs_set_bench.js
@@ -32,7 +32,7 @@ function bench(param) {
   }
   console.timeEnd("bs_set_bench.res 16");
   if (Belt_SetInt.size(data) === 0) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
diff --git a/jscomp/test/custom_error_test.js b/jscomp/test/custom_error_test.js
index 5d2c407636..333414d2a0 100644
--- a/jscomp/test/custom_error_test.js
+++ b/jscomp/test/custom_error_test.js
@@ -13,7 +13,7 @@ function test_js_error(param) {
     var err = Caml_js_exceptions.internalToOCamlException(raw_err);
     if (err.RE_EXN_ID === Js_exn.$$Error) {
       console.log(err._1.stack);
-      return ;
+      return;
     }
     throw err;
   }
@@ -43,7 +43,7 @@ function example1(param) {
     var err = Caml_js_exceptions.internalToOCamlException(raw_err);
     if (err.RE_EXN_ID === Js_exn.$$Error) {
       console.log(err._1.stack);
-      return ;
+      return;
     }
     throw err;
   }
@@ -57,7 +57,7 @@ function example2(param) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === Js_exn.$$Error) {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/jscomp/test/equal_exception_test.js b/jscomp/test/equal_exception_test.js
index 454bba7561..5c6e0b5507 100644
--- a/jscomp/test/equal_exception_test.js
+++ b/jscomp/test/equal_exception_test.js
@@ -48,7 +48,7 @@ function is_equal(param) {
         };
   }
   if (Caml_string.get(v, 0) === /* 'g' */103) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -71,7 +71,7 @@ function is_exception(param) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Not_found") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -90,7 +90,7 @@ function is_normal_exception(_x) {
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === A) {
       if (exn._1 === 3) {
-        return ;
+        return;
       }
       throw exn;
     }
@@ -107,7 +107,7 @@ function is_arbitrary_exception(param) {
         };
   }
   catch (exn){
-    return ;
+    return;
   }
 }
 
diff --git a/jscomp/test/ext_array_test.js b/jscomp/test/ext_array_test.js
index 63c7b97580..b0d750cc45 100644
--- a/jscomp/test/ext_array_test.js
+++ b/jscomp/test/ext_array_test.js
@@ -9,7 +9,7 @@ var Caml_option = require("../../lib/js/caml_option.js");
 
 function reverse_range(a, i, len) {
   if (len === 0) {
-    return ;
+    return;
   }
   for(var k = 0 ,k_finish = (len - 1 | 0) / 2 | 0; k <= k_finish; ++k){
     var t = a[i + k | 0];
diff --git a/jscomp/test/ext_list_test.js b/jscomp/test/ext_list_test.js
index bb16453a47..b7635b4845 100644
--- a/jscomp/test/ext_list_test.js
+++ b/jscomp/test/ext_list_test.js
@@ -606,7 +606,7 @@ function find_first_not(p, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     var a = x.hd;
     if (!Curry._1(p, a)) {
@@ -621,7 +621,7 @@ function for_all_opt(p, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     var v = Curry._1(p, x.hd);
     if (v !== undefined) {
@@ -702,7 +702,7 @@ function find_no_exn(p, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     var x$1 = x.hd;
     if (Curry._1(p, x$1)) {
@@ -717,7 +717,7 @@ function find_opt(p, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     var v = Curry._1(p, x.hd);
     if (v !== undefined) {
diff --git a/jscomp/test/ext_string_test.js b/jscomp/test/ext_string_test.js
index 16a5f6d07a..8f2272a2b8 100644
--- a/jscomp/test/ext_string_test.js
+++ b/jscomp/test/ext_string_test.js
@@ -158,7 +158,7 @@ function check_any_suffix_case_then_chop(s, suffixes) {
   while(true) {
     var suffixes$1 = _suffixes;
     if (!suffixes$1) {
-      return ;
+      return;
     }
     var id = ends_with_index(s, suffixes$1.hd);
     if (id >= 0) {
@@ -411,7 +411,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
diff --git a/jscomp/test/format_regression.js b/jscomp/test/format_regression.js
index d591f1cd78..df30f34ff6 100644
--- a/jscomp/test/format_regression.js
+++ b/jscomp/test/format_regression.js
@@ -57,7 +57,7 @@ function advance_loop(state) {
     var size = match.elem_size;
     var size$1 = int_of_size(size);
     if (size$1 < 0 && (state.pp_right_total - state.pp_left_total | 0) < state.pp_space_left) {
-      return ;
+      return;
     }
     take_queue(state.pp_queue);
     Curry._1(format_pp_token(state, size$1 < 0 ? 1000000010 : size$1), match.token);
diff --git a/jscomp/test/gpr_1701_test.js b/jscomp/test/gpr_1701_test.js
index 6e3e2048ce..be682196d6 100644
--- a/jscomp/test/gpr_1701_test.js
+++ b/jscomp/test/gpr_1701_test.js
@@ -20,7 +20,7 @@ function test(n) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === Foo) {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/jscomp/test/gpr_3875_test.js b/jscomp/test/gpr_3875_test.js
index 291db720ec..17bd77d4ec 100644
--- a/jscomp/test/gpr_3875_test.js
+++ b/jscomp/test/gpr_3875_test.js
@@ -28,7 +28,7 @@ function compilerBug(a, b, c, f) {
       } else {
         result.contents = "No x, c is false";
       }
-      return ;
+      return;
     }
     if (b !== "x") {
       if (c) {
@@ -36,7 +36,7 @@ function compilerBug(a, b, c, f) {
       } else {
         result.contents = "No x, c is false";
       }
-      return ;
+      return;
     }
     
   }
diff --git a/jscomp/test/gpr_4069_test.js b/jscomp/test/gpr_4069_test.js
index d9fdf4e7b9..b2a58b83e4 100644
--- a/jscomp/test/gpr_4069_test.js
+++ b/jscomp/test/gpr_4069_test.js
@@ -5,7 +5,7 @@ var Curry = require("../../lib/js/curry.js");
 
 function f(value) {
   if (value == null) {
-    return ;
+    return;
   } else {
     return value;
   }
diff --git a/jscomp/test/gpr_4519_test.js b/jscomp/test/gpr_4519_test.js
index bebe7f0f41..30bc3be279 100644
--- a/jscomp/test/gpr_4519_test.js
+++ b/jscomp/test/gpr_4519_test.js
@@ -20,7 +20,7 @@ function nextFor(x) {
     if (x === "Required") {
       return "Optional";
     } else {
-      return ;
+      return;
     }
   } else {
     return "Required";
diff --git a/jscomp/test/gpr_858_unit2_test.js b/jscomp/test/gpr_858_unit2_test.js
index 3f5bf7873e..98000fc476 100644
--- a/jscomp/test/gpr_858_unit2_test.js
+++ b/jscomp/test/gpr_858_unit2_test.js
@@ -18,10 +18,10 @@ for(var i = 1; i <= 2; ++i){
           Curry._1(prev, undefined);
           f(((n + 1 | 0) + i | 0) - i | 0, x - 1 | 0);
         });
-      return ;
+      return;
     }
     if (i === n) {
-      return ;
+      return;
     }
     throw {
           RE_EXN_ID: "Assert_failure",
diff --git a/jscomp/test/imm_map_bench.js b/jscomp/test/imm_map_bench.js
index 63b569c7c7..3921535bd4 100644
--- a/jscomp/test/imm_map_bench.js
+++ b/jscomp/test/imm_map_bench.js
@@ -18,7 +18,7 @@ function fromArray(kvs) {
 
 function should(b) {
   if (b) {
-    return ;
+    return;
   }
   throw new Error("impossible");
 }
diff --git a/jscomp/test/inline_map2_test.js b/jscomp/test/inline_map2_test.js
index 9613eb9862..c30c963158 100644
--- a/jscomp/test/inline_map2_test.js
+++ b/jscomp/test/inline_map2_test.js
@@ -251,7 +251,7 @@ function Make(Ord) {
     while(true) {
       var x = _x;
       if (typeof x !== "object") {
-        return ;
+        return;
       }
       iter(f, x._0);
       Curry._2(f, x._1, x._2);
@@ -887,7 +887,7 @@ function iter(f, _x) {
   while(true) {
     var x = _x;
     if (typeof x !== "object") {
-      return ;
+      return;
     }
     iter(f, x._0);
     Curry._2(f, x._1, x._2);
@@ -1571,7 +1571,7 @@ function iter$1(f, _x) {
   while(true) {
     var x = _x;
     if (typeof x !== "object") {
-      return ;
+      return;
     }
     iter$1(f, x._0);
     Curry._2(f, x._1, x._2);
diff --git a/jscomp/test/inline_record_test.js b/jscomp/test/inline_record_test.js
index 25d6b5c3fe..731c0081cf 100644
--- a/jscomp/test/inline_record_test.js
+++ b/jscomp/test/inline_record_test.js
@@ -154,7 +154,7 @@ function ff0(x) {
   if (x.RE_EXN_ID === A4) {
     x.x = x.x + 1 | 0;
     x.z = x.z + 1 | 0;
-    return ;
+    return;
   }
   
 }
diff --git a/jscomp/test/int64_test.js b/jscomp/test/int64_test.js
index 38dae459a6..790a938ef1 100644
--- a/jscomp/test/int64_test.js
+++ b/jscomp/test/int64_test.js
@@ -2149,7 +2149,7 @@ function id(loc, x) {
   var float_value = Caml_int64.float_of_bits(x);
   var match = Pervasives.classify_float(float_value);
   if (match === "FP_nan") {
-    return ;
+    return;
   } else {
     return eq(loc, Caml_int64.bits_of_float(float_value), x);
   }
diff --git a/jscomp/test/int_map.js b/jscomp/test/int_map.js
index 1b72bbb29c..f774596cef 100644
--- a/jscomp/test/int_map.js
+++ b/jscomp/test/int_map.js
@@ -216,7 +216,7 @@ function find_first_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -293,7 +293,7 @@ function find_last_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -330,7 +330,7 @@ function find_opt(x, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var c = Caml.int_compare(x, param.v);
     if (c === 0) {
@@ -381,7 +381,7 @@ function min_binding_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var l = param.l;
     if (typeof l !== "object") {
@@ -420,7 +420,7 @@ function max_binding_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var r = param.r;
     if (typeof r !== "object") {
@@ -549,7 +549,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     iter(f, param.l);
     Curry._2(f, param.v, param.d);
diff --git a/jscomp/test/js_json_test.js b/jscomp/test/js_json_test.js
index 8068a48e4c..29fdc0e966 100644
--- a/jscomp/test/js_json_test.js
+++ b/jscomp/test/js_json_test.js
@@ -108,7 +108,7 @@ add_test("File \"js_json_test.res\", line 22, characters 11-18", (function (para
                     };
               }
               if (ty3.TAG === "JSONNumber") {
-                return ;
+                return;
               }
               throw {
                     RE_EXN_ID: "Assert_failure",
@@ -757,7 +757,7 @@ idtest({
 
 idtest(Belt_List.makeBy(500, (function (i) {
             if (i % 2 === 0) {
-              return ;
+              return;
             } else {
               return 1;
             }
@@ -765,7 +765,7 @@ idtest(Belt_List.makeBy(500, (function (i) {
 
 idtest(Belt_Array.makeBy(500, (function (i) {
             if (i % 2 === 0) {
-              return ;
+              return;
             } else {
               return 1;
             }
diff --git a/jscomp/test/large_record_duplication_test.js b/jscomp/test/large_record_duplication_test.js
index f1942416e2..a95eb3cb73 100644
--- a/jscomp/test/large_record_duplication_test.js
+++ b/jscomp/test/large_record_duplication_test.js
@@ -86,7 +86,7 @@ var v1 = {
 
 function get_x0(x) {
   if (typeof x !== "object") {
-    return ;
+    return;
   } else {
     return x.x0;
   }
diff --git a/jscomp/test/mario_game.js b/jscomp/test/mario_game.js
index 6983adb8ad..f73eb9fa40 100644
--- a/jscomp/test/mario_game.js
+++ b/jscomp/test/mario_game.js
@@ -673,13 +673,13 @@ function update_animation(spr) {
     spr.ticks.contents = 0;
     if (spr.params.loop) {
       spr.frame.contents = Caml_int32.mod_(spr.frame.contents + 1 | 0, spr.params.max_frames);
-      return ;
+      return;
     } else {
-      return ;
+      return;
     }
   } else {
     spr.ticks.contents = curr_ticks + 1 | 0;
-    return ;
+    return;
   }
 }
 
@@ -965,9 +965,9 @@ function update_player(player, keys, context) {
                     player.vel.x = player.vel.x - (0.4 - lr_acc);
                   }
                   player.dir = "Left";
-                  return ;
+                  return;
                 } else {
-                  return ;
+                  return;
                 }
             case "CRight" :
                 if (!player.crouch) {
@@ -975,25 +975,25 @@ function update_player(player, keys, context) {
                     player.vel.x = player.vel.x + (0.4 + lr_acc);
                   }
                   player.dir = "Right";
-                  return ;
+                  return;
                 } else {
-                  return ;
+                  return;
                 }
             case "CUp" :
                 if (!player.jumping && player.grounded) {
                   player.jumping = true;
                   player.grounded = false;
                   player.vel.y = Caml.float_max(player.vel.y - (5.7 + Math.abs(player.vel.x) * 0.25), -6);
-                  return ;
+                  return;
                 } else {
-                  return ;
+                  return;
                 }
             case "CDown" :
                 if (!player.jumping && player.grounded) {
                   player.crouch = true;
-                  return ;
+                  return;
                 } else {
-                  return ;
+                  return;
                 }
             
           }
@@ -1048,19 +1048,19 @@ function update_player(player, keys, context) {
                 }, player.dir, context)
           ];
   } else {
-    return ;
+    return;
   }
 }
 
 function update_vel$1(obj) {
   if (obj.grounded) {
     obj.vel.y = 0;
-    return ;
+    return;
   } else if (obj.params.has_gravity) {
     obj.vel.y = Caml.float_min(obj.vel.y + 0.2 + Math.abs(obj.vel.y) * 0.01, 4.5);
-    return ;
+    return;
   } else {
-    return ;
+    return;
   }
 }
 
@@ -1068,7 +1068,7 @@ function update_pos(obj) {
   obj.pos.x = obj.vel.x + obj.pos.x;
   if (obj.params.has_gravity) {
     obj.pos.y = obj.vel.y + obj.pos.y;
-    return ;
+    return;
   }
   
 }
@@ -1078,7 +1078,7 @@ function process_obj(obj, mapy) {
   update_pos(obj);
   if (obj.pos.y > mapy) {
     obj.kill = true;
-    return ;
+    return;
   }
   
 }
@@ -1096,12 +1096,12 @@ function collide_block(check_xOpt, dir, obj) {
   switch (dir) {
     case "North" :
         obj.vel.y = -0.001;
-        return ;
+        return;
     case "South" :
         obj.vel.y = 0;
         obj.grounded = true;
         obj.jumping = false;
-        return ;
+        return;
     case "East" :
     case "West" :
         break;
@@ -1109,7 +1109,7 @@ function collide_block(check_xOpt, dir, obj) {
   }
   if (check_x) {
     obj.vel.x = 0;
-    return ;
+    return;
   }
   
 }
@@ -1131,7 +1131,7 @@ function evolve_enemy(player_dir, typ, spr, obj, context) {
   switch (typ) {
     case "Goomba" :
         obj.kill = true;
-        return ;
+        return;
     case "GKoopa" :
         var match = make$2(undefined, obj.dir, {
               TAG: "SEnemy",
@@ -1190,12 +1190,12 @@ function dec_health(obj) {
   var health = obj.health - 1 | 0;
   if (health === 0) {
     obj.kill = true;
-    return ;
+    return;
   } else if (obj.invuln === 0) {
     obj.health = health;
-    return ;
+    return;
   } else {
-    return ;
+    return;
   }
 }
 
@@ -1293,14 +1293,14 @@ function check_collision(c1, c2) {
   var b2 = get_aabb(c2);
   var o1 = c1._2;
   if (col_bypass(c1, c2)) {
-    return ;
+    return;
   }
   var vx = b1.center.x - b2.center.x;
   var vy = b1.center.y - b2.center.y;
   var hwidths = b1.half.x + b2.half.x;
   var hheights = b1.half.y + b2.half.y;
   if (!(Math.abs(vx) < hwidths && Math.abs(vy) < hheights)) {
-    return ;
+    return;
   }
   var ox = hwidths - Math.abs(vx);
   var oy = hheights - Math.abs(vy);
@@ -2348,7 +2348,7 @@ function update_loop(canvas, param, map_dim) {
                 hd: part,
                 tl: particles.contents
               };
-              return ;
+              return;
             }
             
           }), parts);
diff --git a/jscomp/test/mock_mt.js b/jscomp/test/mock_mt.js
index 29acadccfe..9deec3bf35 100644
--- a/jscomp/test/mock_mt.js
+++ b/jscomp/test/mock_mt.js
@@ -20,7 +20,7 @@ function from_pair_suites(name, suites) {
                       "eq?",
                       fn._1
                     ]);
-                return ;
+                return;
             case "Neq" :
                 console.log([
                       name,
@@ -28,7 +28,7 @@ function from_pair_suites(name, suites) {
                       "neq?",
                       fn._1
                     ]);
-                return ;
+                return;
             case "StrictEq" :
                 console.log([
                       name,
@@ -36,7 +36,7 @@ function from_pair_suites(name, suites) {
                       "strict_eq?",
                       fn._1
                     ]);
-                return ;
+                return;
             case "StrictNeq" :
                 console.log([
                       name,
@@ -44,14 +44,14 @@ function from_pair_suites(name, suites) {
                       "strict_neq?",
                       fn._1
                     ]);
-                return ;
+                return;
             case "Ok" :
                 console.log([
                       name,
                       fn._0,
                       "ok?"
                     ]);
-                return ;
+                return;
             case "Approx" :
                 console.log([
                       name,
@@ -59,7 +59,7 @@ function from_pair_suites(name, suites) {
                       "~",
                       fn._1
                     ]);
-                return ;
+                return;
             case "ApproxThreshold" :
                 console.log([
                       name,
@@ -70,15 +70,15 @@ function from_pair_suites(name, suites) {
                       fn._0,
                       ")"
                     ]);
-                return ;
+                return;
             case "ThrowAny" :
-                return ;
+                return;
             case "Fail" :
                 console.log("failed");
-                return ;
+                return;
             case "FailWith" :
                 console.log("failed: " + fn._0);
-                return ;
+                return;
             
           }
         }), suites);
diff --git a/jscomp/test/mt.js b/jscomp/test/mt.js
index ba3c501e1a..e9335cc3cd 100644
--- a/jscomp/test/mt.js
+++ b/jscomp/test/mt.js
@@ -54,40 +54,40 @@ function handleCode(spec) {
   switch (spec.TAG) {
     case "Eq" :
         Assert.deepEqual(spec._0, spec._1);
-        return ;
+        return;
     case "Neq" :
         Assert.notDeepEqual(spec._0, spec._1);
-        return ;
+        return;
     case "StrictEq" :
         Assert.strictEqual(spec._0, spec._1);
-        return ;
+        return;
     case "StrictNeq" :
         Assert.notStrictEqual(spec._0, spec._1);
-        return ;
+        return;
     case "Ok" :
         Assert.ok(spec._0);
-        return ;
+        return;
     case "Approx" :
         var b = spec._1;
         var a = spec._0;
         if (!close_enough(undefined, a, b)) {
           Assert.deepEqual(a, b);
-          return ;
+          return;
         } else {
-          return ;
+          return;
         }
     case "ApproxThreshold" :
         var b$1 = spec._2;
         var a$1 = spec._1;
         if (!close_enough(spec._0, a$1, b$1)) {
           Assert.deepEqual(a$1, b$1);
-          return ;
+          return;
         } else {
-          return ;
+          return;
         }
     case "ThrowAny" :
         Assert.throws(spec._0);
-        return ;
+        return;
     case "Fail" :
         return assert_fail("failed");
     case "FailWith" :
@@ -246,7 +246,7 @@ function old_from_promise_suites_donotuse(name, suites) {
     } else {
       console.log("promise suites");
     }
-    return ;
+    return;
   }
   
 }
diff --git a/jscomp/test/ocaml_re_test.js b/jscomp/test/ocaml_re_test.js
index 041f35e63e..33adfd510c 100644
--- a/jscomp/test/ocaml_re_test.js
+++ b/jscomp/test/ocaml_re_test.js
@@ -271,10 +271,10 @@ function hash_rec(x) {
 
 function one_char(x) {
   if (!x) {
-    return ;
+    return;
   }
   if (x.tl) {
-    return ;
+    return;
   }
   var match = x.hd;
   var i = match[0];
@@ -658,7 +658,7 @@ function first(f, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     var res = Curry._1(f, x.hd);
     if (res !== undefined) {
@@ -1248,7 +1248,7 @@ function delta_1(marks, c, next_cat, prev_cat, x, rem) {
                 switch (x.TAG) {
                   case "TSeq" :
                   case "TExp" :
-                      return ;
+                      return;
                   case "TMatch" :
                       return x._0;
                   
@@ -1363,7 +1363,7 @@ function delta_seq(c, next_cat, prev_cat, kind, y, z, rem) {
           switch (x.TAG) {
             case "TSeq" :
             case "TExp" :
-                return ;
+                return;
             case "TMatch" :
                 return x._0;
             
@@ -1803,7 +1803,7 @@ function split(s, cm) {
   while(true) {
     var t = _t;
     if (!t) {
-      return ;
+      return;
     }
     var match = t.hd;
     Curry._2(f, match[0], match[1]);
@@ -1869,12 +1869,12 @@ function colorize(c, regexp) {
               return split(cword, c);
           case "Last_end_of_line" :
               lnl.contents = true;
-              return ;
+              return;
           case "Beg_of_str" :
           case "End_of_str" :
           case "Start" :
           case "Stop" :
-              return ;
+              return;
           
         }
       } else {
@@ -3674,12 +3674,12 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
   };
   var integer = function (param) {
     if (i.contents === l) {
-      return ;
+      return;
     }
     var d = get();
     if (d > 57 || d < 48) {
       i.contents = i.contents - 1 | 0;
-      return ;
+      return;
     } else {
       var _i = d - /* '0' */48 | 0;
       while(true) {
diff --git a/jscomp/test/offset.js b/jscomp/test/offset.js
index 361b23e053..06e157d58a 100644
--- a/jscomp/test/offset.js
+++ b/jscomp/test/offset.js
@@ -188,7 +188,7 @@ function min_elt_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var l = param.l;
     if (typeof l !== "object") {
@@ -221,7 +221,7 @@ function max_elt_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var r = param.r;
     if (typeof r !== "object") {
@@ -515,7 +515,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     iter(f, param.l);
     Curry._1(f, param.v);
@@ -705,7 +705,7 @@ function find_first_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -770,7 +770,7 @@ function find_last_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -801,7 +801,7 @@ function find_opt(x, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     var c = Caml.string_compare(x, v);
diff --git a/jscomp/test/queue_402.js b/jscomp/test/queue_402.js
index cbcd9205fa..ab660ef5b8 100644
--- a/jscomp/test/queue_402.js
+++ b/jscomp/test/queue_402.js
@@ -26,7 +26,7 @@ function add(x, q) {
     cell.next = cell;
     q.length = 1;
     q.tail = cell;
-    return ;
+    return;
   }
   var tail = q.tail;
   var head = tail.next;
@@ -85,7 +85,7 @@ function copy(q) {
       var cell = _cell;
       var prev = _prev;
       if (cell === tail) {
-        return ;
+        return;
       }
       var res = {
         content: cell.content,
@@ -114,7 +114,7 @@ function length(q) {
 
 function iter(f, q) {
   if (q.length <= 0) {
-    return ;
+    return;
   }
   var tail = q.tail;
   var _cell = tail.next;
@@ -122,7 +122,7 @@ function iter(f, q) {
     var cell = _cell;
     Curry._1(f, cell.content);
     if (cell === tail) {
-      return ;
+      return;
     }
     _cell = cell.next;
     continue ;
@@ -152,7 +152,7 @@ function fold(f, accu, q) {
 function transfer(q1, q2) {
   var length1 = q1.length;
   if (length1 <= 0) {
-    return ;
+    return;
   }
   var tail1 = q1.tail;
   clear(q1);
diff --git a/jscomp/test/reasonReactRouter.js b/jscomp/test/reasonReactRouter.js
index 708d608960..b5d611445b 100644
--- a/jscomp/test/reasonReactRouter.js
+++ b/jscomp/test/reasonReactRouter.js
@@ -82,7 +82,7 @@ function push(path) {
   if (match !== undefined && match$1 !== undefined) {
     match.pushState(null, "", path);
     match$1.dispatchEvent(safeMakeEvent("popstate"));
-    return ;
+    return;
   }
   
 }
@@ -93,7 +93,7 @@ function replace(path) {
   if (match !== undefined && match$1 !== undefined) {
     match.replaceState(null, "", path);
     match$1.dispatchEvent(safeMakeEvent("popstate"));
-    return ;
+    return;
   }
   
 }
@@ -153,7 +153,7 @@ function unwatchUrl(watcherID) {
   var $$window = typeof window === "undefined" ? undefined : window;
   if ($$window !== undefined) {
     $$window.removeEventListener("popstate", watcherID);
-    return ;
+    return;
   }
   
 }
diff --git a/jscomp/test/rec_module_test.js b/jscomp/test/rec_module_test.js
index 88e1ea91db..4fde76bdcc 100644
--- a/jscomp/test/rec_module_test.js
+++ b/jscomp/test/rec_module_test.js
@@ -276,7 +276,7 @@ function min_elt_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var l = param.l;
     if (typeof l !== "object") {
@@ -309,7 +309,7 @@ function max_elt_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var r = param.r;
     if (typeof r !== "object") {
@@ -603,7 +603,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     iter(f, param.l);
     Curry._1(f, param.v);
@@ -793,7 +793,7 @@ function find_first_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -858,7 +858,7 @@ function find_last_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -889,7 +889,7 @@ function find_opt(x, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     var c = Curry._2(AAA.compare, x, v);
diff --git a/jscomp/test/set_gen.js b/jscomp/test/set_gen.js
index 470740414b..ef79fa19f2 100644
--- a/jscomp/test/set_gen.js
+++ b/jscomp/test/set_gen.js
@@ -117,7 +117,7 @@ function iter(f, _x) {
   while(true) {
     var x = _x;
     if (typeof x !== "object") {
-      return ;
+      return;
     }
     iter(f, x._0);
     Curry._1(f, x._1);
diff --git a/jscomp/test/sexp.js b/jscomp/test/sexp.js
index 29bf3a1c53..b6842fafc7 100644
--- a/jscomp/test/sexp.js
+++ b/jscomp/test/sexp.js
@@ -172,7 +172,7 @@ function map_opt(f, l) {
     }
     var y = Curry._1(f, l$1.hd);
     if (y === undefined) {
-      return ;
+      return;
     }
     _l = l$1.tl;
     _acc = {
@@ -189,7 +189,7 @@ function list_any(f, e) {
     while(true) {
       var l = _l;
       if (!l) {
-        return ;
+        return;
       }
       var res = Curry._1(f, l.hd);
       if (res !== undefined) {
@@ -232,13 +232,13 @@ function list_all(f, e) {
 
 function _try_atom(e, f) {
   if (e.NAME === "List") {
-    return ;
+    return;
   }
   try {
     return Caml_option.some(Curry._1(f, e.VAL));
   }
   catch (exn){
-    return ;
+    return;
   }
 }
 
@@ -262,14 +262,14 @@ function to_string(e) {
 
 function to_pair(e) {
   if (typeof e !== "object") {
-    return ;
+    return;
   }
   if (e.NAME !== "List") {
-    return ;
+    return;
   }
   var match = e.VAL;
   if (!match) {
-    return ;
+    return;
   }
   var match$1 = match.tl;
   if (match$1 && !match$1.tl) {
@@ -297,18 +297,18 @@ function to_pair_with(f1, f2, e) {
 
 function to_triple(e) {
   if (typeof e !== "object") {
-    return ;
+    return;
   }
   if (e.NAME !== "List") {
-    return ;
+    return;
   }
   var match = e.VAL;
   if (!match) {
-    return ;
+    return;
   }
   var match$1 = match.tl;
   if (!match$1) {
-    return ;
+    return;
   }
   var match$2 = match$1.tl;
   if (match$2 && !match$2.tl) {
@@ -359,7 +359,7 @@ function get_field(name, e) {
     while(true) {
       var l = _l;
       if (!l) {
-        return ;
+        return;
       }
       var match = l.hd;
       if (typeof match === "object") {
@@ -411,7 +411,7 @@ function _get_field_list(name, _l) {
   while(true) {
     var l = _l;
     if (!l) {
-      return ;
+      return;
     }
     var match = l.hd;
     if (typeof match === "object") {
@@ -455,7 +455,7 @@ function _get_variant(s, args, _l) {
   while(true) {
     var l = _l;
     if (!l) {
-      return ;
+      return;
     }
     var match = l.hd;
     if (Caml_obj.equal(s, match[0])) {
@@ -472,7 +472,7 @@ function get_variant(l, e) {
   }
   var match = e.VAL;
   if (!match) {
-    return ;
+    return;
   }
   var match$1 = match.hd;
   if (typeof match$1 === "object" && match$1.NAME === "Atom") {
diff --git a/jscomp/test/test_for_map.js b/jscomp/test/test_for_map.js
index 3e2f06acf9..b4f801e495 100644
--- a/jscomp/test/test_for_map.js
+++ b/jscomp/test/test_for_map.js
@@ -216,7 +216,7 @@ function find_first_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -293,7 +293,7 @@ function find_last_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -330,7 +330,7 @@ function find_opt(x, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var c = Caml.int_compare(x, param.v);
     if (c === 0) {
@@ -381,7 +381,7 @@ function min_binding_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var l = param.l;
     if (typeof l !== "object") {
@@ -420,7 +420,7 @@ function max_binding_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var r = param.r;
     if (typeof r !== "object") {
@@ -549,7 +549,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     iter(f, param.l);
     Curry._2(f, param.v, param.d);
diff --git a/jscomp/test/test_list.js b/jscomp/test/test_list.js
index 9ce963aaf7..6aa3f67718 100644
--- a/jscomp/test/test_list.js
+++ b/jscomp/test/test_list.js
@@ -150,7 +150,7 @@ function iter(f, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     Curry._1(f, x.hd);
     _x = x.tl;
@@ -165,7 +165,7 @@ function iteri(f, l) {
     var x = _x;
     var i = _i;
     if (!x) {
-      return ;
+      return;
     }
     Curry._2(f, i, x.hd);
     _x = x.tl;
@@ -273,7 +273,7 @@ function iter2(f, _l1, _l2) {
           };
     }
     if (!l2) {
-      return ;
+      return;
     }
     throw {
           RE_EXN_ID: "Invalid_argument",
diff --git a/jscomp/test/test_per.js b/jscomp/test/test_per.js
index 27edfb87f7..8e1ac999e1 100644
--- a/jscomp/test/test_per.js
+++ b/jscomp/test/test_per.js
@@ -221,7 +221,7 @@ function flush_all(param) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     try {
       Caml_external_polyfill.resolve("ml_flush")(x.hd);
@@ -284,7 +284,7 @@ function close_out_noerr(oc) {
     return Caml_external_polyfill.resolve("ml_close_channel")(oc);
   }
   catch (exn$1){
-    return ;
+    return;
   }
 }
 
@@ -328,7 +328,7 @@ function unsafe_really_input(ic, s, _ofs, _len) {
     var len = _len;
     var ofs = _ofs;
     if (len <= 0) {
-      return ;
+      return;
     }
     var r = Caml_external_polyfill.resolve("ml_input")(ic, s, ofs, len);
     if (r === 0) {
@@ -420,7 +420,7 @@ function close_in_noerr(ic) {
     return Caml_external_polyfill.resolve("ml_close_channel")(ic);
   }
   catch (exn){
-    return ;
+    return;
   }
 }
 
diff --git a/jscomp/test/test_set.js b/jscomp/test/test_set.js
index 3a494d2114..8c591e29c0 100644
--- a/jscomp/test/test_set.js
+++ b/jscomp/test/test_set.js
@@ -444,7 +444,7 @@ function Make(Ord) {
     while(true) {
       var x_ = _x_;
       if (typeof x_ !== "object") {
-        return ;
+        return;
       }
       iter(f, x_._0);
       Curry._1(f, x_._1);
diff --git a/jscomp/test/test_trywith.js b/jscomp/test/test_trywith.js
index efba275edf..1f55a1f523 100644
--- a/jscomp/test/test_trywith.js
+++ b/jscomp/test/test_trywith.js
@@ -110,7 +110,7 @@ function ff(g, x) {
   catch (raw_exn$9){
     var exn$9 = Caml_js_exceptions.internalToOCamlException(raw_exn$9);
     if (exn$9.RE_EXN_ID === "Undefined_recursive_module") {
-      return ;
+      return;
     }
     throw exn$9;
   }
diff --git a/jscomp/test/test_zero_nullable.js b/jscomp/test/test_zero_nullable.js
index 8feee60e84..346dcaae36 100644
--- a/jscomp/test/test_zero_nullable.js
+++ b/jscomp/test/test_zero_nullable.js
@@ -89,7 +89,7 @@ var u = f8(undefined);
 
 function f9(x) {
   if (x === null) {
-    return ;
+    return;
   } else {
     return Caml_option.some(x);
   }
@@ -174,7 +174,7 @@ var u$1 = f8$1(undefined);
 
 function f9$1(x) {
   if (x === undefined) {
-    return ;
+    return;
   } else {
     return Caml_option.some(x);
   }
@@ -257,7 +257,7 @@ var u$2 = f8$2(undefined);
 
 function f9$2(x) {
   if (x == null) {
-    return ;
+    return;
   } else {
     return Caml_option.some(x);
   }
diff --git a/jscomp/test/ticker.js b/jscomp/test/ticker.js
index 7ba853fbeb..48e1a490bb 100644
--- a/jscomp/test/ticker.js
+++ b/jscomp/test/ticker.js
@@ -89,7 +89,7 @@ function print_all_composite(all_tickers) {
   List.iter((function (x) {
           var tmp = x.type_;
           if (typeof tmp !== "object") {
-            return ;
+            return;
           }
           console.log(x.ticker_name);
         }), all_tickers);
@@ -306,7 +306,7 @@ function find_first_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -383,7 +383,7 @@ function find_last_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -420,7 +420,7 @@ function find_opt(x, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var c = Caml_obj.compare(x, param.v);
     if (c === 0) {
@@ -471,7 +471,7 @@ function min_binding_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var l = param.l;
     if (typeof l !== "object") {
@@ -510,7 +510,7 @@ function max_binding_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var r = param.r;
     if (typeof r !== "object") {
@@ -639,7 +639,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     iter(f, param.l);
     Curry._2(f, param.v, param.d);
@@ -1191,7 +1191,7 @@ function process_quote(ticker_map, new_ticker, new_value) {
           if (typeof match !== "object") {
             if (ticker.ticker_name === new_ticker) {
               ticker.value = new_value;
-              return ;
+              return;
             }
             throw {
                   RE_EXN_ID: "Failure",
diff --git a/jscomp/test/topsort_test.js b/jscomp/test/topsort_test.js
index 99cc0d59e1..79bc92dff0 100644
--- a/jscomp/test/topsort_test.js
+++ b/jscomp/test/topsort_test.js
@@ -406,7 +406,7 @@ function unsafe_topsort(graph) {
   };
   var sort_node = function (node) {
     if (List.mem(node, visited.contents)) {
-      return ;
+      return;
     }
     var nodes = nexts(node, graph);
     List.iter(sort_node, nodes);
@@ -632,7 +632,7 @@ function min_elt_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var l = param.l;
     if (typeof l !== "object") {
@@ -665,7 +665,7 @@ function max_elt_opt(_param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var r = param.r;
     if (typeof r !== "object") {
@@ -959,7 +959,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     iter(f, param.l);
     Curry._1(f, param.v);
@@ -1149,7 +1149,7 @@ function find_first_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -1214,7 +1214,7 @@ function find_last_opt(f, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     if (Curry._1(f, v)) {
@@ -1245,7 +1245,7 @@ function find_opt(x, _param) {
   while(true) {
     var param = _param;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var v = param.v;
     var c = Caml.string_compare(x, v);
@@ -1492,7 +1492,7 @@ function pathsort(graph) {
         hd: node,
         tl: visited.contents
       };
-      return ;
+      return;
     }
     
   };
diff --git a/jscomp/test/undef_regression2_test.js b/jscomp/test/undef_regression2_test.js
index 4339df8862..f9c83da664 100644
--- a/jscomp/test/undef_regression2_test.js
+++ b/jscomp/test/undef_regression2_test.js
@@ -70,7 +70,7 @@ function test2(param) {
 function test3(param) {
   if (Caml_option.undefined_to_opt(typeof __DEV__ === "undefined" ? undefined : __DEV__) === undefined) {
     console.log("production mode");
-    return ;
+    return;
   }
   
 }
diff --git a/jscomp/test/undef_regression_test.js b/jscomp/test/undef_regression_test.js
index 35ece56c42..814f0bcc0f 100644
--- a/jscomp/test/undef_regression_test.js
+++ b/jscomp/test/undef_regression_test.js
@@ -4,12 +4,12 @@
 
 function f(obj) {
   if (typeof obj === "function") {
-    return ;
+    return;
   }
   var size = obj.length;
   if (size !== undefined) {
     console.log(size);
-    return ;
+    return;
   }
   
 }
diff --git a/jscomp/test/unit_undefined_test.js b/jscomp/test/unit_undefined_test.js
index 4a43c971bb..7c555d8c6e 100644
--- a/jscomp/test/unit_undefined_test.js
+++ b/jscomp/test/unit_undefined_test.js
@@ -20,7 +20,7 @@ function f_01(param) {
   return hi(function (x) {
               if (x === undefined) {
                 console.log("x");
-                return ;
+                return;
               }
               
             });
diff --git a/lib/es6/arg.js b/lib/es6/arg.js
index ff03937e48..a4e741dcdc 100644
--- a/lib/es6/arg.js
+++ b/lib/es6/arg.js
@@ -124,7 +124,7 @@ function usage_b(buf, speclist, errmsg) {
   List.iter((function (param) {
           var doc = param[2];
           if (doc.length === 0) {
-            return ;
+            return;
           }
           var spec = param[1];
           var key = param[0];
@@ -157,7 +157,7 @@ function bool_of_string_opt(x) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Invalid_argument") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -170,7 +170,7 @@ function int_of_string_opt(x) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -183,7 +183,7 @@ function float_of_string_opt(x) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -279,7 +279,7 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
         var no_arg = (function(s,follow){
         return function no_arg(param) {
           if (follow === undefined) {
-            return ;
+            return;
           }
           throw {
                 RE_EXN_ID: Stop,
@@ -314,10 +314,10 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
         var consume_arg = (function(follow){
         return function consume_arg(param) {
           if (follow !== undefined) {
-            return ;
+            return;
           } else {
             current.contents = current.contents + 1 | 0;
-            return ;
+            return;
           }
         }
         }(follow));
@@ -347,11 +347,11 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
             case "Set" :
                 no_arg();
                 f._0.contents = true;
-                return ;
+                return;
             case "Clear" :
                 no_arg();
                 f._0.contents = false;
-                return ;
+                return;
             case "String" :
                 var arg$1 = get_arg();
                 Curry._1(f._0, arg$1);
@@ -456,7 +456,7 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
                   Curry._1(f$1, Caml_array.get(argv.contents, current.contents + 1 | 0));
                   consume_arg();
                 };
-                return ;
+                return;
             case "Expand" :
                 if (!allow_expand) {
                   throw {
@@ -480,7 +480,7 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
                         }
                       }
                     });
-                return ;
+                return;
             
           }
         }
diff --git a/lib/es6/array.js b/lib/es6/array.js
index c829e0d337..34f0073e58 100644
--- a/lib/es6/array.js
+++ b/lib/es6/array.js
@@ -395,7 +395,7 @@ function sort(cmp, a) {
     trickleup(bubble(i$1, 0), e);
   }
   if (l <= 1) {
-    return ;
+    return;
   }
   var e$1 = Caml_array.get(a, 1);
   Caml_array.set(a, 1, Caml_array.get(a, 0));
diff --git a/lib/es6/arrayLabels.js b/lib/es6/arrayLabels.js
index 338deb3dee..f861857f52 100644
--- a/lib/es6/arrayLabels.js
+++ b/lib/es6/arrayLabels.js
@@ -395,7 +395,7 @@ function sort(cmp, a) {
     trickleup(bubble(i$1, 0), e);
   }
   if (l <= 1) {
-    return ;
+    return;
   }
   var e$1 = Caml_array.get(a, 1);
   Caml_array.set(a, 1, Caml_array.get(a, 0));
diff --git a/lib/es6/belt_Array.js b/lib/es6/belt_Array.js
index 258b2af1f3..ea3d9cc0cd 100644
--- a/lib/es6/belt_Array.js
+++ b/lib/es6/belt_Array.js
@@ -241,14 +241,14 @@ function sliceToEnd(a, offset) {
 
 function fill(a, offset, len, v) {
   if (len <= 0) {
-    return ;
+    return;
   }
   var lena = a.length;
   var ofs = offset < 0 ? Caml.int_max(lena + offset | 0, 0) : offset;
   var hasLen = lena - ofs | 0;
   var fillLength = hasLen < len ? hasLen : len;
   if (fillLength <= 0) {
-    return ;
+    return;
   }
   for(var i = ofs ,i_finish = ofs + fillLength | 0; i < i_finish; ++i){
     a[i] = v;
@@ -260,7 +260,7 @@ function blitUnsafe(a1, srcofs1, a2, srcofs2, blitLength) {
     for(var j = 0; j < blitLength; ++j){
       a2[j + srcofs2 | 0] = a1[j + srcofs1 | 0];
     }
-    return ;
+    return;
   }
   for(var j$1 = blitLength - 1 | 0; j$1 >= 0; --j$1){
     a2[j$1 + srcofs2 | 0] = a1[j$1 + srcofs1 | 0];
@@ -277,7 +277,7 @@ function blit(a1, ofs1, a2, ofs2, len) {
     for(var j = 0; j < blitLength; ++j){
       a2[j + srcofs2 | 0] = a1[j + srcofs1 | 0];
     }
-    return ;
+    return;
   }
   for(var j$1 = blitLength - 1 | 0; j$1 >= 0; --j$1){
     a2[j$1 + srcofs2 | 0] = a1[j$1 + srcofs1 | 0];
diff --git a/lib/es6/belt_Float.js b/lib/es6/belt_Float.js
index 11b32ffb32..8ace73c859 100644
--- a/lib/es6/belt_Float.js
+++ b/lib/es6/belt_Float.js
@@ -4,7 +4,7 @@
 function fromString(i) {
   var i$1 = parseFloat(i);
   if (isNaN(i$1)) {
-    return ;
+    return;
   } else {
     return i$1;
   }
diff --git a/lib/es6/belt_HashMap.js b/lib/es6/belt_HashMap.js
index 5f125958d8..033352d046 100644
--- a/lib/es6/belt_HashMap.js
+++ b/lib/es6/belt_HashMap.js
@@ -12,7 +12,7 @@ function copyBucketReHash(hash, h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = hash(old_bucket.key) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -71,7 +71,7 @@ function set0(h, key, value, eq, hash) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -86,7 +86,7 @@ function set0(h, key, value, eq, hash) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
@@ -100,13 +100,13 @@ function remove(h, key) {
   var i = h.hash(key) & (h_buckets.length - 1 | 0);
   var bucket = h_buckets[i];
   if (bucket === undefined) {
-    return ;
+    return;
   }
   var eq = h.eq;
   if (eq(bucket.key, key)) {
     h_buckets[i] = bucket.next;
     h.size = h.size - 1 | 0;
-    return ;
+    return;
   } else {
     var _prec = bucket;
     var _bucket = bucket.next;
@@ -114,13 +114,13 @@ function remove(h, key) {
       var bucket$1 = _bucket;
       var prec = _prec;
       if (bucket$1 === undefined) {
-        return ;
+        return;
       }
       var cell_next = bucket$1.next;
       if (eq(bucket$1.key, key)) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       _bucket = cell_next;
       _prec = bucket$1;
@@ -134,7 +134,7 @@ function get(h, key) {
   var nid = h.hash(key) & (h_buckets.length - 1 | 0);
   var cell1 = h_buckets[nid];
   if (cell1 === undefined) {
-    return ;
+    return;
   }
   var eq = h.eq;
   if (eq(key, cell1.key)) {
@@ -142,7 +142,7 @@ function get(h, key) {
   }
   var cell2 = cell1.next;
   if (cell2 === undefined) {
-    return ;
+    return;
   }
   if (eq(key, cell2.key)) {
     return Caml_option.some(cell2.value);
@@ -156,7 +156,7 @@ function get(h, key) {
       while(true) {
         var buckets = _buckets;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         if (eq(key, buckets.key)) {
           return Caml_option.some(buckets.value);
diff --git a/lib/es6/belt_HashMapInt.js b/lib/es6/belt_HashMapInt.js
index ddf557c11e..289a8f6c02 100644
--- a/lib/es6/belt_HashMapInt.js
+++ b/lib/es6/belt_HashMapInt.js
@@ -9,7 +9,7 @@ function copyBucketReHash(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -68,7 +68,7 @@ function set(h, key, value) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -83,7 +83,7 @@ function set(h, key, value) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
@@ -96,7 +96,7 @@ function remove(h, key) {
     if (bucket.key === key) {
       h_buckets[i] = bucket.next;
       h.size = h.size - 1 | 0;
-      return ;
+      return;
     } else {
       var _prec = bucket;
       var _buckets = bucket.next;
@@ -104,13 +104,13 @@ function remove(h, key) {
         var buckets = _buckets;
         var prec = _prec;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         var cell_next = buckets.next;
         if (buckets.key === key) {
           prec.next = cell_next;
           h.size = h.size - 1 | 0;
-          return ;
+          return;
         }
         _buckets = cell_next;
         _prec = buckets;
@@ -126,14 +126,14 @@ function get(h, key) {
   var nid = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, key)) & (h_buckets.length - 1 | 0);
   var cell1 = h_buckets[nid];
   if (cell1 === undefined) {
-    return ;
+    return;
   }
   if (key === cell1.key) {
     return Caml_option.some(cell1.value);
   }
   var cell2 = cell1.next;
   if (cell2 === undefined) {
-    return ;
+    return;
   }
   if (key === cell2.key) {
     return Caml_option.some(cell2.value);
@@ -147,7 +147,7 @@ function get(h, key) {
       while(true) {
         var buckets = _buckets;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         if (key === buckets.key) {
           return Caml_option.some(buckets.value);
diff --git a/lib/es6/belt_HashMapString.js b/lib/es6/belt_HashMapString.js
index f9d1f94d0b..f976aaabf1 100644
--- a/lib/es6/belt_HashMapString.js
+++ b/lib/es6/belt_HashMapString.js
@@ -9,7 +9,7 @@ function copyBucketReHash(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -68,7 +68,7 @@ function set(h, key, value) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -83,7 +83,7 @@ function set(h, key, value) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
@@ -96,7 +96,7 @@ function remove(h, key) {
     if (bucket.key === key) {
       h_buckets[i] = bucket.next;
       h.size = h.size - 1 | 0;
-      return ;
+      return;
     } else {
       var _prec = bucket;
       var _buckets = bucket.next;
@@ -104,13 +104,13 @@ function remove(h, key) {
         var buckets = _buckets;
         var prec = _prec;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         var cell_next = buckets.next;
         if (buckets.key === key) {
           prec.next = cell_next;
           h.size = h.size - 1 | 0;
-          return ;
+          return;
         }
         _buckets = cell_next;
         _prec = buckets;
@@ -126,14 +126,14 @@ function get(h, key) {
   var nid = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, key)) & (h_buckets.length - 1 | 0);
   var cell1 = h_buckets[nid];
   if (cell1 === undefined) {
-    return ;
+    return;
   }
   if (key === cell1.key) {
     return Caml_option.some(cell1.value);
   }
   var cell2 = cell1.next;
   if (cell2 === undefined) {
-    return ;
+    return;
   }
   if (key === cell2.key) {
     return Caml_option.some(cell2.value);
@@ -147,7 +147,7 @@ function get(h, key) {
       while(true) {
         var buckets = _buckets;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         if (key === buckets.key) {
           return Caml_option.some(buckets.value);
diff --git a/lib/es6/belt_HashSet.js b/lib/es6/belt_HashSet.js
index f7d595005d..86c4ddb87a 100644
--- a/lib/es6/belt_HashSet.js
+++ b/lib/es6/belt_HashSet.js
@@ -7,7 +7,7 @@ function copyBucket(hash, h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = hash(old_bucket.key) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -28,13 +28,13 @@ function remove(h, key) {
   var i = h.hash(key) & (h_buckets.length - 1 | 0);
   var l = h_buckets[i];
   if (l === undefined) {
-    return ;
+    return;
   }
   var next_cell = l.next;
   if (eq(l.key, key)) {
     h.size = h.size - 1 | 0;
     h_buckets[i] = next_cell;
-    return ;
+    return;
   } else if (next_cell !== undefined) {
     var _prec = l;
     var _cell = next_cell;
@@ -45,17 +45,17 @@ function remove(h, key) {
       if (eq(cell.key, key)) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       if (cell_next === undefined) {
-        return ;
+        return;
       }
       _cell = cell_next;
       _prec = cell;
       continue ;
     };
   } else {
-    return ;
+    return;
   }
 }
 
@@ -63,7 +63,7 @@ function addBucket(h, key, _cell, eq) {
   while(true) {
     var cell = _cell;
     if (eq(cell.key, key)) {
-      return ;
+      return;
     }
     var n = cell.next;
     if (n !== undefined) {
@@ -75,7 +75,7 @@ function addBucket(h, key, _cell, eq) {
       key: key,
       next: undefined
     };
-    return ;
+    return;
   };
 }
 
@@ -98,7 +98,7 @@ function add0(h, key, hash, eq) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -113,7 +113,7 @@ function add0(h, key, hash, eq) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_HashSetInt.js b/lib/es6/belt_HashSetInt.js
index 5808c489ae..c5cba094a1 100644
--- a/lib/es6/belt_HashSetInt.js
+++ b/lib/es6/belt_HashSetInt.js
@@ -8,7 +8,7 @@ function copyBucket(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -28,13 +28,13 @@ function remove(h, key) {
   var i = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, key)) & (h_buckets.length - 1 | 0);
   var l = h_buckets[i];
   if (l === undefined) {
-    return ;
+    return;
   }
   var next_cell = l.next;
   if (l.key === key) {
     h.size = h.size - 1 | 0;
     h_buckets[i] = next_cell;
-    return ;
+    return;
   } else if (next_cell !== undefined) {
     var _prec = l;
     var _cell = next_cell;
@@ -45,17 +45,17 @@ function remove(h, key) {
       if (cell.key === key) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       if (cell_next === undefined) {
-        return ;
+        return;
       }
       _cell = cell_next;
       _prec = cell;
       continue ;
     };
   } else {
-    return ;
+    return;
   }
 }
 
@@ -63,7 +63,7 @@ function addBucket(h, key, _cell) {
   while(true) {
     var cell = _cell;
     if (cell.key === key) {
-      return ;
+      return;
     }
     var n = cell.next;
     if (n !== undefined) {
@@ -75,7 +75,7 @@ function addBucket(h, key, _cell) {
       key: key,
       next: undefined
     };
-    return ;
+    return;
   };
 }
 
@@ -98,7 +98,7 @@ function add(h, key) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -113,7 +113,7 @@ function add(h, key) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_HashSetString.js b/lib/es6/belt_HashSetString.js
index c5440a03ec..6da55844cf 100644
--- a/lib/es6/belt_HashSetString.js
+++ b/lib/es6/belt_HashSetString.js
@@ -8,7 +8,7 @@ function copyBucket(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -28,13 +28,13 @@ function remove(h, key) {
   var i = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, key)) & (h_buckets.length - 1 | 0);
   var l = h_buckets[i];
   if (l === undefined) {
-    return ;
+    return;
   }
   var next_cell = l.next;
   if (l.key === key) {
     h.size = h.size - 1 | 0;
     h_buckets[i] = next_cell;
-    return ;
+    return;
   } else if (next_cell !== undefined) {
     var _prec = l;
     var _cell = next_cell;
@@ -45,17 +45,17 @@ function remove(h, key) {
       if (cell.key === key) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       if (cell_next === undefined) {
-        return ;
+        return;
       }
       _cell = cell_next;
       _prec = cell;
       continue ;
     };
   } else {
-    return ;
+    return;
   }
 }
 
@@ -63,7 +63,7 @@ function addBucket(h, key, _cell) {
   while(true) {
     var cell = _cell;
     if (cell.key === key) {
-      return ;
+      return;
     }
     var n = cell.next;
     if (n !== undefined) {
@@ -75,7 +75,7 @@ function addBucket(h, key, _cell) {
       key: key,
       next: undefined
     };
-    return ;
+    return;
   };
 }
 
@@ -98,7 +98,7 @@ function add(h, key) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -113,7 +113,7 @@ function add(h, key) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_Int.js b/lib/es6/belt_Int.js
index 22241cc533..014908fa13 100644
--- a/lib/es6/belt_Int.js
+++ b/lib/es6/belt_Int.js
@@ -4,7 +4,7 @@
 function fromString(i) {
   var i$1 = parseInt(i, 10);
   if (isNaN(i$1)) {
-    return ;
+    return;
   } else {
     return i$1;
   }
diff --git a/lib/es6/belt_List.js b/lib/es6/belt_List.js
index 4f869087f2..563234042e 100644
--- a/lib/es6/belt_List.js
+++ b/lib/es6/belt_List.js
@@ -48,7 +48,7 @@ function add(xs, x) {
 
 function get(x, n) {
   if (n < 0) {
-    return ;
+    return;
   } else {
     var _x = x;
     var _n = n;
@@ -56,7 +56,7 @@ function get(x, n) {
       var n$1 = _n;
       var x$1 = _x;
       if (!x$1) {
-        return ;
+        return;
       }
       if (n$1 === 0) {
         return Caml_option.some(x$1.hd);
@@ -101,7 +101,7 @@ function partitionAux(p, _cell, _precX, _precY) {
     var precX = _precX;
     var cell = _cell;
     if (!cell) {
-      return ;
+      return;
     }
     var t = cell.tl;
     var h = cell.hd;
@@ -128,7 +128,7 @@ function splitAux(_cell, _precX, _precY) {
     var precX = _precX;
     var cell = _cell;
     if (!cell) {
-      return ;
+      return;
     }
     var match = cell.hd;
     var nextA = {
@@ -171,7 +171,7 @@ function copyAuxWitFilter(f, _cellX, _prec) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var t = cellX.tl;
     var h = cellX.hd;
@@ -196,7 +196,7 @@ function copyAuxWithFilterIndex(f, _cellX, _prec, _i) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var t = cellX.tl;
     var h = cellX.hd;
@@ -222,7 +222,7 @@ function copyAuxWitFilterMap(f, _cellX, _prec) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var t = cellX.tl;
     var h = f(cellX.hd);
@@ -300,7 +300,7 @@ function copyAuxWithMap(_cellX, _prec, f) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var next = {
       hd: f(cellX.hd),
@@ -319,10 +319,10 @@ function zipAux(_cellX, _cellY, _prec) {
     var cellY = _cellY;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     if (!cellY) {
-      return ;
+      return;
     }
     var next = {
       hd: [
@@ -345,10 +345,10 @@ function copyAuxWithMap2(f, _cellX, _cellY, _prec) {
     var cellY = _cellY;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     if (!cellY) {
-      return ;
+      return;
     }
     var next = {
       hd: f(cellX.hd, cellY.hd),
@@ -368,7 +368,7 @@ function copyAuxWithMapI(f, _i, _cellX, _prec) {
     var cellX = _cellX;
     var i = _i;
     if (!cellX) {
-      return ;
+      return;
     }
     var next = {
       hd: f(i, cellX.hd),
@@ -414,7 +414,7 @@ function splitAtAux(_n, _cell, _prec) {
       return cell;
     }
     if (!cell) {
-      return ;
+      return;
     }
     var cell$1 = {
       hd: cell.hd,
@@ -430,13 +430,13 @@ function splitAtAux(_n, _cell, _prec) {
 
 function take(lst, n) {
   if (n < 0) {
-    return ;
+    return;
   }
   if (n === 0) {
     return /* [] */0;
   }
   if (!lst) {
-    return ;
+    return;
   }
   var cell = {
     hd: lst.hd,
@@ -451,7 +451,7 @@ function take(lst, n) {
 
 function drop(lst, n) {
   if (n < 0) {
-    return ;
+    return;
   } else {
     var _l = lst;
     var _n = n;
@@ -462,7 +462,7 @@ function drop(lst, n) {
         return l;
       }
       if (!l) {
-        return ;
+        return;
       }
       _n = n$1 - 1 | 0;
       _l = l.tl;
@@ -473,7 +473,7 @@ function drop(lst, n) {
 
 function splitAt(lst, n) {
   if (n < 0) {
-    return ;
+    return;
   }
   if (n === 0) {
     return [
@@ -482,7 +482,7 @@ function splitAt(lst, n) {
           ];
   }
   if (!lst) {
-    return ;
+    return;
   }
   var cell = {
     hd: lst.hd,
@@ -629,7 +629,7 @@ function fillAux(arr, _i, _x) {
     var x = _x;
     var i = _i;
     if (!x) {
-      return ;
+      return;
     }
     arr[i] = x.hd;
     _x = x.tl;
@@ -699,7 +699,7 @@ function flattenAux(_prec, _xs) {
       continue ;
     }
     prec.tl = /* [] */0;
-    return ;
+    return;
   };
 }
 
@@ -765,7 +765,7 @@ function forEachU(_xs, f) {
   while(true) {
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     f(xs.hd);
     _xs = xs.tl;
@@ -784,7 +784,7 @@ function forEachWithIndexU(l, f) {
     var i = _i;
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     f(i, xs.hd);
     _i = i + 1 | 0;
@@ -890,10 +890,10 @@ function forEach2U(_l1, _l2, f) {
     var l2 = _l2;
     var l1 = _l1;
     if (!l1) {
-      return ;
+      return;
     }
     if (!l2) {
-      return ;
+      return;
     }
     f(l1.hd, l2.hd);
     _l2 = l2.tl;
@@ -1128,7 +1128,7 @@ function getAssocU(_xs, x, eq) {
   while(true) {
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     var match = xs.hd;
     if (eq(match[0], x)) {
@@ -1243,7 +1243,7 @@ function getByU(_xs, p) {
   while(true) {
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     var x = xs.hd;
     if (p(x)) {
diff --git a/lib/es6/belt_MapDict.js b/lib/es6/belt_MapDict.js
index 7b7ad6bd66..d9dd10f98f 100644
--- a/lib/es6/belt_MapDict.js
+++ b/lib/es6/belt_MapDict.js
@@ -205,7 +205,7 @@ function mergeU(s1, s2, f, cmp) {
                     return f(k, undefined, Caml_option.some(v));
                   }));
     } else {
-      return ;
+      return;
     }
   }
   if (s2 === undefined) {
diff --git a/lib/es6/belt_MutableMap.js b/lib/es6/belt_MutableMap.js
index 554417dc0a..c74195e6e7 100644
--- a/lib/es6/belt_MutableMap.js
+++ b/lib/es6/belt_MutableMap.js
@@ -44,12 +44,12 @@ function removeMutateAux(nt, x, cmp) {
 function remove(d, k) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = removeMutateAux(oldRoot, k, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -64,7 +64,7 @@ function removeArrayMutateAux(_t, xs, _i, len, cmp) {
     var ele = xs[i];
     var u = removeMutateAux(t, ele, cmp);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -75,13 +75,13 @@ function removeArrayMutateAux(_t, xs, _i, len, cmp) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   var newRoot = removeArrayMutateAux(oldRoot, xs, 0, len, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -131,7 +131,7 @@ function updateU(t, x, f) {
   var newRoot = updateDone(oldRoot, x, f, t.cmp);
   if (newRoot !== oldRoot) {
     t.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -315,7 +315,7 @@ function set(m, e, v) {
   var newRoot = Belt_internalAVLtree.updateMutate(oldRoot, e, v, m.cmp);
   if (newRoot !== oldRoot) {
     m.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -334,7 +334,7 @@ function mergeMany(d, xs) {
   var newRoot = mergeManyAux(oldRoot, xs, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_MutableMapInt.js b/lib/es6/belt_MutableMapInt.js
index 267f2da81b..77fe903c3e 100644
--- a/lib/es6/belt_MutableMapInt.js
+++ b/lib/es6/belt_MutableMapInt.js
@@ -57,7 +57,7 @@ function set(m, k, v) {
   var v$1 = Belt_internalMapInt.addMutate(old_data, k, v);
   if (v$1 !== old_data) {
     m.data = v$1;
-    return ;
+    return;
   }
   
 }
@@ -179,12 +179,12 @@ function removeMutateAux(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = removeMutateAux(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -234,7 +234,7 @@ function updateU(t, x, f) {
   var newRoot = updateDone(oldRoot, x, f);
   if (newRoot !== oldRoot) {
     t.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -253,7 +253,7 @@ function removeArrayMutateAux(_t, xs, _i, len) {
     var ele = xs[i];
     var u = removeMutateAux(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -264,13 +264,13 @@ function removeArrayMutateAux(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   var newRoot = removeArrayMutateAux(oldRoot, xs, 0, len);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_MutableMapString.js b/lib/es6/belt_MutableMapString.js
index f3d2ac6c0e..c70a373985 100644
--- a/lib/es6/belt_MutableMapString.js
+++ b/lib/es6/belt_MutableMapString.js
@@ -57,7 +57,7 @@ function set(m, k, v) {
   var v$1 = Belt_internalMapString.addMutate(old_data, k, v);
   if (v$1 !== old_data) {
     m.data = v$1;
-    return ;
+    return;
   }
   
 }
@@ -179,12 +179,12 @@ function removeMutateAux(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = removeMutateAux(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -234,7 +234,7 @@ function updateU(t, x, f) {
   var newRoot = updateDone(oldRoot, x, f);
   if (newRoot !== oldRoot) {
     t.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -253,7 +253,7 @@ function removeArrayMutateAux(_t, xs, _i, len) {
     var ele = xs[i];
     var u = removeMutateAux(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -264,13 +264,13 @@ function removeArrayMutateAux(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   var newRoot = removeArrayMutateAux(oldRoot, xs, 0, len);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_MutableQueue.js b/lib/es6/belt_MutableQueue.js
index 55ee11cc18..a28f4ae9fa 100644
--- a/lib/es6/belt_MutableQueue.js
+++ b/lib/es6/belt_MutableQueue.js
@@ -64,7 +64,7 @@ function peekExn(q) {
 function pop(q) {
   var x = q.first;
   if (x === undefined) {
-    return ;
+    return;
   }
   var next = x.next;
   if (next === undefined) {
@@ -99,7 +99,7 @@ function popExn(q) {
 function popUndefined(q) {
   var x = q.first;
   if (x === undefined) {
-    return ;
+    return;
   }
   var next = x.next;
   if (next === undefined) {
@@ -191,7 +191,7 @@ function forEachU(q, f) {
   while(true) {
     var cell = _cell;
     if (cell === undefined) {
-      return ;
+      return;
     }
     f(cell.content);
     _cell = cell.next;
@@ -225,7 +225,7 @@ function reduce(q, accu, f) {
 
 function transfer(q1, q2) {
   if (q1.length <= 0) {
-    return ;
+    return;
   }
   var l = q2.last;
   if (l !== undefined) {
@@ -246,7 +246,7 @@ function fillAux(_i, arr, _cell) {
     var cell = _cell;
     var i = _i;
     if (cell === undefined) {
-      return ;
+      return;
     }
     arr[i] = cell.content;
     _cell = cell.next;
diff --git a/lib/es6/belt_MutableSet.js b/lib/es6/belt_MutableSet.js
index 2059d44b97..f0c891cc2e 100644
--- a/lib/es6/belt_MutableSet.js
+++ b/lib/es6/belt_MutableSet.js
@@ -42,12 +42,12 @@ function remove0(nt, x, cmp) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = remove0(oldRoot, v, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -62,7 +62,7 @@ function removeMany0(_t, xs, _i, len, cmp) {
     var ele = xs[i];
     var u = remove0(t, ele, cmp);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -73,7 +73,7 @@ function removeMany0(_t, xs, _i, len, cmp) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   d.data = removeMany0(oldRoot, xs, 0, len, d.cmp);
@@ -168,7 +168,7 @@ function add(m, e) {
   var newRoot = Belt_internalAVLset.addMutate(m.cmp, oldRoot, e);
   if (newRoot !== oldRoot) {
     m.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_MutableSetInt.js b/lib/es6/belt_MutableSetInt.js
index ac71238867..645da29308 100644
--- a/lib/es6/belt_MutableSetInt.js
+++ b/lib/es6/belt_MutableSetInt.js
@@ -42,12 +42,12 @@ function remove0(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = remove0(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -62,7 +62,7 @@ function removeMany0(_t, xs, _i, len) {
     var ele = xs[i];
     var u = remove0(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -73,7 +73,7 @@ function removeMany0(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   d.data = removeMany0(oldRoot, xs, 0, len);
@@ -166,7 +166,7 @@ function add(d, k) {
   var v = Belt_internalSetInt.addMutate(oldRoot, k);
   if (v !== oldRoot) {
     d.data = v;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_MutableSetString.js b/lib/es6/belt_MutableSetString.js
index 4e95e87d62..eb81f96af2 100644
--- a/lib/es6/belt_MutableSetString.js
+++ b/lib/es6/belt_MutableSetString.js
@@ -42,12 +42,12 @@ function remove0(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = remove0(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -62,7 +62,7 @@ function removeMany0(_t, xs, _i, len) {
     var ele = xs[i];
     var u = remove0(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -73,7 +73,7 @@ function removeMany0(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   d.data = removeMany0(oldRoot, xs, 0, len);
@@ -166,7 +166,7 @@ function add(d, k) {
   var v = Belt_internalSetString.addMutate(oldRoot, k);
   if (v !== oldRoot) {
     d.data = v;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/es6/belt_MutableStack.js b/lib/es6/belt_MutableStack.js
index 79ccc949ab..fc09cfd9f9 100644
--- a/lib/es6/belt_MutableStack.js
+++ b/lib/es6/belt_MutableStack.js
@@ -90,7 +90,7 @@ function forEachU(s, f) {
   while(true) {
     var s$1 = _s;
     if (s$1 === undefined) {
-      return ;
+      return;
     }
     f(s$1.head);
     _s = s$1.tail;
@@ -106,7 +106,7 @@ function dynamicPopIterU(s, f) {
   while(true) {
     var match = s.root;
     if (match === undefined) {
-      return ;
+      return;
     }
     s.root = match.tail;
     f(match.head);
diff --git a/lib/es6/belt_SetDict.js b/lib/es6/belt_SetDict.js
index 723ff54bd7..4408f759f5 100644
--- a/lib/es6/belt_SetDict.js
+++ b/lib/es6/belt_SetDict.js
@@ -212,10 +212,10 @@ function union(s1, s2, cmp) {
 
 function intersect(s1, s2, cmp) {
   if (s1 === undefined) {
-    return ;
+    return;
   }
   if (s2 === undefined) {
-    return ;
+    return;
   }
   var v1 = s1.v;
   var l1 = s1.l;
diff --git a/lib/es6/belt_SetInt.js b/lib/es6/belt_SetInt.js
index 15fbe9cb76..62a0d62495 100644
--- a/lib/es6/belt_SetInt.js
+++ b/lib/es6/belt_SetInt.js
@@ -209,10 +209,10 @@ function union(s1, s2) {
 
 function intersect(s1, s2) {
   if (s1 === undefined) {
-    return ;
+    return;
   }
   if (s2 === undefined) {
-    return ;
+    return;
   }
   var v1 = s1.v;
   var l1 = s1.l;
diff --git a/lib/es6/belt_SetString.js b/lib/es6/belt_SetString.js
index 3cfe2c2586..186eb396ad 100644
--- a/lib/es6/belt_SetString.js
+++ b/lib/es6/belt_SetString.js
@@ -209,10 +209,10 @@ function union(s1, s2) {
 
 function intersect(s1, s2) {
   if (s1 === undefined) {
-    return ;
+    return;
   }
   if (s2 === undefined) {
-    return ;
+    return;
   }
   var v1 = s1.v;
   var l1 = s1.l;
diff --git a/lib/es6/belt_internalAVLset.js b/lib/es6/belt_internalAVLset.js
index cf4734c654..26a891a0b5 100644
--- a/lib/es6/belt_internalAVLset.js
+++ b/lib/es6/belt_internalAVLset.js
@@ -168,7 +168,7 @@ function forEachU(_n, f) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     forEachU(n.l, f);
     f(n.v);
@@ -360,7 +360,7 @@ function checkInvariantInternal(_v) {
   while(true) {
     var v = _v;
     if (v === undefined) {
-      return ;
+      return;
     }
     var l = v.l;
     var r = v.r;
@@ -424,7 +424,7 @@ function fillArrayWithPartition(_n, cursor, arr, p) {
       cursor.backward = c$1 - 1 | 0;
     }
     if (r === undefined) {
-      return ;
+      return;
     }
     _n = r;
     continue ;
@@ -462,7 +462,7 @@ function toArray(n) {
 function fromSortedArrayRevAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         return singleton(arr[off]);
     case 2 :
@@ -496,7 +496,7 @@ function fromSortedArrayRevAux(arr, off, len) {
 function fromSortedArrayAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         return singleton(arr[off]);
     case 2 :
@@ -533,7 +533,7 @@ function fromSortedArrayUnsafe(arr) {
 
 function keepSharedU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var v = n.v;
   var l = n.l;
@@ -558,7 +558,7 @@ function keepShared(n, p) {
 
 function keepCopyU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var size = lengthNode(n);
   var v = new Array(size);
@@ -692,7 +692,7 @@ function get(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     var c = cmp(x, v);
@@ -708,7 +708,7 @@ function getUndefined(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     var c = cmp(x, v);
@@ -856,7 +856,7 @@ function addMutate(cmp, t, x) {
 function fromArray(xs, cmp) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (x, y) {
           return cmp(x, y) < 0;
diff --git a/lib/es6/belt_internalAVLtree.js b/lib/es6/belt_internalAVLtree.js
index 966462c18c..e8be3b96a8 100644
--- a/lib/es6/belt_internalAVLtree.js
+++ b/lib/es6/belt_internalAVLtree.js
@@ -247,7 +247,7 @@ function stackAllLeft(_v, _s) {
 
 function findFirstByU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var left = findFirstByU(n.l, p);
   if (left !== undefined) {
@@ -277,7 +277,7 @@ function forEachU(_n, f) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     forEachU(n.l, f);
     f(n.k, n.v);
@@ -292,7 +292,7 @@ function forEach(n, f) {
 
 function mapU(n, f) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var newLeft = mapU(n.l, f);
   var newD = f(n.v);
@@ -312,7 +312,7 @@ function map(n, f) {
 
 function mapWithKeyU(n, f) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var key = n.k;
   var newLeft = mapWithKeyU(n.l, f);
@@ -463,7 +463,7 @@ function concatOrJoin(t1, v, d, t2) {
 
 function keepSharedU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var v = n.k;
   var d = n.v;
@@ -483,7 +483,7 @@ function keepShared(n, p) {
 
 function keepMapU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var v = n.k;
   var d = n.v;
@@ -581,7 +581,7 @@ function checkInvariantInternal(_v) {
   while(true) {
     var v = _v;
     if (v === undefined) {
-      return ;
+      return;
     }
     var l = v.l;
     var r = v.r;
@@ -695,7 +695,7 @@ function valuesToArray(n) {
 function fromSortedArrayRevAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         var match = arr[off];
         return singleton(match[0], match[1]);
@@ -737,7 +737,7 @@ function fromSortedArrayRevAux(arr, off, len) {
 function fromSortedArrayAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         var match = arr[off];
         return singleton(match[0], match[1]);
@@ -857,7 +857,7 @@ function get(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     var c = cmp(x, v);
@@ -873,7 +873,7 @@ function getUndefined(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     var c = cmp(x, v);
@@ -1046,7 +1046,7 @@ function updateMutate(t, x, data, cmp) {
 function fromArray(xs, cmp) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (param, param$1) {
           return cmp(param[0], param$1[0]) < 0;
diff --git a/lib/es6/belt_internalBuckets.js b/lib/es6/belt_internalBuckets.js
index 5cf1f42213..2b2e7bf6b5 100644
--- a/lib/es6/belt_internalBuckets.js
+++ b/lib/es6/belt_internalBuckets.js
@@ -22,7 +22,7 @@ function copyAuxCont(_c, _prec) {
     var prec = _prec;
     var c = _c;
     if (c === undefined) {
-      return ;
+      return;
     }
     var ncopy = {
       key: c.key,
@@ -71,7 +71,7 @@ function do_bucket_iter(f, _buckets) {
   while(true) {
     var buckets = _buckets;
     if (buckets === undefined) {
-      return ;
+      return;
     }
     f(buckets.key, buckets.value);
     _buckets = buckets.next;
@@ -163,7 +163,7 @@ function filterMapInplaceBucket(f, h, i, _prec, _cell) {
       cell.value = Caml_option.valFromOption(data);
       if (n === undefined) {
         cell.next = n;
-        return ;
+        return;
       }
       _cell = n;
       _prec = cell;
@@ -176,7 +176,7 @@ function filterMapInplaceBucket(f, h, i, _prec, _cell) {
       } else {
         h.buckets[i] = prec;
       }
-      return ;
+      return;
     }
     _cell = n;
     continue ;
diff --git a/lib/es6/belt_internalMapInt.js b/lib/es6/belt_internalMapInt.js
index 75c851cc30..68b22e84dc 100644
--- a/lib/es6/belt_internalMapInt.js
+++ b/lib/es6/belt_internalMapInt.js
@@ -26,7 +26,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -41,7 +41,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -198,7 +198,7 @@ function mergeU(s1, s2, f) {
     }
     
   } else if (s2 === undefined) {
-    return ;
+    return;
   }
   var v2 = s2.k;
   var d2 = s2.v;
@@ -313,7 +313,7 @@ function addMutate(t, x, data) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (param, param$1) {
           return param[0] < param$1[0];
diff --git a/lib/es6/belt_internalMapString.js b/lib/es6/belt_internalMapString.js
index 26a3e7dd0b..d2f0e913b7 100644
--- a/lib/es6/belt_internalMapString.js
+++ b/lib/es6/belt_internalMapString.js
@@ -26,7 +26,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -41,7 +41,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -198,7 +198,7 @@ function mergeU(s1, s2, f) {
     }
     
   } else if (s2 === undefined) {
-    return ;
+    return;
   }
   var v2 = s2.k;
   var d2 = s2.v;
@@ -313,7 +313,7 @@ function addMutate(t, x, data) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (param, param$1) {
           return param[0] < param$1[0];
diff --git a/lib/es6/belt_internalSetBuckets.js b/lib/es6/belt_internalSetBuckets.js
index 1677ce3f41..c70aa987d1 100644
--- a/lib/es6/belt_internalSetBuckets.js
+++ b/lib/es6/belt_internalSetBuckets.js
@@ -8,7 +8,7 @@ function copyAuxCont(_c, _prec) {
     var prec = _prec;
     var c = _c;
     if (c === undefined) {
-      return ;
+      return;
     }
     var ncopy = {
       key: c.key,
@@ -68,7 +68,7 @@ function doBucketIter(f, _buckets) {
   while(true) {
     var buckets = _buckets;
     if (buckets === undefined) {
-      return ;
+      return;
     }
     f(buckets.key);
     _buckets = buckets.next;
diff --git a/lib/es6/belt_internalSetInt.js b/lib/es6/belt_internalSetInt.js
index 5403be7121..65e3fe2d09 100644
--- a/lib/es6/belt_internalSetInt.js
+++ b/lib/es6/belt_internalSetInt.js
@@ -104,7 +104,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -119,7 +119,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -169,7 +169,7 @@ function addMutate(t, x) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArrayInt.strictlySortedLength(xs);
   var result;
diff --git a/lib/es6/belt_internalSetString.js b/lib/es6/belt_internalSetString.js
index 0afe623cc4..12c039d35b 100644
--- a/lib/es6/belt_internalSetString.js
+++ b/lib/es6/belt_internalSetString.js
@@ -104,7 +104,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -119,7 +119,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -169,7 +169,7 @@ function addMutate(t, x) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArrayString.strictlySortedLength(xs);
   var result;
diff --git a/lib/es6/buffer.js b/lib/es6/buffer.js
index fa1e3efbfa..21b3181a2a 100644
--- a/lib/es6/buffer.js
+++ b/lib/es6/buffer.js
@@ -117,7 +117,7 @@ function add_utf_8_uchar(b, u) {
     b.buffer[pos] = 192 | (u$1 >>> 6);
     b.buffer[pos + 1 | 0] = 128 | u$1 & 63;
     b.position = pos + 2 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 65535) {
     var pos$1 = b.position;
@@ -128,7 +128,7 @@ function add_utf_8_uchar(b, u) {
     b.buffer[pos$1 + 1 | 0] = 128 | (u$1 >>> 6) & 63;
     b.buffer[pos$1 + 2 | 0] = 128 | u$1 & 63;
     b.position = pos$1 + 3 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 1114111) {
     var pos$2 = b.position;
@@ -140,7 +140,7 @@ function add_utf_8_uchar(b, u) {
     b.buffer[pos$2 + 2 | 0] = 128 | (u$1 >>> 6) & 63;
     b.buffer[pos$2 + 3 | 0] = 128 | u$1 & 63;
     b.position = pos$2 + 4 | 0;
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -174,7 +174,7 @@ function add_utf_16be_uchar(b, u) {
     b.buffer[pos] = (u$1 >>> 8);
     b.buffer[pos + 1 | 0] = u$1 & 255;
     b.position = pos + 2 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 1114111) {
     var u$p = u$1 - 65536 | 0;
@@ -189,7 +189,7 @@ function add_utf_16be_uchar(b, u) {
     b.buffer[pos$1 + 2 | 0] = (lo >>> 8);
     b.buffer[pos$1 + 3 | 0] = lo & 255;
     b.position = pos$1 + 4 | 0;
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -223,7 +223,7 @@ function add_utf_16le_uchar(b, u) {
     b.buffer[pos] = u$1 & 255;
     b.buffer[pos + 1 | 0] = (u$1 >>> 8);
     b.position = pos + 2 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 1114111) {
     var u$p = u$1 - 65536 | 0;
@@ -238,7 +238,7 @@ function add_utf_16le_uchar(b, u) {
     b.buffer[pos$1 + 2 | 0] = lo & 255;
     b.buffer[pos$1 + 3 | 0] = (lo >>> 8);
     b.position = pos$1 + 4 | 0;
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -404,7 +404,7 @@ function add_substitute(b, f, s) {
       if (previous === /* '\\' */92) {
         return add_char(b, previous);
       } else {
-        return ;
+        return;
       }
     }
     var current = Caml_string.get(s, i);
diff --git a/lib/es6/bytes.js b/lib/es6/bytes.js
index 579cdf7069..d09948f76e 100644
--- a/lib/es6/bytes.js
+++ b/lib/es6/bytes.js
@@ -8,7 +8,7 @@ import * as Caml_js_exceptions from "./caml_js_exceptions.js";
 
 function unsafe_fill(s, i, l, c) {
   if (l <= 0) {
-    return ;
+    return;
   }
   for(var k = i ,k_finish = l + i | 0; k < k_finish; ++k){
     s[k] = c;
@@ -17,7 +17,7 @@ function unsafe_fill(s, i, l, c) {
 
 function unsafe_blit(s1, i1, s2, i2, len) {
   if (len <= 0) {
-    return ;
+    return;
   }
   if (s1 === s2) {
     if (i1 < i2) {
@@ -27,10 +27,10 @@ function unsafe_blit(s1, i1, s2, i2, len) {
       for(var j = range; j >= 0; --j){
         s1[i2 + j | 0] = s1[i1 + j | 0];
       }
-      return ;
+      return;
     }
     if (i1 <= i2) {
-      return ;
+      return;
     }
     var range_a$1 = (s1.length - i1 | 0) - 1 | 0;
     var range_b$1 = len - 1 | 0;
@@ -38,14 +38,14 @@ function unsafe_blit(s1, i1, s2, i2, len) {
     for(var k = 0; k <= range$1; ++k){
       s1[i2 + k | 0] = s1[i1 + k | 0];
     }
-    return ;
+    return;
   }
   var off1 = s1.length - i1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[i2 + i | 0] = s1[i1 + i | 0];
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[i2 + i$1 | 0] = s1[i1 + i$1 | 0];
@@ -207,14 +207,14 @@ function blit_string(s1, ofs1, s2, ofs2, len) {
         };
   }
   if (len <= 0) {
-    return ;
+    return;
   }
   var off1 = s1.length - ofs1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[ofs2 + i | 0] = s1.codePointAt(ofs1 + i | 0);
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[ofs2 + i$1 | 0] = s1.codePointAt(ofs1 + i$1 | 0);
@@ -506,7 +506,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
@@ -580,7 +580,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
diff --git a/lib/es6/bytesLabels.js b/lib/es6/bytesLabels.js
index 579cdf7069..d09948f76e 100644
--- a/lib/es6/bytesLabels.js
+++ b/lib/es6/bytesLabels.js
@@ -8,7 +8,7 @@ import * as Caml_js_exceptions from "./caml_js_exceptions.js";
 
 function unsafe_fill(s, i, l, c) {
   if (l <= 0) {
-    return ;
+    return;
   }
   for(var k = i ,k_finish = l + i | 0; k < k_finish; ++k){
     s[k] = c;
@@ -17,7 +17,7 @@ function unsafe_fill(s, i, l, c) {
 
 function unsafe_blit(s1, i1, s2, i2, len) {
   if (len <= 0) {
-    return ;
+    return;
   }
   if (s1 === s2) {
     if (i1 < i2) {
@@ -27,10 +27,10 @@ function unsafe_blit(s1, i1, s2, i2, len) {
       for(var j = range; j >= 0; --j){
         s1[i2 + j | 0] = s1[i1 + j | 0];
       }
-      return ;
+      return;
     }
     if (i1 <= i2) {
-      return ;
+      return;
     }
     var range_a$1 = (s1.length - i1 | 0) - 1 | 0;
     var range_b$1 = len - 1 | 0;
@@ -38,14 +38,14 @@ function unsafe_blit(s1, i1, s2, i2, len) {
     for(var k = 0; k <= range$1; ++k){
       s1[i2 + k | 0] = s1[i1 + k | 0];
     }
-    return ;
+    return;
   }
   var off1 = s1.length - i1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[i2 + i | 0] = s1[i1 + i | 0];
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[i2 + i$1 | 0] = s1[i1 + i$1 | 0];
@@ -207,14 +207,14 @@ function blit_string(s1, ofs1, s2, ofs2, len) {
         };
   }
   if (len <= 0) {
-    return ;
+    return;
   }
   var off1 = s1.length - ofs1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[ofs2 + i | 0] = s1.codePointAt(ofs1 + i | 0);
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[ofs2 + i$1 | 0] = s1.codePointAt(ofs1 + i$1 | 0);
@@ -506,7 +506,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
@@ -580,7 +580,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
diff --git a/lib/es6/caml_array.js b/lib/es6/caml_array.js
index 5387a200c7..fc57597f7d 100644
--- a/lib/es6/caml_array.js
+++ b/lib/es6/caml_array.js
@@ -31,7 +31,7 @@ function fill(arr, _i, _l) {
     var l = _l;
     var i = _i;
     if (!l) {
-      return ;
+      return;
     }
     var x = l.hd;
     var l$1 = x.length;
@@ -98,7 +98,7 @@ function blit(a1, i1, a2, i2, len) {
     for(var j = 0; j < len; ++j){
       a2[j + i2 | 0] = a1[j + i1 | 0];
     }
-    return ;
+    return;
   }
   for(var j$1 = len - 1 | 0; j$1 >= 0; --j$1){
     a2[j$1 + i2 | 0] = a1[j$1 + i1 | 0];
diff --git a/lib/es6/caml_module.js b/lib/es6/caml_module.js
index 93cd8ad219..09b215bca0 100644
--- a/lib/es6/caml_module.js
+++ b/lib/es6/caml_module.js
@@ -16,7 +16,7 @@ function init_mod(loc, shape) {
         case "Function" :
         case "Lazy" :
             struct_[idx] = undef_module;
-            return ;
+            return;
         case "Class" :
             struct_[idx] = [
               undef_module,
@@ -24,7 +24,7 @@ function init_mod(loc, shape) {
               undef_module,
               0
             ];
-            return ;
+            return;
         
       }
     } else {
@@ -37,10 +37,10 @@ function init_mod(loc, shape) {
           var match = comps[i];
           loop(match[0], v, match[1]);
         }
-        return ;
+        return;
       }
       struct_[idx] = shape._0;
-      return ;
+      return;
     }
   };
   var res = {};
@@ -55,7 +55,7 @@ function update_mod(shape, o, n) {
       switch (shape) {
         case "Function" :
             parent[i] = n;
-            return ;
+            return;
         case "Lazy" :
         case "Class" :
             return Caml_obj.update_dummy(o, n);
@@ -63,7 +63,7 @@ function update_mod(shape, o, n) {
       }
     } else {
       if (shape.TAG !== "Module") {
-        return ;
+        return;
       }
       var comps = shape._0;
       for(var i$1 = 0 ,i_finish = comps.length; i$1 < i_finish; ++i$1){
@@ -71,7 +71,7 @@ function update_mod(shape, o, n) {
         var name = match[1];
         aux(match[0], o[name], n[name], o, name);
       }
-      return ;
+      return;
     }
   };
   if (typeof shape !== "object") {
@@ -92,7 +92,7 @@ function update_mod(shape, o, n) {
       var name = match[1];
       aux(match[0], o[name], n[name], o, name);
     }
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
diff --git a/lib/es6/caml_obj.js b/lib/es6/caml_obj.js
index 7cc1fff7ef..53f1fb966c 100644
--- a/lib/es6/caml_obj.js
+++ b/lib/es6/caml_obj.js
@@ -215,14 +215,14 @@ function aux_obj_compare(a, b) {
     var min_key = param[2];
     var b = param[1];
     if (!(!Object.prototype.hasOwnProperty.call(b, key) || compare(param[0][key], b[key]) > 0)) {
-      return ;
+      return;
     }
     var mk = min_key.contents;
     if (mk !== undefined && key >= mk) {
-      return ;
+      return;
     } else {
       min_key.contents = key;
-      return ;
+      return;
     }
   };
   var partial_arg = [
@@ -317,14 +317,14 @@ function equal(a, b) {
       var do_key_a = function (key) {
         if (!Object.prototype.hasOwnProperty.call(b, key)) {
           result.contents = false;
-          return ;
+          return;
         }
         
       };
       var do_key_b = function (key) {
         if (!Object.prototype.hasOwnProperty.call(a, key) || !equal(b[key], a[key])) {
           result.contents = false;
-          return ;
+          return;
         }
         
       };
diff --git a/lib/es6/caml_option.js b/lib/es6/caml_option.js
index e88e767349..2aa092c71f 100644
--- a/lib/es6/caml_option.js
+++ b/lib/es6/caml_option.js
@@ -21,7 +21,7 @@ function some(x) {
 
 function nullable_to_opt(x) {
   if (x == null) {
-    return ;
+    return;
   } else {
     return some(x);
   }
@@ -29,7 +29,7 @@ function nullable_to_opt(x) {
 
 function undefined_to_opt(x) {
   if (x === undefined) {
-    return ;
+    return;
   } else {
     return some(x);
   }
@@ -37,7 +37,7 @@ function undefined_to_opt(x) {
 
 function null_to_opt(x) {
   if (x === null) {
-    return ;
+    return;
   } else {
     return some(x);
   }
@@ -49,7 +49,7 @@ function valFromOption(x) {
   }
   var depth = x.BS_PRIVATE_NESTED_SOME_NONE;
   if (depth === 0) {
-    return ;
+    return;
   } else {
     return {
             BS_PRIVATE_NESTED_SOME_NONE: depth - 1 | 0
@@ -59,7 +59,7 @@ function valFromOption(x) {
 
 function option_get(x) {
   if (x === undefined) {
-    return ;
+    return;
   } else {
     return valFromOption(x);
   }
diff --git a/lib/es6/genlex.js b/lib/es6/genlex.js
index 5672c5817a..c74735e641 100644
--- a/lib/es6/genlex.js
+++ b/lib/es6/genlex.js
@@ -85,7 +85,7 @@ function make_lexer(keywords) {
     while(true) {
       var c = Stream.peek(strm__);
       if (c === undefined) {
-        return ;
+        return;
       }
       var exit = 0;
       if (c < 124) {
@@ -622,7 +622,7 @@ function make_lexer(keywords) {
                     continue ;
                   }
                   Stream.junk(strm__);
-                  return ;
+                  return;
                 }
                 throw {
                       RE_EXN_ID: Stream.Failure,
diff --git a/lib/es6/hashtbl.js b/lib/es6/hashtbl.js
index e0ed48cdd3..504173182f 100644
--- a/lib/es6/hashtbl.js
+++ b/lib/es6/hashtbl.js
@@ -84,7 +84,7 @@ function reset(h) {
   } else {
     h.size = 0;
     h.data = Caml_array.make(Pervasives.abs(h.initial_size), "Empty");
-    return ;
+    return;
   }
 }
 
@@ -100,7 +100,7 @@ function copy_bucketlist(param) {
       var param = _param;
       var prec = _prec;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var key = param.key;
       var data = param.data;
@@ -156,7 +156,7 @@ function resize(indexfun, h) {
   var osize = odata.length;
   var nsize = (osize << 1);
   if (nsize < osize) {
-    return ;
+    return;
   }
   var ndata = Caml_array.make(nsize, "Empty");
   var ndata_tail = Caml_array.make(nsize, "Empty");
@@ -166,7 +166,7 @@ function resize(indexfun, h) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var key = param.key;
       var data = param.data;
@@ -193,7 +193,7 @@ function resize(indexfun, h) {
     insert_bucket(Caml_array.get(odata, i));
   }
   if (!inplace) {
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < nsize; ++i$1){
     var tail = Caml_array.get(ndata_tail, i$1);
@@ -232,7 +232,7 @@ function remove(h, key) {
     var param = _param;
     var prec = _prec;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var k = param.key;
     var next = param.next;
@@ -242,7 +242,7 @@ function remove(h, key) {
         return Caml_array.set(h.data, i, next);
       } else {
         prec.next = next;
-        return ;
+        return;
       }
     }
     _param = next;
@@ -313,7 +313,7 @@ function find(h, key) {
 function find_opt(h, key) {
   var match = Caml_array.get(h.data, key_index(h, key));
   if (typeof match !== "object") {
-    return ;
+    return;
   }
   var k1 = match.key;
   var d1 = match.data;
@@ -322,7 +322,7 @@ function find_opt(h, key) {
     return Caml_option.some(d1);
   }
   if (typeof next1 !== "object") {
-    return ;
+    return;
   }
   var k2 = next1.key;
   var d2 = next1.data;
@@ -331,7 +331,7 @@ function find_opt(h, key) {
     return Caml_option.some(d2);
   }
   if (typeof next2 !== "object") {
-    return ;
+    return;
   }
   var k3 = next2.key;
   var d3 = next2.data;
@@ -343,7 +343,7 @@ function find_opt(h, key) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var k = param.key;
       var data = param.data;
@@ -412,7 +412,7 @@ function replace(h, key, data) {
     if (h.size > (h.data.length << 1)) {
       return resize(key_index, h);
     } else {
-      return ;
+      return;
     }
   }
   
@@ -440,7 +440,7 @@ function iter(f, h) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var key = param.key;
       var data = param.data;
@@ -462,7 +462,7 @@ function iter(f, h) {
     if (!old_trav) {
       return flip_ongoing_traversal(h);
     } else {
-      return ;
+      return;
     }
   }
   catch (exn){
@@ -483,7 +483,7 @@ function filter_map_inplace_bucket(f, h, i, _prec, _param) {
         return Caml_array.set(h.data, i, "Empty");
       } else {
         prec.next = "Empty";
-        return ;
+        return;
       }
     }
     var key = param.key;
@@ -517,7 +517,7 @@ function filter_map_inplace(f, h) {
     for(var i = 0 ,i_finish = d.length; i < i_finish; ++i){
       filter_map_inplace_bucket(f, h, i, "Empty", Caml_array.get(h.data, i));
     }
-    return ;
+    return;
   }
   catch (exn){
     if (old_trav) {
@@ -626,7 +626,7 @@ function MakeSeeded(H) {
       var param = _param;
       var prec = _prec;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var k = param.key;
       var next = param.next;
@@ -636,7 +636,7 @@ function MakeSeeded(H) {
           return Caml_array.set(h.data, i, next);
         } else {
           prec.next = next;
-          return ;
+          return;
         }
       }
       _param = next;
@@ -705,7 +705,7 @@ function MakeSeeded(H) {
   var find_opt = function (h, key) {
     var match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      return ;
+      return;
     }
     var k1 = match.key;
     var d1 = match.data;
@@ -714,7 +714,7 @@ function MakeSeeded(H) {
       return Caml_option.some(d1);
     }
     if (typeof next1 !== "object") {
-      return ;
+      return;
     }
     var k2 = next1.key;
     var d2 = next1.data;
@@ -723,7 +723,7 @@ function MakeSeeded(H) {
       return Caml_option.some(d2);
     }
     if (typeof next2 !== "object") {
-      return ;
+      return;
     }
     var k3 = next2.key;
     var d3 = next2.data;
@@ -735,7 +735,7 @@ function MakeSeeded(H) {
       while(true) {
         var param = _param;
         if (typeof param !== "object") {
-          return ;
+          return;
         }
         var k = param.key;
         var data = param.data;
@@ -801,7 +801,7 @@ function MakeSeeded(H) {
       if (h.size > (h.data.length << 1)) {
         return resize(key_index, h);
       } else {
-        return ;
+        return;
       }
     }
     
@@ -870,7 +870,7 @@ function Make(H) {
       var param = _param;
       var prec = _prec;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var k = param.key;
       var next = param.next;
@@ -880,7 +880,7 @@ function Make(H) {
           return Caml_array.set(h.data, i, next);
         } else {
           prec.next = next;
-          return ;
+          return;
         }
       }
       _param = next;
@@ -949,7 +949,7 @@ function Make(H) {
   var find_opt = function (h, key) {
     var match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      return ;
+      return;
     }
     var k1 = match.key;
     var d1 = match.data;
@@ -958,7 +958,7 @@ function Make(H) {
       return Caml_option.some(d1);
     }
     if (typeof next1 !== "object") {
-      return ;
+      return;
     }
     var k2 = next1.key;
     var d2 = next1.data;
@@ -967,7 +967,7 @@ function Make(H) {
       return Caml_option.some(d2);
     }
     if (typeof next2 !== "object") {
-      return ;
+      return;
     }
     var k3 = next2.key;
     var d3 = next2.data;
@@ -979,7 +979,7 @@ function Make(H) {
       while(true) {
         var param = _param;
         if (typeof param !== "object") {
-          return ;
+          return;
         }
         var k = param.key;
         var data = param.data;
@@ -1045,7 +1045,7 @@ function Make(H) {
       if (h.size > (h.data.length << 1)) {
         return resize(key_index, h);
       } else {
-        return ;
+        return;
       }
     }
     
diff --git a/lib/es6/int32.js b/lib/es6/int32.js
index 6fc29286d8..b185287101 100644
--- a/lib/es6/int32.js
+++ b/lib/es6/int32.js
@@ -35,7 +35,7 @@ function of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/es6/int64.js b/lib/es6/int64.js
index b8d88a904f..5f2a0c4945 100644
--- a/lib/es6/int64.js
+++ b/lib/es6/int64.js
@@ -28,7 +28,7 @@ function of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/es6/js_list.js b/lib/es6/js_list.js
index 9342eedd4f..a312106fc9 100644
--- a/lib/es6/js_list.js
+++ b/lib/es6/js_list.js
@@ -45,7 +45,7 @@ function tl(x) {
 
 function nth(l, n) {
   if (n < 0) {
-    return ;
+    return;
   }
   var _l = l;
   var _n = n;
@@ -53,7 +53,7 @@ function nth(l, n) {
     var n$1 = _n;
     var l$1 = _l;
     if (!l$1) {
-      return ;
+      return;
     }
     if (n$1 === 0) {
       return Caml_option.some(l$1.hd);
@@ -112,7 +112,7 @@ function iter(f, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     f(x.hd);
     _x = x.tl;
@@ -127,7 +127,7 @@ function iteri(f, l) {
     var x = _x;
     var i = _i;
     if (!x) {
-      return ;
+      return;
     }
     f(i, x.hd);
     _x = x.tl;
diff --git a/lib/es6/js_mapperRt.js b/lib/es6/js_mapperRt.js
index 6b1bbe936f..5f95a14bc9 100644
--- a/lib/es6/js_mapperRt.js
+++ b/lib/es6/js_mapperRt.js
@@ -16,7 +16,7 @@ function fromInt(len, xs, $$enum) {
   while(true) {
     var i = _i;
     if (i === len) {
-      return ;
+      return;
     }
     var k = xs[i];
     if (k === $$enum) {
diff --git a/lib/es6/js_option.js b/lib/es6/js_option.js
index bde68e4168..e00f882693 100644
--- a/lib/es6/js_option.js
+++ b/lib/es6/js_option.js
@@ -65,7 +65,7 @@ function getWithDefault(a, x) {
 
 function filter(f, x) {
   if (x === undefined) {
-    return ;
+    return;
   }
   var x$1 = Caml_option.valFromOption(x);
   if (f(x$1)) {
@@ -80,7 +80,7 @@ function firstSome(a, b) {
   } else if (b !== undefined) {
     return b;
   } else {
-    return ;
+    return;
   }
 }
 
diff --git a/lib/es6/lexing.js b/lib/es6/lexing.js
index 72ae353974..b7726205d4 100644
--- a/lib/es6/lexing.js
+++ b/lib/es6/lexing.js
@@ -128,7 +128,7 @@ function sub_lexeme(lexbuf, i1, i2) {
 
 function sub_lexeme_opt(lexbuf, i1, i2) {
   if (i1 < 0) {
-    return ;
+    return;
   }
   var len = i2 - i1 | 0;
   return Bytes.sub_string(lexbuf.lex_buffer, i1, len);
diff --git a/lib/es6/list.js b/lib/es6/list.js
index 06f4a3b81d..2bd31b8ed8 100644
--- a/lib/es6/list.js
+++ b/lib/es6/list.js
@@ -92,7 +92,7 @@ function nth_opt(l, n) {
     var n$1 = _n;
     var l$1 = _l;
     if (!l$1) {
-      return ;
+      return;
     }
     if (n$1 === 0) {
       return Caml_option.some(l$1.hd);
@@ -221,7 +221,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     Curry._1(f, param.hd);
     _param = param.tl;
@@ -236,7 +236,7 @@ function iteri(f, l) {
     var param = _param;
     var i = _i;
     if (!param) {
-      return ;
+      return;
     }
     Curry._2(f, i, param.hd);
     _param = param.tl;
@@ -344,7 +344,7 @@ function iter2(f, _l1, _l2) {
           };
     }
     if (!l2) {
-      return ;
+      return;
     }
     throw {
           RE_EXN_ID: "Invalid_argument",
@@ -542,7 +542,7 @@ function assoc_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (Caml_obj.equal(match[0], x)) {
@@ -575,7 +575,7 @@ function assq_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (match[0] === x) {
@@ -668,7 +668,7 @@ function find_opt(p, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var x = param.hd;
     if (Curry._1(p, x)) {
diff --git a/lib/es6/listLabels.js b/lib/es6/listLabels.js
index 983f669643..93f0c82ca2 100644
--- a/lib/es6/listLabels.js
+++ b/lib/es6/listLabels.js
@@ -92,7 +92,7 @@ function nth_opt(l, n) {
     var n$1 = _n;
     var l$1 = _l;
     if (!l$1) {
-      return ;
+      return;
     }
     if (n$1 === 0) {
       return Caml_option.some(l$1.hd);
@@ -221,7 +221,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     Curry._1(f, param.hd);
     _param = param.tl;
@@ -236,7 +236,7 @@ function iteri(f, l) {
     var param = _param;
     var i = _i;
     if (!param) {
-      return ;
+      return;
     }
     Curry._2(f, i, param.hd);
     _param = param.tl;
@@ -344,7 +344,7 @@ function iter2(f, _l1, _l2) {
           };
     }
     if (!l2) {
-      return ;
+      return;
     }
     throw {
           RE_EXN_ID: "Invalid_argument",
@@ -542,7 +542,7 @@ function assoc_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (Caml_obj.equal(match[0], x)) {
@@ -575,7 +575,7 @@ function assq_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (match[0] === x) {
@@ -668,7 +668,7 @@ function find_opt(p, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var x = param.hd;
     if (Curry._1(p, x)) {
diff --git a/lib/es6/map.js b/lib/es6/map.js
index e01de6e75a..42330cccae 100644
--- a/lib/es6/map.js
+++ b/lib/es6/map.js
@@ -207,7 +207,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -282,7 +282,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -318,7 +318,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var c = Curry._2(funarg.compare, x, param.v);
       if (c === 0) {
@@ -366,7 +366,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -403,7 +403,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -527,7 +527,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._2(f, param.v, param.d);
diff --git a/lib/es6/mapLabels.js b/lib/es6/mapLabels.js
index 2b36009a20..89f62d8d68 100644
--- a/lib/es6/mapLabels.js
+++ b/lib/es6/mapLabels.js
@@ -229,7 +229,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -304,7 +304,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -318,7 +318,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var c = Curry._2(Ord.compare, x, param.v);
       if (c === 0) {
@@ -366,7 +366,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -403,7 +403,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -527,7 +527,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._2(f, param.v, param.d);
diff --git a/lib/es6/moreLabels.js b/lib/es6/moreLabels.js
index fd887c3e3b..ea81848e68 100644
--- a/lib/es6/moreLabels.js
+++ b/lib/es6/moreLabels.js
@@ -259,7 +259,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -334,7 +334,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -348,7 +348,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var c = Curry._2(funarg.compare, x, param.v);
           if (c === 0) {
@@ -396,7 +396,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var l = param.l;
           if (typeof l !== "object") {
@@ -433,7 +433,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var r = param.r;
           if (typeof r !== "object") {
@@ -557,7 +557,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           iter(f, param.l);
           Curry._2(f, param.v, param.d);
@@ -1150,7 +1150,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var l = param.l;
           if (typeof l !== "object") {
@@ -1181,7 +1181,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var r = param.r;
           if (typeof r !== "object") {
@@ -1465,7 +1465,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           iter(f, param.l);
           Curry._1(f, param.v);
@@ -1662,7 +1662,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -1727,7 +1727,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -1741,7 +1741,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           var c = Curry._2(funarg.compare, x, v);
diff --git a/lib/es6/pervasives.js b/lib/es6/pervasives.js
index 33d8ca19eb..f6daf9d40a 100644
--- a/lib/es6/pervasives.js
+++ b/lib/es6/pervasives.js
@@ -102,7 +102,7 @@ function bool_of_string_opt(param) {
     case "true" :
         return true;
     default:
-      return ;
+      return;
   }
 }
 
@@ -113,7 +113,7 @@ function int_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -154,7 +154,7 @@ function float_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/es6/pervasivesU.js b/lib/es6/pervasivesU.js
index 7af95656b4..88c672d8cf 100644
--- a/lib/es6/pervasivesU.js
+++ b/lib/es6/pervasivesU.js
@@ -101,7 +101,7 @@ function bool_of_string_opt(param) {
     case "true" :
         return true;
     default:
-      return ;
+      return;
   }
 }
 
@@ -112,7 +112,7 @@ function int_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -153,7 +153,7 @@ function float_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/es6/queue.js b/lib/es6/queue.js
index 910448c503..a6e8b02800 100644
--- a/lib/es6/queue.js
+++ b/lib/es6/queue.js
@@ -30,7 +30,7 @@ function add(x, q) {
     q.length = 1;
     q.first = cell;
     q.last = cell;
-    return ;
+    return;
   }
   q.length = q.length + 1 | 0;
   last.next = cell;
@@ -112,7 +112,7 @@ function iter(f, q) {
   while(true) {
     var cell = _cell;
     if (typeof cell !== "object") {
-      return ;
+      return;
     }
     var next = cell.next;
     Curry._1(f, cell.content);
@@ -140,7 +140,7 @@ function fold(f, accu, q) {
 
 function transfer(q1, q2) {
   if (q1.length <= 0) {
-    return ;
+    return;
   }
   var last = q2.last;
   if (typeof last !== "object") {
diff --git a/lib/es6/set.js b/lib/es6/set.js
index e6a6576575..99645863e9 100644
--- a/lib/es6/set.js
+++ b/lib/es6/set.js
@@ -177,7 +177,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -208,7 +208,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -488,7 +488,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._1(f, param.v);
@@ -667,7 +667,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -730,7 +730,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -760,7 +760,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       var c = Curry._2(funarg.compare, x, v);
diff --git a/lib/es6/setLabels.js b/lib/es6/setLabels.js
index 1a4de23910..a89a70adf8 100644
--- a/lib/es6/setLabels.js
+++ b/lib/es6/setLabels.js
@@ -177,7 +177,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -208,7 +208,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -492,7 +492,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._1(f, param.v);
@@ -689,7 +689,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -754,7 +754,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -768,7 +768,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       var c = Curry._2(Ord.compare, x, v);
diff --git a/lib/es6/sort.js b/lib/es6/sort.js
index 580dd5dd92..ae182a584c 100644
--- a/lib/es6/sort.js
+++ b/lib/es6/sort.js
@@ -98,7 +98,7 @@ function array(cmp, arr) {
       var hi = _hi;
       var lo = _lo;
       if ((hi - lo | 0) < 6) {
-        return ;
+        return;
       }
       var mid = ((lo + hi | 0) >>> 1);
       if (Curry._2(cmp, arr[mid], arr[lo])) {
diff --git a/lib/es6/stream.js b/lib/es6/stream.js
index 52e9953326..7760711967 100644
--- a/lib/es6/stream.js
+++ b/lib/es6/stream.js
@@ -103,7 +103,7 @@ function peek_data(s) {
   while(true) {
     var f = s.data;
     if (typeof f !== "object") {
-      return ;
+      return;
     }
     switch (f.TAG) {
       case "Scons" :
@@ -111,7 +111,7 @@ function peek_data(s) {
       case "Sapp" :
           var d = get_data(s.count, s.data);
           if (typeof d !== "object") {
-            return ;
+            return;
           }
           if (d.TAG === "Scons") {
             s.data = d;
@@ -158,14 +158,14 @@ function junk_data(s) {
         case "Scons" :
             s.count = s.count + 1 | 0;
             s.data = g._1;
-            return ;
+            return;
         case "Sgen" :
             var g$1 = g._0;
             var match = g$1.curr;
             if (match !== undefined) {
               s.count = s.count + 1 | 0;
               g$1.curr = undefined;
-              return ;
+              return;
             }
             break;
         default:
@@ -174,7 +174,7 @@ function junk_data(s) {
     }
     var match$1 = peek_data(s);
     if (match$1 === undefined) {
-      return ;
+      return;
     }
     continue ;
   };
@@ -246,7 +246,7 @@ function next(s) {
 function empty(s) {
   var match = peek(s);
   if (match === undefined) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: Failure,
@@ -259,7 +259,7 @@ function iter(f, strm) {
   while(true) {
     var a = peek(strm);
     if (a === undefined) {
-      return ;
+      return;
     }
     junk(strm);
     Curry._1(f, Caml_option.valFromOption(a));
@@ -418,7 +418,7 @@ function slazy(f) {
 function dump_data(f, param) {
   if (typeof param !== "object") {
     console.log("Sempty");
-    return ;
+    return;
   }
   switch (param.TAG) {
     case "Scons" :
@@ -427,20 +427,20 @@ function dump_data(f, param) {
         console.log(", ");
         dump_data(f, param._1);
         console.log(")");
-        return ;
+        return;
     case "Sapp" :
         console.log("Sapp (");
         dump_data(f, param._0);
         console.log(", ");
         dump_data(f, param._1);
         console.log(")");
-        return ;
+        return;
     case "Slazy" :
         console.log("Slazy");
-        return ;
+        return;
     case "Sgen" :
         console.log("Sgen");
-        return ;
+        return;
     
   }
 }
diff --git a/lib/es6/string.js b/lib/es6/string.js
index 25af7e5643..a340ef7690 100644
--- a/lib/es6/string.js
+++ b/lib/es6/string.js
@@ -112,7 +112,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -186,7 +186,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
diff --git a/lib/es6/stringLabels.js b/lib/es6/stringLabels.js
index 83feed9747..67fe3a00c0 100644
--- a/lib/es6/stringLabels.js
+++ b/lib/es6/stringLabels.js
@@ -114,7 +114,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -188,7 +188,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
diff --git a/lib/js/arg.js b/lib/js/arg.js
index caae76bace..d4ed16fddb 100644
--- a/lib/js/arg.js
+++ b/lib/js/arg.js
@@ -124,7 +124,7 @@ function usage_b(buf, speclist, errmsg) {
   List.iter((function (param) {
           var doc = param[2];
           if (doc.length === 0) {
-            return ;
+            return;
           }
           var spec = param[1];
           var key = param[0];
@@ -157,7 +157,7 @@ function bool_of_string_opt(x) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Invalid_argument") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -170,7 +170,7 @@ function int_of_string_opt(x) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -183,7 +183,7 @@ function float_of_string_opt(x) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -279,7 +279,7 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
         var no_arg = (function(s,follow){
         return function no_arg(param) {
           if (follow === undefined) {
-            return ;
+            return;
           }
           throw {
                 RE_EXN_ID: Stop,
@@ -314,10 +314,10 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
         var consume_arg = (function(follow){
         return function consume_arg(param) {
           if (follow !== undefined) {
-            return ;
+            return;
           } else {
             current.contents = current.contents + 1 | 0;
-            return ;
+            return;
           }
         }
         }(follow));
@@ -347,11 +347,11 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
             case "Set" :
                 no_arg();
                 f._0.contents = true;
-                return ;
+                return;
             case "Clear" :
                 no_arg();
                 f._0.contents = false;
-                return ;
+                return;
             case "String" :
                 var arg$1 = get_arg();
                 Curry._1(f._0, arg$1);
@@ -456,7 +456,7 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
                   Curry._1(f$1, Caml_array.get(argv.contents, current.contents + 1 | 0));
                   consume_arg();
                 };
-                return ;
+                return;
             case "Expand" :
                 if (!allow_expand) {
                   throw {
@@ -480,7 +480,7 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
                         }
                       }
                     });
-                return ;
+                return;
             
           }
         }
diff --git a/lib/js/array.js b/lib/js/array.js
index 016c51f289..a500e2f415 100644
--- a/lib/js/array.js
+++ b/lib/js/array.js
@@ -395,7 +395,7 @@ function sort(cmp, a) {
     trickleup(bubble(i$1, 0), e);
   }
   if (l <= 1) {
-    return ;
+    return;
   }
   var e$1 = Caml_array.get(a, 1);
   Caml_array.set(a, 1, Caml_array.get(a, 0));
diff --git a/lib/js/arrayLabels.js b/lib/js/arrayLabels.js
index cb25b43970..eddbbc8ae2 100644
--- a/lib/js/arrayLabels.js
+++ b/lib/js/arrayLabels.js
@@ -395,7 +395,7 @@ function sort(cmp, a) {
     trickleup(bubble(i$1, 0), e);
   }
   if (l <= 1) {
-    return ;
+    return;
   }
   var e$1 = Caml_array.get(a, 1);
   Caml_array.set(a, 1, Caml_array.get(a, 0));
diff --git a/lib/js/belt_Array.js b/lib/js/belt_Array.js
index c0cf35d5a3..3573416e00 100644
--- a/lib/js/belt_Array.js
+++ b/lib/js/belt_Array.js
@@ -241,14 +241,14 @@ function sliceToEnd(a, offset) {
 
 function fill(a, offset, len, v) {
   if (len <= 0) {
-    return ;
+    return;
   }
   var lena = a.length;
   var ofs = offset < 0 ? Caml.int_max(lena + offset | 0, 0) : offset;
   var hasLen = lena - ofs | 0;
   var fillLength = hasLen < len ? hasLen : len;
   if (fillLength <= 0) {
-    return ;
+    return;
   }
   for(var i = ofs ,i_finish = ofs + fillLength | 0; i < i_finish; ++i){
     a[i] = v;
@@ -260,7 +260,7 @@ function blitUnsafe(a1, srcofs1, a2, srcofs2, blitLength) {
     for(var j = 0; j < blitLength; ++j){
       a2[j + srcofs2 | 0] = a1[j + srcofs1 | 0];
     }
-    return ;
+    return;
   }
   for(var j$1 = blitLength - 1 | 0; j$1 >= 0; --j$1){
     a2[j$1 + srcofs2 | 0] = a1[j$1 + srcofs1 | 0];
@@ -277,7 +277,7 @@ function blit(a1, ofs1, a2, ofs2, len) {
     for(var j = 0; j < blitLength; ++j){
       a2[j + srcofs2 | 0] = a1[j + srcofs1 | 0];
     }
-    return ;
+    return;
   }
   for(var j$1 = blitLength - 1 | 0; j$1 >= 0; --j$1){
     a2[j$1 + srcofs2 | 0] = a1[j$1 + srcofs1 | 0];
diff --git a/lib/js/belt_Float.js b/lib/js/belt_Float.js
index 82772975ff..fa12f4ce89 100644
--- a/lib/js/belt_Float.js
+++ b/lib/js/belt_Float.js
@@ -4,7 +4,7 @@
 function fromString(i) {
   var i$1 = parseFloat(i);
   if (isNaN(i$1)) {
-    return ;
+    return;
   } else {
     return i$1;
   }
diff --git a/lib/js/belt_HashMap.js b/lib/js/belt_HashMap.js
index 29524fb71e..5ccd56ea40 100644
--- a/lib/js/belt_HashMap.js
+++ b/lib/js/belt_HashMap.js
@@ -12,7 +12,7 @@ function copyBucketReHash(hash, h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = hash(old_bucket.key) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -71,7 +71,7 @@ function set0(h, key, value, eq, hash) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -86,7 +86,7 @@ function set0(h, key, value, eq, hash) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
@@ -100,13 +100,13 @@ function remove(h, key) {
   var i = h.hash(key) & (h_buckets.length - 1 | 0);
   var bucket = h_buckets[i];
   if (bucket === undefined) {
-    return ;
+    return;
   }
   var eq = h.eq;
   if (eq(bucket.key, key)) {
     h_buckets[i] = bucket.next;
     h.size = h.size - 1 | 0;
-    return ;
+    return;
   } else {
     var _prec = bucket;
     var _bucket = bucket.next;
@@ -114,13 +114,13 @@ function remove(h, key) {
       var bucket$1 = _bucket;
       var prec = _prec;
       if (bucket$1 === undefined) {
-        return ;
+        return;
       }
       var cell_next = bucket$1.next;
       if (eq(bucket$1.key, key)) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       _bucket = cell_next;
       _prec = bucket$1;
@@ -134,7 +134,7 @@ function get(h, key) {
   var nid = h.hash(key) & (h_buckets.length - 1 | 0);
   var cell1 = h_buckets[nid];
   if (cell1 === undefined) {
-    return ;
+    return;
   }
   var eq = h.eq;
   if (eq(key, cell1.key)) {
@@ -142,7 +142,7 @@ function get(h, key) {
   }
   var cell2 = cell1.next;
   if (cell2 === undefined) {
-    return ;
+    return;
   }
   if (eq(key, cell2.key)) {
     return Caml_option.some(cell2.value);
@@ -156,7 +156,7 @@ function get(h, key) {
       while(true) {
         var buckets = _buckets;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         if (eq(key, buckets.key)) {
           return Caml_option.some(buckets.value);
diff --git a/lib/js/belt_HashMapInt.js b/lib/js/belt_HashMapInt.js
index eb1f958ff8..81c242a846 100644
--- a/lib/js/belt_HashMapInt.js
+++ b/lib/js/belt_HashMapInt.js
@@ -9,7 +9,7 @@ function copyBucketReHash(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -68,7 +68,7 @@ function set(h, key, value) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -83,7 +83,7 @@ function set(h, key, value) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
@@ -96,7 +96,7 @@ function remove(h, key) {
     if (bucket.key === key) {
       h_buckets[i] = bucket.next;
       h.size = h.size - 1 | 0;
-      return ;
+      return;
     } else {
       var _prec = bucket;
       var _buckets = bucket.next;
@@ -104,13 +104,13 @@ function remove(h, key) {
         var buckets = _buckets;
         var prec = _prec;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         var cell_next = buckets.next;
         if (buckets.key === key) {
           prec.next = cell_next;
           h.size = h.size - 1 | 0;
-          return ;
+          return;
         }
         _buckets = cell_next;
         _prec = buckets;
@@ -126,14 +126,14 @@ function get(h, key) {
   var nid = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, key)) & (h_buckets.length - 1 | 0);
   var cell1 = h_buckets[nid];
   if (cell1 === undefined) {
-    return ;
+    return;
   }
   if (key === cell1.key) {
     return Caml_option.some(cell1.value);
   }
   var cell2 = cell1.next;
   if (cell2 === undefined) {
-    return ;
+    return;
   }
   if (key === cell2.key) {
     return Caml_option.some(cell2.value);
@@ -147,7 +147,7 @@ function get(h, key) {
       while(true) {
         var buckets = _buckets;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         if (key === buckets.key) {
           return Caml_option.some(buckets.value);
diff --git a/lib/js/belt_HashMapString.js b/lib/js/belt_HashMapString.js
index 3b89c0ef57..3a62f15254 100644
--- a/lib/js/belt_HashMapString.js
+++ b/lib/js/belt_HashMapString.js
@@ -9,7 +9,7 @@ function copyBucketReHash(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -68,7 +68,7 @@ function set(h, key, value) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -83,7 +83,7 @@ function set(h, key, value) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
@@ -96,7 +96,7 @@ function remove(h, key) {
     if (bucket.key === key) {
       h_buckets[i] = bucket.next;
       h.size = h.size - 1 | 0;
-      return ;
+      return;
     } else {
       var _prec = bucket;
       var _buckets = bucket.next;
@@ -104,13 +104,13 @@ function remove(h, key) {
         var buckets = _buckets;
         var prec = _prec;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         var cell_next = buckets.next;
         if (buckets.key === key) {
           prec.next = cell_next;
           h.size = h.size - 1 | 0;
-          return ;
+          return;
         }
         _buckets = cell_next;
         _prec = buckets;
@@ -126,14 +126,14 @@ function get(h, key) {
   var nid = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, key)) & (h_buckets.length - 1 | 0);
   var cell1 = h_buckets[nid];
   if (cell1 === undefined) {
-    return ;
+    return;
   }
   if (key === cell1.key) {
     return Caml_option.some(cell1.value);
   }
   var cell2 = cell1.next;
   if (cell2 === undefined) {
-    return ;
+    return;
   }
   if (key === cell2.key) {
     return Caml_option.some(cell2.value);
@@ -147,7 +147,7 @@ function get(h, key) {
       while(true) {
         var buckets = _buckets;
         if (buckets === undefined) {
-          return ;
+          return;
         }
         if (key === buckets.key) {
           return Caml_option.some(buckets.value);
diff --git a/lib/js/belt_HashSet.js b/lib/js/belt_HashSet.js
index e654bee9d5..bc1a72d5fc 100644
--- a/lib/js/belt_HashSet.js
+++ b/lib/js/belt_HashSet.js
@@ -7,7 +7,7 @@ function copyBucket(hash, h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = hash(old_bucket.key) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -28,13 +28,13 @@ function remove(h, key) {
   var i = h.hash(key) & (h_buckets.length - 1 | 0);
   var l = h_buckets[i];
   if (l === undefined) {
-    return ;
+    return;
   }
   var next_cell = l.next;
   if (eq(l.key, key)) {
     h.size = h.size - 1 | 0;
     h_buckets[i] = next_cell;
-    return ;
+    return;
   } else if (next_cell !== undefined) {
     var _prec = l;
     var _cell = next_cell;
@@ -45,17 +45,17 @@ function remove(h, key) {
       if (eq(cell.key, key)) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       if (cell_next === undefined) {
-        return ;
+        return;
       }
       _cell = cell_next;
       _prec = cell;
       continue ;
     };
   } else {
-    return ;
+    return;
   }
 }
 
@@ -63,7 +63,7 @@ function addBucket(h, key, _cell, eq) {
   while(true) {
     var cell = _cell;
     if (eq(cell.key, key)) {
-      return ;
+      return;
     }
     var n = cell.next;
     if (n !== undefined) {
@@ -75,7 +75,7 @@ function addBucket(h, key, _cell, eq) {
       key: key,
       next: undefined
     };
-    return ;
+    return;
   };
 }
 
@@ -98,7 +98,7 @@ function add0(h, key, hash, eq) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -113,7 +113,7 @@ function add0(h, key, hash, eq) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_HashSetInt.js b/lib/js/belt_HashSetInt.js
index 60e3881469..0014b66db0 100644
--- a/lib/js/belt_HashSetInt.js
+++ b/lib/js/belt_HashSetInt.js
@@ -8,7 +8,7 @@ function copyBucket(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -28,13 +28,13 @@ function remove(h, key) {
   var i = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_int(0, key)) & (h_buckets.length - 1 | 0);
   var l = h_buckets[i];
   if (l === undefined) {
-    return ;
+    return;
   }
   var next_cell = l.next;
   if (l.key === key) {
     h.size = h.size - 1 | 0;
     h_buckets[i] = next_cell;
-    return ;
+    return;
   } else if (next_cell !== undefined) {
     var _prec = l;
     var _cell = next_cell;
@@ -45,17 +45,17 @@ function remove(h, key) {
       if (cell.key === key) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       if (cell_next === undefined) {
-        return ;
+        return;
       }
       _cell = cell_next;
       _prec = cell;
       continue ;
     };
   } else {
-    return ;
+    return;
   }
 }
 
@@ -63,7 +63,7 @@ function addBucket(h, key, _cell) {
   while(true) {
     var cell = _cell;
     if (cell.key === key) {
-      return ;
+      return;
     }
     var n = cell.next;
     if (n !== undefined) {
@@ -75,7 +75,7 @@ function addBucket(h, key, _cell) {
       key: key,
       next: undefined
     };
-    return ;
+    return;
   };
 }
 
@@ -98,7 +98,7 @@ function add(h, key) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -113,7 +113,7 @@ function add(h, key) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_HashSetString.js b/lib/js/belt_HashSetString.js
index 6d7fbad7f9..4b0cd0f75d 100644
--- a/lib/js/belt_HashSetString.js
+++ b/lib/js/belt_HashSetString.js
@@ -8,7 +8,7 @@ function copyBucket(h_buckets, ndata_tail, _old_bucket) {
   while(true) {
     var old_bucket = _old_bucket;
     if (old_bucket === undefined) {
-      return ;
+      return;
     }
     var nidx = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, old_bucket.key)) & (h_buckets.length - 1 | 0);
     var tail = ndata_tail[nidx];
@@ -28,13 +28,13 @@ function remove(h, key) {
   var i = Caml_hash_primitive.hash_final_mix(Caml_hash_primitive.hash_mix_string(0, key)) & (h_buckets.length - 1 | 0);
   var l = h_buckets[i];
   if (l === undefined) {
-    return ;
+    return;
   }
   var next_cell = l.next;
   if (l.key === key) {
     h.size = h.size - 1 | 0;
     h_buckets[i] = next_cell;
-    return ;
+    return;
   } else if (next_cell !== undefined) {
     var _prec = l;
     var _cell = next_cell;
@@ -45,17 +45,17 @@ function remove(h, key) {
       if (cell.key === key) {
         prec.next = cell_next;
         h.size = h.size - 1 | 0;
-        return ;
+        return;
       }
       if (cell_next === undefined) {
-        return ;
+        return;
       }
       _cell = cell_next;
       _prec = cell;
       continue ;
     };
   } else {
-    return ;
+    return;
   }
 }
 
@@ -63,7 +63,7 @@ function addBucket(h, key, _cell) {
   while(true) {
     var cell = _cell;
     if (cell.key === key) {
-      return ;
+      return;
     }
     var n = cell.next;
     if (n !== undefined) {
@@ -75,7 +75,7 @@ function addBucket(h, key, _cell) {
       key: key,
       next: undefined
     };
-    return ;
+    return;
   };
 }
 
@@ -98,7 +98,7 @@ function add(h, key) {
     var osize = odata.length;
     var nsize = (osize << 1);
     if (nsize < osize) {
-      return ;
+      return;
     }
     var h_buckets$1 = new Array(nsize);
     var ndata_tail = new Array(nsize);
@@ -113,7 +113,7 @@ function add(h, key) {
       }
       
     }
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_Int.js b/lib/js/belt_Int.js
index 4268ada690..63db421977 100644
--- a/lib/js/belt_Int.js
+++ b/lib/js/belt_Int.js
@@ -4,7 +4,7 @@
 function fromString(i) {
   var i$1 = parseInt(i, 10);
   if (isNaN(i$1)) {
-    return ;
+    return;
   } else {
     return i$1;
   }
diff --git a/lib/js/belt_List.js b/lib/js/belt_List.js
index a0baa8ed6f..59968e901d 100644
--- a/lib/js/belt_List.js
+++ b/lib/js/belt_List.js
@@ -48,7 +48,7 @@ function add(xs, x) {
 
 function get(x, n) {
   if (n < 0) {
-    return ;
+    return;
   } else {
     var _x = x;
     var _n = n;
@@ -56,7 +56,7 @@ function get(x, n) {
       var n$1 = _n;
       var x$1 = _x;
       if (!x$1) {
-        return ;
+        return;
       }
       if (n$1 === 0) {
         return Caml_option.some(x$1.hd);
@@ -101,7 +101,7 @@ function partitionAux(p, _cell, _precX, _precY) {
     var precX = _precX;
     var cell = _cell;
     if (!cell) {
-      return ;
+      return;
     }
     var t = cell.tl;
     var h = cell.hd;
@@ -128,7 +128,7 @@ function splitAux(_cell, _precX, _precY) {
     var precX = _precX;
     var cell = _cell;
     if (!cell) {
-      return ;
+      return;
     }
     var match = cell.hd;
     var nextA = {
@@ -171,7 +171,7 @@ function copyAuxWitFilter(f, _cellX, _prec) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var t = cellX.tl;
     var h = cellX.hd;
@@ -196,7 +196,7 @@ function copyAuxWithFilterIndex(f, _cellX, _prec, _i) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var t = cellX.tl;
     var h = cellX.hd;
@@ -222,7 +222,7 @@ function copyAuxWitFilterMap(f, _cellX, _prec) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var t = cellX.tl;
     var h = f(cellX.hd);
@@ -300,7 +300,7 @@ function copyAuxWithMap(_cellX, _prec, f) {
     var prec = _prec;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     var next = {
       hd: f(cellX.hd),
@@ -319,10 +319,10 @@ function zipAux(_cellX, _cellY, _prec) {
     var cellY = _cellY;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     if (!cellY) {
-      return ;
+      return;
     }
     var next = {
       hd: [
@@ -345,10 +345,10 @@ function copyAuxWithMap2(f, _cellX, _cellY, _prec) {
     var cellY = _cellY;
     var cellX = _cellX;
     if (!cellX) {
-      return ;
+      return;
     }
     if (!cellY) {
-      return ;
+      return;
     }
     var next = {
       hd: f(cellX.hd, cellY.hd),
@@ -368,7 +368,7 @@ function copyAuxWithMapI(f, _i, _cellX, _prec) {
     var cellX = _cellX;
     var i = _i;
     if (!cellX) {
-      return ;
+      return;
     }
     var next = {
       hd: f(i, cellX.hd),
@@ -414,7 +414,7 @@ function splitAtAux(_n, _cell, _prec) {
       return cell;
     }
     if (!cell) {
-      return ;
+      return;
     }
     var cell$1 = {
       hd: cell.hd,
@@ -430,13 +430,13 @@ function splitAtAux(_n, _cell, _prec) {
 
 function take(lst, n) {
   if (n < 0) {
-    return ;
+    return;
   }
   if (n === 0) {
     return /* [] */0;
   }
   if (!lst) {
-    return ;
+    return;
   }
   var cell = {
     hd: lst.hd,
@@ -451,7 +451,7 @@ function take(lst, n) {
 
 function drop(lst, n) {
   if (n < 0) {
-    return ;
+    return;
   } else {
     var _l = lst;
     var _n = n;
@@ -462,7 +462,7 @@ function drop(lst, n) {
         return l;
       }
       if (!l) {
-        return ;
+        return;
       }
       _n = n$1 - 1 | 0;
       _l = l.tl;
@@ -473,7 +473,7 @@ function drop(lst, n) {
 
 function splitAt(lst, n) {
   if (n < 0) {
-    return ;
+    return;
   }
   if (n === 0) {
     return [
@@ -482,7 +482,7 @@ function splitAt(lst, n) {
           ];
   }
   if (!lst) {
-    return ;
+    return;
   }
   var cell = {
     hd: lst.hd,
@@ -629,7 +629,7 @@ function fillAux(arr, _i, _x) {
     var x = _x;
     var i = _i;
     if (!x) {
-      return ;
+      return;
     }
     arr[i] = x.hd;
     _x = x.tl;
@@ -699,7 +699,7 @@ function flattenAux(_prec, _xs) {
       continue ;
     }
     prec.tl = /* [] */0;
-    return ;
+    return;
   };
 }
 
@@ -765,7 +765,7 @@ function forEachU(_xs, f) {
   while(true) {
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     f(xs.hd);
     _xs = xs.tl;
@@ -784,7 +784,7 @@ function forEachWithIndexU(l, f) {
     var i = _i;
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     f(i, xs.hd);
     _i = i + 1 | 0;
@@ -890,10 +890,10 @@ function forEach2U(_l1, _l2, f) {
     var l2 = _l2;
     var l1 = _l1;
     if (!l1) {
-      return ;
+      return;
     }
     if (!l2) {
-      return ;
+      return;
     }
     f(l1.hd, l2.hd);
     _l2 = l2.tl;
@@ -1128,7 +1128,7 @@ function getAssocU(_xs, x, eq) {
   while(true) {
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     var match = xs.hd;
     if (eq(match[0], x)) {
@@ -1243,7 +1243,7 @@ function getByU(_xs, p) {
   while(true) {
     var xs = _xs;
     if (!xs) {
-      return ;
+      return;
     }
     var x = xs.hd;
     if (p(x)) {
diff --git a/lib/js/belt_MapDict.js b/lib/js/belt_MapDict.js
index ea4e1a614b..d04b1413f1 100644
--- a/lib/js/belt_MapDict.js
+++ b/lib/js/belt_MapDict.js
@@ -205,7 +205,7 @@ function mergeU(s1, s2, f, cmp) {
                     return f(k, undefined, Caml_option.some(v));
                   }));
     } else {
-      return ;
+      return;
     }
   }
   if (s2 === undefined) {
diff --git a/lib/js/belt_MutableMap.js b/lib/js/belt_MutableMap.js
index fd49cf330d..86770aceb9 100644
--- a/lib/js/belt_MutableMap.js
+++ b/lib/js/belt_MutableMap.js
@@ -44,12 +44,12 @@ function removeMutateAux(nt, x, cmp) {
 function remove(d, k) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = removeMutateAux(oldRoot, k, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -64,7 +64,7 @@ function removeArrayMutateAux(_t, xs, _i, len, cmp) {
     var ele = xs[i];
     var u = removeMutateAux(t, ele, cmp);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -75,13 +75,13 @@ function removeArrayMutateAux(_t, xs, _i, len, cmp) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   var newRoot = removeArrayMutateAux(oldRoot, xs, 0, len, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -131,7 +131,7 @@ function updateU(t, x, f) {
   var newRoot = updateDone(oldRoot, x, f, t.cmp);
   if (newRoot !== oldRoot) {
     t.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -315,7 +315,7 @@ function set(m, e, v) {
   var newRoot = Belt_internalAVLtree.updateMutate(oldRoot, e, v, m.cmp);
   if (newRoot !== oldRoot) {
     m.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -334,7 +334,7 @@ function mergeMany(d, xs) {
   var newRoot = mergeManyAux(oldRoot, xs, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_MutableMapInt.js b/lib/js/belt_MutableMapInt.js
index b1f05685ee..1bc41b8211 100644
--- a/lib/js/belt_MutableMapInt.js
+++ b/lib/js/belt_MutableMapInt.js
@@ -57,7 +57,7 @@ function set(m, k, v) {
   var v$1 = Belt_internalMapInt.addMutate(old_data, k, v);
   if (v$1 !== old_data) {
     m.data = v$1;
-    return ;
+    return;
   }
   
 }
@@ -179,12 +179,12 @@ function removeMutateAux(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = removeMutateAux(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -234,7 +234,7 @@ function updateU(t, x, f) {
   var newRoot = updateDone(oldRoot, x, f);
   if (newRoot !== oldRoot) {
     t.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -253,7 +253,7 @@ function removeArrayMutateAux(_t, xs, _i, len) {
     var ele = xs[i];
     var u = removeMutateAux(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -264,13 +264,13 @@ function removeArrayMutateAux(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   var newRoot = removeArrayMutateAux(oldRoot, xs, 0, len);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_MutableMapString.js b/lib/js/belt_MutableMapString.js
index 372ad59574..54ac042f63 100644
--- a/lib/js/belt_MutableMapString.js
+++ b/lib/js/belt_MutableMapString.js
@@ -57,7 +57,7 @@ function set(m, k, v) {
   var v$1 = Belt_internalMapString.addMutate(old_data, k, v);
   if (v$1 !== old_data) {
     m.data = v$1;
-    return ;
+    return;
   }
   
 }
@@ -179,12 +179,12 @@ function removeMutateAux(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = removeMutateAux(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -234,7 +234,7 @@ function updateU(t, x, f) {
   var newRoot = updateDone(oldRoot, x, f);
   if (newRoot !== oldRoot) {
     t.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -253,7 +253,7 @@ function removeArrayMutateAux(_t, xs, _i, len) {
     var ele = xs[i];
     var u = removeMutateAux(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -264,13 +264,13 @@ function removeArrayMutateAux(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   var newRoot = removeArrayMutateAux(oldRoot, xs, 0, len);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_MutableQueue.js b/lib/js/belt_MutableQueue.js
index a5b8e2fcf8..32faa0361b 100644
--- a/lib/js/belt_MutableQueue.js
+++ b/lib/js/belt_MutableQueue.js
@@ -64,7 +64,7 @@ function peekExn(q) {
 function pop(q) {
   var x = q.first;
   if (x === undefined) {
-    return ;
+    return;
   }
   var next = x.next;
   if (next === undefined) {
@@ -99,7 +99,7 @@ function popExn(q) {
 function popUndefined(q) {
   var x = q.first;
   if (x === undefined) {
-    return ;
+    return;
   }
   var next = x.next;
   if (next === undefined) {
@@ -191,7 +191,7 @@ function forEachU(q, f) {
   while(true) {
     var cell = _cell;
     if (cell === undefined) {
-      return ;
+      return;
     }
     f(cell.content);
     _cell = cell.next;
@@ -225,7 +225,7 @@ function reduce(q, accu, f) {
 
 function transfer(q1, q2) {
   if (q1.length <= 0) {
-    return ;
+    return;
   }
   var l = q2.last;
   if (l !== undefined) {
@@ -246,7 +246,7 @@ function fillAux(_i, arr, _cell) {
     var cell = _cell;
     var i = _i;
     if (cell === undefined) {
-      return ;
+      return;
     }
     arr[i] = cell.content;
     _cell = cell.next;
diff --git a/lib/js/belt_MutableSet.js b/lib/js/belt_MutableSet.js
index ef52cc621f..9b9d1403cf 100644
--- a/lib/js/belt_MutableSet.js
+++ b/lib/js/belt_MutableSet.js
@@ -42,12 +42,12 @@ function remove0(nt, x, cmp) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = remove0(oldRoot, v, d.cmp);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -62,7 +62,7 @@ function removeMany0(_t, xs, _i, len, cmp) {
     var ele = xs[i];
     var u = remove0(t, ele, cmp);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -73,7 +73,7 @@ function removeMany0(_t, xs, _i, len, cmp) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   d.data = removeMany0(oldRoot, xs, 0, len, d.cmp);
@@ -168,7 +168,7 @@ function add(m, e) {
   var newRoot = Belt_internalAVLset.addMutate(m.cmp, oldRoot, e);
   if (newRoot !== oldRoot) {
     m.data = newRoot;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_MutableSetInt.js b/lib/js/belt_MutableSetInt.js
index 893ec9dfc0..6ff5418169 100644
--- a/lib/js/belt_MutableSetInt.js
+++ b/lib/js/belt_MutableSetInt.js
@@ -42,12 +42,12 @@ function remove0(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = remove0(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -62,7 +62,7 @@ function removeMany0(_t, xs, _i, len) {
     var ele = xs[i];
     var u = remove0(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -73,7 +73,7 @@ function removeMany0(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   d.data = removeMany0(oldRoot, xs, 0, len);
@@ -166,7 +166,7 @@ function add(d, k) {
   var v = Belt_internalSetInt.addMutate(oldRoot, k);
   if (v !== oldRoot) {
     d.data = v;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_MutableSetString.js b/lib/js/belt_MutableSetString.js
index 6da37904ad..3ab85c7080 100644
--- a/lib/js/belt_MutableSetString.js
+++ b/lib/js/belt_MutableSetString.js
@@ -42,12 +42,12 @@ function remove0(nt, x) {
 function remove(d, v) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var newRoot = remove0(oldRoot, v);
   if (newRoot !== oldRoot) {
     d.data = newRoot;
-    return ;
+    return;
   }
   
 }
@@ -62,7 +62,7 @@ function removeMany0(_t, xs, _i, len) {
     var ele = xs[i];
     var u = remove0(t, ele);
     if (u === undefined) {
-      return ;
+      return;
     }
     _i = i + 1 | 0;
     _t = u;
@@ -73,7 +73,7 @@ function removeMany0(_t, xs, _i, len) {
 function removeMany(d, xs) {
   var oldRoot = d.data;
   if (oldRoot === undefined) {
-    return ;
+    return;
   }
   var len = xs.length;
   d.data = removeMany0(oldRoot, xs, 0, len);
@@ -166,7 +166,7 @@ function add(d, k) {
   var v = Belt_internalSetString.addMutate(oldRoot, k);
   if (v !== oldRoot) {
     d.data = v;
-    return ;
+    return;
   }
   
 }
diff --git a/lib/js/belt_MutableStack.js b/lib/js/belt_MutableStack.js
index c82ccef3e3..bcce699022 100644
--- a/lib/js/belt_MutableStack.js
+++ b/lib/js/belt_MutableStack.js
@@ -90,7 +90,7 @@ function forEachU(s, f) {
   while(true) {
     var s$1 = _s;
     if (s$1 === undefined) {
-      return ;
+      return;
     }
     f(s$1.head);
     _s = s$1.tail;
@@ -106,7 +106,7 @@ function dynamicPopIterU(s, f) {
   while(true) {
     var match = s.root;
     if (match === undefined) {
-      return ;
+      return;
     }
     s.root = match.tail;
     f(match.head);
diff --git a/lib/js/belt_SetDict.js b/lib/js/belt_SetDict.js
index 410c492659..b0f1f56e96 100644
--- a/lib/js/belt_SetDict.js
+++ b/lib/js/belt_SetDict.js
@@ -212,10 +212,10 @@ function union(s1, s2, cmp) {
 
 function intersect(s1, s2, cmp) {
   if (s1 === undefined) {
-    return ;
+    return;
   }
   if (s2 === undefined) {
-    return ;
+    return;
   }
   var v1 = s1.v;
   var l1 = s1.l;
diff --git a/lib/js/belt_SetInt.js b/lib/js/belt_SetInt.js
index c99b75349c..faa5c9cd82 100644
--- a/lib/js/belt_SetInt.js
+++ b/lib/js/belt_SetInt.js
@@ -209,10 +209,10 @@ function union(s1, s2) {
 
 function intersect(s1, s2) {
   if (s1 === undefined) {
-    return ;
+    return;
   }
   if (s2 === undefined) {
-    return ;
+    return;
   }
   var v1 = s1.v;
   var l1 = s1.l;
diff --git a/lib/js/belt_SetString.js b/lib/js/belt_SetString.js
index 26d6975022..fe845b3fee 100644
--- a/lib/js/belt_SetString.js
+++ b/lib/js/belt_SetString.js
@@ -209,10 +209,10 @@ function union(s1, s2) {
 
 function intersect(s1, s2) {
   if (s1 === undefined) {
-    return ;
+    return;
   }
   if (s2 === undefined) {
-    return ;
+    return;
   }
   var v1 = s1.v;
   var l1 = s1.l;
diff --git a/lib/js/belt_internalAVLset.js b/lib/js/belt_internalAVLset.js
index 8140346f0c..f9c4f17aec 100644
--- a/lib/js/belt_internalAVLset.js
+++ b/lib/js/belt_internalAVLset.js
@@ -168,7 +168,7 @@ function forEachU(_n, f) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     forEachU(n.l, f);
     f(n.v);
@@ -360,7 +360,7 @@ function checkInvariantInternal(_v) {
   while(true) {
     var v = _v;
     if (v === undefined) {
-      return ;
+      return;
     }
     var l = v.l;
     var r = v.r;
@@ -424,7 +424,7 @@ function fillArrayWithPartition(_n, cursor, arr, p) {
       cursor.backward = c$1 - 1 | 0;
     }
     if (r === undefined) {
-      return ;
+      return;
     }
     _n = r;
     continue ;
@@ -462,7 +462,7 @@ function toArray(n) {
 function fromSortedArrayRevAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         return singleton(arr[off]);
     case 2 :
@@ -496,7 +496,7 @@ function fromSortedArrayRevAux(arr, off, len) {
 function fromSortedArrayAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         return singleton(arr[off]);
     case 2 :
@@ -533,7 +533,7 @@ function fromSortedArrayUnsafe(arr) {
 
 function keepSharedU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var v = n.v;
   var l = n.l;
@@ -558,7 +558,7 @@ function keepShared(n, p) {
 
 function keepCopyU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var size = lengthNode(n);
   var v = new Array(size);
@@ -692,7 +692,7 @@ function get(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     var c = cmp(x, v);
@@ -708,7 +708,7 @@ function getUndefined(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     var c = cmp(x, v);
@@ -856,7 +856,7 @@ function addMutate(cmp, t, x) {
 function fromArray(xs, cmp) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (x, y) {
           return cmp(x, y) < 0;
diff --git a/lib/js/belt_internalAVLtree.js b/lib/js/belt_internalAVLtree.js
index f9f85077b4..13ac5b321e 100644
--- a/lib/js/belt_internalAVLtree.js
+++ b/lib/js/belt_internalAVLtree.js
@@ -247,7 +247,7 @@ function stackAllLeft(_v, _s) {
 
 function findFirstByU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var left = findFirstByU(n.l, p);
   if (left !== undefined) {
@@ -277,7 +277,7 @@ function forEachU(_n, f) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     forEachU(n.l, f);
     f(n.k, n.v);
@@ -292,7 +292,7 @@ function forEach(n, f) {
 
 function mapU(n, f) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var newLeft = mapU(n.l, f);
   var newD = f(n.v);
@@ -312,7 +312,7 @@ function map(n, f) {
 
 function mapWithKeyU(n, f) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var key = n.k;
   var newLeft = mapWithKeyU(n.l, f);
@@ -463,7 +463,7 @@ function concatOrJoin(t1, v, d, t2) {
 
 function keepSharedU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var v = n.k;
   var d = n.v;
@@ -483,7 +483,7 @@ function keepShared(n, p) {
 
 function keepMapU(n, p) {
   if (n === undefined) {
-    return ;
+    return;
   }
   var v = n.k;
   var d = n.v;
@@ -581,7 +581,7 @@ function checkInvariantInternal(_v) {
   while(true) {
     var v = _v;
     if (v === undefined) {
-      return ;
+      return;
     }
     var l = v.l;
     var r = v.r;
@@ -695,7 +695,7 @@ function valuesToArray(n) {
 function fromSortedArrayRevAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         var match = arr[off];
         return singleton(match[0], match[1]);
@@ -737,7 +737,7 @@ function fromSortedArrayRevAux(arr, off, len) {
 function fromSortedArrayAux(arr, off, len) {
   switch (len) {
     case 0 :
-        return ;
+        return;
     case 1 :
         var match = arr[off];
         return singleton(match[0], match[1]);
@@ -857,7 +857,7 @@ function get(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     var c = cmp(x, v);
@@ -873,7 +873,7 @@ function getUndefined(_n, x, cmp) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     var c = cmp(x, v);
@@ -1046,7 +1046,7 @@ function updateMutate(t, x, data, cmp) {
 function fromArray(xs, cmp) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (param, param$1) {
           return cmp(param[0], param$1[0]) < 0;
diff --git a/lib/js/belt_internalBuckets.js b/lib/js/belt_internalBuckets.js
index eabd14bcbc..40312067bc 100644
--- a/lib/js/belt_internalBuckets.js
+++ b/lib/js/belt_internalBuckets.js
@@ -22,7 +22,7 @@ function copyAuxCont(_c, _prec) {
     var prec = _prec;
     var c = _c;
     if (c === undefined) {
-      return ;
+      return;
     }
     var ncopy = {
       key: c.key,
@@ -71,7 +71,7 @@ function do_bucket_iter(f, _buckets) {
   while(true) {
     var buckets = _buckets;
     if (buckets === undefined) {
-      return ;
+      return;
     }
     f(buckets.key, buckets.value);
     _buckets = buckets.next;
@@ -163,7 +163,7 @@ function filterMapInplaceBucket(f, h, i, _prec, _cell) {
       cell.value = Caml_option.valFromOption(data);
       if (n === undefined) {
         cell.next = n;
-        return ;
+        return;
       }
       _cell = n;
       _prec = cell;
@@ -176,7 +176,7 @@ function filterMapInplaceBucket(f, h, i, _prec, _cell) {
       } else {
         h.buckets[i] = prec;
       }
-      return ;
+      return;
     }
     _cell = n;
     continue ;
diff --git a/lib/js/belt_internalMapInt.js b/lib/js/belt_internalMapInt.js
index 2887d9e588..263dc515d5 100644
--- a/lib/js/belt_internalMapInt.js
+++ b/lib/js/belt_internalMapInt.js
@@ -26,7 +26,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -41,7 +41,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -198,7 +198,7 @@ function mergeU(s1, s2, f) {
     }
     
   } else if (s2 === undefined) {
-    return ;
+    return;
   }
   var v2 = s2.k;
   var d2 = s2.v;
@@ -313,7 +313,7 @@ function addMutate(t, x, data) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (param, param$1) {
           return param[0] < param$1[0];
diff --git a/lib/js/belt_internalMapString.js b/lib/js/belt_internalMapString.js
index 97b43e8504..a466ab1639 100644
--- a/lib/js/belt_internalMapString.js
+++ b/lib/js/belt_internalMapString.js
@@ -26,7 +26,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -41,7 +41,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.k;
     if (x === v) {
@@ -198,7 +198,7 @@ function mergeU(s1, s2, f) {
     }
     
   } else if (s2 === undefined) {
-    return ;
+    return;
   }
   var v2 = s2.k;
   var d2 = s2.v;
@@ -313,7 +313,7 @@ function addMutate(t, x, data) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArray.strictlySortedLengthU(xs, (function (param, param$1) {
           return param[0] < param$1[0];
diff --git a/lib/js/belt_internalSetBuckets.js b/lib/js/belt_internalSetBuckets.js
index 00b7d16e77..ab07a34819 100644
--- a/lib/js/belt_internalSetBuckets.js
+++ b/lib/js/belt_internalSetBuckets.js
@@ -8,7 +8,7 @@ function copyAuxCont(_c, _prec) {
     var prec = _prec;
     var c = _c;
     if (c === undefined) {
-      return ;
+      return;
     }
     var ncopy = {
       key: c.key,
@@ -68,7 +68,7 @@ function doBucketIter(f, _buckets) {
   while(true) {
     var buckets = _buckets;
     if (buckets === undefined) {
-      return ;
+      return;
     }
     f(buckets.key);
     _buckets = buckets.next;
diff --git a/lib/js/belt_internalSetInt.js b/lib/js/belt_internalSetInt.js
index 32d5a313de..e8855a2421 100644
--- a/lib/js/belt_internalSetInt.js
+++ b/lib/js/belt_internalSetInt.js
@@ -104,7 +104,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -119,7 +119,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -169,7 +169,7 @@ function addMutate(t, x) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArrayInt.strictlySortedLength(xs);
   var result;
diff --git a/lib/js/belt_internalSetString.js b/lib/js/belt_internalSetString.js
index e29bec2363..3a47cb8cff 100644
--- a/lib/js/belt_internalSetString.js
+++ b/lib/js/belt_internalSetString.js
@@ -104,7 +104,7 @@ function get(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -119,7 +119,7 @@ function getUndefined(_n, x) {
   while(true) {
     var n = _n;
     if (n === undefined) {
-      return ;
+      return;
     }
     var v = n.v;
     if (x === v) {
@@ -169,7 +169,7 @@ function addMutate(t, x) {
 function fromArray(xs) {
   var len = xs.length;
   if (len === 0) {
-    return ;
+    return;
   }
   var next = Belt_SortArrayString.strictlySortedLength(xs);
   var result;
diff --git a/lib/js/buffer.js b/lib/js/buffer.js
index 9b0720b7fe..2806ddab75 100644
--- a/lib/js/buffer.js
+++ b/lib/js/buffer.js
@@ -117,7 +117,7 @@ function add_utf_8_uchar(b, u) {
     b.buffer[pos] = 192 | (u$1 >>> 6);
     b.buffer[pos + 1 | 0] = 128 | u$1 & 63;
     b.position = pos + 2 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 65535) {
     var pos$1 = b.position;
@@ -128,7 +128,7 @@ function add_utf_8_uchar(b, u) {
     b.buffer[pos$1 + 1 | 0] = 128 | (u$1 >>> 6) & 63;
     b.buffer[pos$1 + 2 | 0] = 128 | u$1 & 63;
     b.position = pos$1 + 3 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 1114111) {
     var pos$2 = b.position;
@@ -140,7 +140,7 @@ function add_utf_8_uchar(b, u) {
     b.buffer[pos$2 + 2 | 0] = 128 | (u$1 >>> 6) & 63;
     b.buffer[pos$2 + 3 | 0] = 128 | u$1 & 63;
     b.position = pos$2 + 4 | 0;
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -174,7 +174,7 @@ function add_utf_16be_uchar(b, u) {
     b.buffer[pos] = (u$1 >>> 8);
     b.buffer[pos + 1 | 0] = u$1 & 255;
     b.position = pos + 2 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 1114111) {
     var u$p = u$1 - 65536 | 0;
@@ -189,7 +189,7 @@ function add_utf_16be_uchar(b, u) {
     b.buffer[pos$1 + 2 | 0] = (lo >>> 8);
     b.buffer[pos$1 + 3 | 0] = lo & 255;
     b.position = pos$1 + 4 | 0;
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -223,7 +223,7 @@ function add_utf_16le_uchar(b, u) {
     b.buffer[pos] = u$1 & 255;
     b.buffer[pos + 1 | 0] = (u$1 >>> 8);
     b.position = pos + 2 | 0;
-    return ;
+    return;
   }
   if (u$1 <= 1114111) {
     var u$p = u$1 - 65536 | 0;
@@ -238,7 +238,7 @@ function add_utf_16le_uchar(b, u) {
     b.buffer[pos$1 + 2 | 0] = lo & 255;
     b.buffer[pos$1 + 3 | 0] = (lo >>> 8);
     b.position = pos$1 + 4 | 0;
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
@@ -404,7 +404,7 @@ function add_substitute(b, f, s) {
       if (previous === /* '\\' */92) {
         return add_char(b, previous);
       } else {
-        return ;
+        return;
       }
     }
     var current = Caml_string.get(s, i);
diff --git a/lib/js/bytes.js b/lib/js/bytes.js
index 38a3229018..5229566a5b 100644
--- a/lib/js/bytes.js
+++ b/lib/js/bytes.js
@@ -8,7 +8,7 @@ var Caml_js_exceptions = require("./caml_js_exceptions.js");
 
 function unsafe_fill(s, i, l, c) {
   if (l <= 0) {
-    return ;
+    return;
   }
   for(var k = i ,k_finish = l + i | 0; k < k_finish; ++k){
     s[k] = c;
@@ -17,7 +17,7 @@ function unsafe_fill(s, i, l, c) {
 
 function unsafe_blit(s1, i1, s2, i2, len) {
   if (len <= 0) {
-    return ;
+    return;
   }
   if (s1 === s2) {
     if (i1 < i2) {
@@ -27,10 +27,10 @@ function unsafe_blit(s1, i1, s2, i2, len) {
       for(var j = range; j >= 0; --j){
         s1[i2 + j | 0] = s1[i1 + j | 0];
       }
-      return ;
+      return;
     }
     if (i1 <= i2) {
-      return ;
+      return;
     }
     var range_a$1 = (s1.length - i1 | 0) - 1 | 0;
     var range_b$1 = len - 1 | 0;
@@ -38,14 +38,14 @@ function unsafe_blit(s1, i1, s2, i2, len) {
     for(var k = 0; k <= range$1; ++k){
       s1[i2 + k | 0] = s1[i1 + k | 0];
     }
-    return ;
+    return;
   }
   var off1 = s1.length - i1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[i2 + i | 0] = s1[i1 + i | 0];
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[i2 + i$1 | 0] = s1[i1 + i$1 | 0];
@@ -207,14 +207,14 @@ function blit_string(s1, ofs1, s2, ofs2, len) {
         };
   }
   if (len <= 0) {
-    return ;
+    return;
   }
   var off1 = s1.length - ofs1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[ofs2 + i | 0] = s1.codePointAt(ofs1 + i | 0);
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[ofs2 + i$1 | 0] = s1.codePointAt(ofs1 + i$1 | 0);
@@ -506,7 +506,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
@@ -580,7 +580,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
diff --git a/lib/js/bytesLabels.js b/lib/js/bytesLabels.js
index 38a3229018..5229566a5b 100644
--- a/lib/js/bytesLabels.js
+++ b/lib/js/bytesLabels.js
@@ -8,7 +8,7 @@ var Caml_js_exceptions = require("./caml_js_exceptions.js");
 
 function unsafe_fill(s, i, l, c) {
   if (l <= 0) {
-    return ;
+    return;
   }
   for(var k = i ,k_finish = l + i | 0; k < k_finish; ++k){
     s[k] = c;
@@ -17,7 +17,7 @@ function unsafe_fill(s, i, l, c) {
 
 function unsafe_blit(s1, i1, s2, i2, len) {
   if (len <= 0) {
-    return ;
+    return;
   }
   if (s1 === s2) {
     if (i1 < i2) {
@@ -27,10 +27,10 @@ function unsafe_blit(s1, i1, s2, i2, len) {
       for(var j = range; j >= 0; --j){
         s1[i2 + j | 0] = s1[i1 + j | 0];
       }
-      return ;
+      return;
     }
     if (i1 <= i2) {
-      return ;
+      return;
     }
     var range_a$1 = (s1.length - i1 | 0) - 1 | 0;
     var range_b$1 = len - 1 | 0;
@@ -38,14 +38,14 @@ function unsafe_blit(s1, i1, s2, i2, len) {
     for(var k = 0; k <= range$1; ++k){
       s1[i2 + k | 0] = s1[i1 + k | 0];
     }
-    return ;
+    return;
   }
   var off1 = s1.length - i1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[i2 + i | 0] = s1[i1 + i | 0];
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[i2 + i$1 | 0] = s1[i1 + i$1 | 0];
@@ -207,14 +207,14 @@ function blit_string(s1, ofs1, s2, ofs2, len) {
         };
   }
   if (len <= 0) {
-    return ;
+    return;
   }
   var off1 = s1.length - ofs1 | 0;
   if (len <= off1) {
     for(var i = 0; i < len; ++i){
       s2[ofs2 + i | 0] = s1.codePointAt(ofs1 + i | 0);
     }
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < off1; ++i$1){
     s2[ofs2 + i$1 | 0] = s1.codePointAt(ofs1 + i$1 | 0);
@@ -506,7 +506,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
@@ -580,7 +580,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s[i] === c) {
       return i;
diff --git a/lib/js/caml_array.js b/lib/js/caml_array.js
index b82047a0a1..7fd284b4d2 100644
--- a/lib/js/caml_array.js
+++ b/lib/js/caml_array.js
@@ -31,7 +31,7 @@ function fill(arr, _i, _l) {
     var l = _l;
     var i = _i;
     if (!l) {
-      return ;
+      return;
     }
     var x = l.hd;
     var l$1 = x.length;
@@ -98,7 +98,7 @@ function blit(a1, i1, a2, i2, len) {
     for(var j = 0; j < len; ++j){
       a2[j + i2 | 0] = a1[j + i1 | 0];
     }
-    return ;
+    return;
   }
   for(var j$1 = len - 1 | 0; j$1 >= 0; --j$1){
     a2[j$1 + i2 | 0] = a1[j$1 + i1 | 0];
diff --git a/lib/js/caml_module.js b/lib/js/caml_module.js
index 1cd2221f78..da3066a0b9 100644
--- a/lib/js/caml_module.js
+++ b/lib/js/caml_module.js
@@ -16,7 +16,7 @@ function init_mod(loc, shape) {
         case "Function" :
         case "Lazy" :
             struct_[idx] = undef_module;
-            return ;
+            return;
         case "Class" :
             struct_[idx] = [
               undef_module,
@@ -24,7 +24,7 @@ function init_mod(loc, shape) {
               undef_module,
               0
             ];
-            return ;
+            return;
         
       }
     } else {
@@ -37,10 +37,10 @@ function init_mod(loc, shape) {
           var match = comps[i];
           loop(match[0], v, match[1]);
         }
-        return ;
+        return;
       }
       struct_[idx] = shape._0;
-      return ;
+      return;
     }
   };
   var res = {};
@@ -55,7 +55,7 @@ function update_mod(shape, o, n) {
       switch (shape) {
         case "Function" :
             parent[i] = n;
-            return ;
+            return;
         case "Lazy" :
         case "Class" :
             return Caml_obj.update_dummy(o, n);
@@ -63,7 +63,7 @@ function update_mod(shape, o, n) {
       }
     } else {
       if (shape.TAG !== "Module") {
-        return ;
+        return;
       }
       var comps = shape._0;
       for(var i$1 = 0 ,i_finish = comps.length; i$1 < i_finish; ++i$1){
@@ -71,7 +71,7 @@ function update_mod(shape, o, n) {
         var name = match[1];
         aux(match[0], o[name], n[name], o, name);
       }
-      return ;
+      return;
     }
   };
   if (typeof shape !== "object") {
@@ -92,7 +92,7 @@ function update_mod(shape, o, n) {
       var name = match[1];
       aux(match[0], o[name], n[name], o, name);
     }
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: "Assert_failure",
diff --git a/lib/js/caml_obj.js b/lib/js/caml_obj.js
index c429ee8578..2cb6e9eb67 100644
--- a/lib/js/caml_obj.js
+++ b/lib/js/caml_obj.js
@@ -215,14 +215,14 @@ function aux_obj_compare(a, b) {
     var min_key = param[2];
     var b = param[1];
     if (!(!Object.prototype.hasOwnProperty.call(b, key) || compare(param[0][key], b[key]) > 0)) {
-      return ;
+      return;
     }
     var mk = min_key.contents;
     if (mk !== undefined && key >= mk) {
-      return ;
+      return;
     } else {
       min_key.contents = key;
-      return ;
+      return;
     }
   };
   var partial_arg = [
@@ -317,14 +317,14 @@ function equal(a, b) {
       var do_key_a = function (key) {
         if (!Object.prototype.hasOwnProperty.call(b, key)) {
           result.contents = false;
-          return ;
+          return;
         }
         
       };
       var do_key_b = function (key) {
         if (!Object.prototype.hasOwnProperty.call(a, key) || !equal(b[key], a[key])) {
           result.contents = false;
-          return ;
+          return;
         }
         
       };
diff --git a/lib/js/caml_option.js b/lib/js/caml_option.js
index 969706a2a9..39266f82c0 100644
--- a/lib/js/caml_option.js
+++ b/lib/js/caml_option.js
@@ -21,7 +21,7 @@ function some(x) {
 
 function nullable_to_opt(x) {
   if (x == null) {
-    return ;
+    return;
   } else {
     return some(x);
   }
@@ -29,7 +29,7 @@ function nullable_to_opt(x) {
 
 function undefined_to_opt(x) {
   if (x === undefined) {
-    return ;
+    return;
   } else {
     return some(x);
   }
@@ -37,7 +37,7 @@ function undefined_to_opt(x) {
 
 function null_to_opt(x) {
   if (x === null) {
-    return ;
+    return;
   } else {
     return some(x);
   }
@@ -49,7 +49,7 @@ function valFromOption(x) {
   }
   var depth = x.BS_PRIVATE_NESTED_SOME_NONE;
   if (depth === 0) {
-    return ;
+    return;
   } else {
     return {
             BS_PRIVATE_NESTED_SOME_NONE: depth - 1 | 0
@@ -59,7 +59,7 @@ function valFromOption(x) {
 
 function option_get(x) {
   if (x === undefined) {
-    return ;
+    return;
   } else {
     return valFromOption(x);
   }
diff --git a/lib/js/genlex.js b/lib/js/genlex.js
index ff3731e9c6..dd03e59817 100644
--- a/lib/js/genlex.js
+++ b/lib/js/genlex.js
@@ -85,7 +85,7 @@ function make_lexer(keywords) {
     while(true) {
       var c = Stream.peek(strm__);
       if (c === undefined) {
-        return ;
+        return;
       }
       var exit = 0;
       if (c < 124) {
@@ -622,7 +622,7 @@ function make_lexer(keywords) {
                     continue ;
                   }
                   Stream.junk(strm__);
-                  return ;
+                  return;
                 }
                 throw {
                       RE_EXN_ID: Stream.Failure,
diff --git a/lib/js/hashtbl.js b/lib/js/hashtbl.js
index ae6d7290d9..dd2c4bae32 100644
--- a/lib/js/hashtbl.js
+++ b/lib/js/hashtbl.js
@@ -84,7 +84,7 @@ function reset(h) {
   } else {
     h.size = 0;
     h.data = Caml_array.make(Pervasives.abs(h.initial_size), "Empty");
-    return ;
+    return;
   }
 }
 
@@ -100,7 +100,7 @@ function copy_bucketlist(param) {
       var param = _param;
       var prec = _prec;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var key = param.key;
       var data = param.data;
@@ -156,7 +156,7 @@ function resize(indexfun, h) {
   var osize = odata.length;
   var nsize = (osize << 1);
   if (nsize < osize) {
-    return ;
+    return;
   }
   var ndata = Caml_array.make(nsize, "Empty");
   var ndata_tail = Caml_array.make(nsize, "Empty");
@@ -166,7 +166,7 @@ function resize(indexfun, h) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var key = param.key;
       var data = param.data;
@@ -193,7 +193,7 @@ function resize(indexfun, h) {
     insert_bucket(Caml_array.get(odata, i));
   }
   if (!inplace) {
-    return ;
+    return;
   }
   for(var i$1 = 0; i$1 < nsize; ++i$1){
     var tail = Caml_array.get(ndata_tail, i$1);
@@ -232,7 +232,7 @@ function remove(h, key) {
     var param = _param;
     var prec = _prec;
     if (typeof param !== "object") {
-      return ;
+      return;
     }
     var k = param.key;
     var next = param.next;
@@ -242,7 +242,7 @@ function remove(h, key) {
         return Caml_array.set(h.data, i, next);
       } else {
         prec.next = next;
-        return ;
+        return;
       }
     }
     _param = next;
@@ -313,7 +313,7 @@ function find(h, key) {
 function find_opt(h, key) {
   var match = Caml_array.get(h.data, key_index(h, key));
   if (typeof match !== "object") {
-    return ;
+    return;
   }
   var k1 = match.key;
   var d1 = match.data;
@@ -322,7 +322,7 @@ function find_opt(h, key) {
     return Caml_option.some(d1);
   }
   if (typeof next1 !== "object") {
-    return ;
+    return;
   }
   var k2 = next1.key;
   var d2 = next1.data;
@@ -331,7 +331,7 @@ function find_opt(h, key) {
     return Caml_option.some(d2);
   }
   if (typeof next2 !== "object") {
-    return ;
+    return;
   }
   var k3 = next2.key;
   var d3 = next2.data;
@@ -343,7 +343,7 @@ function find_opt(h, key) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var k = param.key;
       var data = param.data;
@@ -412,7 +412,7 @@ function replace(h, key, data) {
     if (h.size > (h.data.length << 1)) {
       return resize(key_index, h);
     } else {
-      return ;
+      return;
     }
   }
   
@@ -440,7 +440,7 @@ function iter(f, h) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var key = param.key;
       var data = param.data;
@@ -462,7 +462,7 @@ function iter(f, h) {
     if (!old_trav) {
       return flip_ongoing_traversal(h);
     } else {
-      return ;
+      return;
     }
   }
   catch (exn){
@@ -483,7 +483,7 @@ function filter_map_inplace_bucket(f, h, i, _prec, _param) {
         return Caml_array.set(h.data, i, "Empty");
       } else {
         prec.next = "Empty";
-        return ;
+        return;
       }
     }
     var key = param.key;
@@ -517,7 +517,7 @@ function filter_map_inplace(f, h) {
     for(var i = 0 ,i_finish = d.length; i < i_finish; ++i){
       filter_map_inplace_bucket(f, h, i, "Empty", Caml_array.get(h.data, i));
     }
-    return ;
+    return;
   }
   catch (exn){
     if (old_trav) {
@@ -626,7 +626,7 @@ function MakeSeeded(H) {
       var param = _param;
       var prec = _prec;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var k = param.key;
       var next = param.next;
@@ -636,7 +636,7 @@ function MakeSeeded(H) {
           return Caml_array.set(h.data, i, next);
         } else {
           prec.next = next;
-          return ;
+          return;
         }
       }
       _param = next;
@@ -705,7 +705,7 @@ function MakeSeeded(H) {
   var find_opt = function (h, key) {
     var match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      return ;
+      return;
     }
     var k1 = match.key;
     var d1 = match.data;
@@ -714,7 +714,7 @@ function MakeSeeded(H) {
       return Caml_option.some(d1);
     }
     if (typeof next1 !== "object") {
-      return ;
+      return;
     }
     var k2 = next1.key;
     var d2 = next1.data;
@@ -723,7 +723,7 @@ function MakeSeeded(H) {
       return Caml_option.some(d2);
     }
     if (typeof next2 !== "object") {
-      return ;
+      return;
     }
     var k3 = next2.key;
     var d3 = next2.data;
@@ -735,7 +735,7 @@ function MakeSeeded(H) {
       while(true) {
         var param = _param;
         if (typeof param !== "object") {
-          return ;
+          return;
         }
         var k = param.key;
         var data = param.data;
@@ -801,7 +801,7 @@ function MakeSeeded(H) {
       if (h.size > (h.data.length << 1)) {
         return resize(key_index, h);
       } else {
-        return ;
+        return;
       }
     }
     
@@ -870,7 +870,7 @@ function Make(H) {
       var param = _param;
       var prec = _prec;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var k = param.key;
       var next = param.next;
@@ -880,7 +880,7 @@ function Make(H) {
           return Caml_array.set(h.data, i, next);
         } else {
           prec.next = next;
-          return ;
+          return;
         }
       }
       _param = next;
@@ -949,7 +949,7 @@ function Make(H) {
   var find_opt = function (h, key) {
     var match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      return ;
+      return;
     }
     var k1 = match.key;
     var d1 = match.data;
@@ -958,7 +958,7 @@ function Make(H) {
       return Caml_option.some(d1);
     }
     if (typeof next1 !== "object") {
-      return ;
+      return;
     }
     var k2 = next1.key;
     var d2 = next1.data;
@@ -967,7 +967,7 @@ function Make(H) {
       return Caml_option.some(d2);
     }
     if (typeof next2 !== "object") {
-      return ;
+      return;
     }
     var k3 = next2.key;
     var d3 = next2.data;
@@ -979,7 +979,7 @@ function Make(H) {
       while(true) {
         var param = _param;
         if (typeof param !== "object") {
-          return ;
+          return;
         }
         var k = param.key;
         var data = param.data;
@@ -1045,7 +1045,7 @@ function Make(H) {
       if (h.size > (h.data.length << 1)) {
         return resize(key_index, h);
       } else {
-        return ;
+        return;
       }
     }
     
diff --git a/lib/js/int32.js b/lib/js/int32.js
index 6110414a50..d07dc971d4 100644
--- a/lib/js/int32.js
+++ b/lib/js/int32.js
@@ -35,7 +35,7 @@ function of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/js/int64.js b/lib/js/int64.js
index 7ff4b5bb99..962606c64c 100644
--- a/lib/js/int64.js
+++ b/lib/js/int64.js
@@ -28,7 +28,7 @@ function of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/js/js_list.js b/lib/js/js_list.js
index d9520352da..4a8ba9271c 100644
--- a/lib/js/js_list.js
+++ b/lib/js/js_list.js
@@ -45,7 +45,7 @@ function tl(x) {
 
 function nth(l, n) {
   if (n < 0) {
-    return ;
+    return;
   }
   var _l = l;
   var _n = n;
@@ -53,7 +53,7 @@ function nth(l, n) {
     var n$1 = _n;
     var l$1 = _l;
     if (!l$1) {
-      return ;
+      return;
     }
     if (n$1 === 0) {
       return Caml_option.some(l$1.hd);
@@ -112,7 +112,7 @@ function iter(f, _x) {
   while(true) {
     var x = _x;
     if (!x) {
-      return ;
+      return;
     }
     f(x.hd);
     _x = x.tl;
@@ -127,7 +127,7 @@ function iteri(f, l) {
     var x = _x;
     var i = _i;
     if (!x) {
-      return ;
+      return;
     }
     f(i, x.hd);
     _x = x.tl;
diff --git a/lib/js/js_mapperRt.js b/lib/js/js_mapperRt.js
index 72c0aeb59e..d8a0bfeab0 100644
--- a/lib/js/js_mapperRt.js
+++ b/lib/js/js_mapperRt.js
@@ -16,7 +16,7 @@ function fromInt(len, xs, $$enum) {
   while(true) {
     var i = _i;
     if (i === len) {
-      return ;
+      return;
     }
     var k = xs[i];
     if (k === $$enum) {
diff --git a/lib/js/js_option.js b/lib/js/js_option.js
index 1d61467206..2058dd53ce 100644
--- a/lib/js/js_option.js
+++ b/lib/js/js_option.js
@@ -65,7 +65,7 @@ function getWithDefault(a, x) {
 
 function filter(f, x) {
   if (x === undefined) {
-    return ;
+    return;
   }
   var x$1 = Caml_option.valFromOption(x);
   if (f(x$1)) {
@@ -80,7 +80,7 @@ function firstSome(a, b) {
   } else if (b !== undefined) {
     return b;
   } else {
-    return ;
+    return;
   }
 }
 
diff --git a/lib/js/lexing.js b/lib/js/lexing.js
index a99f07da9c..2b9b7f75b6 100644
--- a/lib/js/lexing.js
+++ b/lib/js/lexing.js
@@ -128,7 +128,7 @@ function sub_lexeme(lexbuf, i1, i2) {
 
 function sub_lexeme_opt(lexbuf, i1, i2) {
   if (i1 < 0) {
-    return ;
+    return;
   }
   var len = i2 - i1 | 0;
   return Bytes.sub_string(lexbuf.lex_buffer, i1, len);
diff --git a/lib/js/list.js b/lib/js/list.js
index 2a4fa3ef68..bc818d61f7 100644
--- a/lib/js/list.js
+++ b/lib/js/list.js
@@ -92,7 +92,7 @@ function nth_opt(l, n) {
     var n$1 = _n;
     var l$1 = _l;
     if (!l$1) {
-      return ;
+      return;
     }
     if (n$1 === 0) {
       return Caml_option.some(l$1.hd);
@@ -221,7 +221,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     Curry._1(f, param.hd);
     _param = param.tl;
@@ -236,7 +236,7 @@ function iteri(f, l) {
     var param = _param;
     var i = _i;
     if (!param) {
-      return ;
+      return;
     }
     Curry._2(f, i, param.hd);
     _param = param.tl;
@@ -344,7 +344,7 @@ function iter2(f, _l1, _l2) {
           };
     }
     if (!l2) {
-      return ;
+      return;
     }
     throw {
           RE_EXN_ID: "Invalid_argument",
@@ -542,7 +542,7 @@ function assoc_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (Caml_obj.equal(match[0], x)) {
@@ -575,7 +575,7 @@ function assq_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (match[0] === x) {
@@ -668,7 +668,7 @@ function find_opt(p, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var x = param.hd;
     if (Curry._1(p, x)) {
diff --git a/lib/js/listLabels.js b/lib/js/listLabels.js
index 0633cbadca..606ee2773a 100644
--- a/lib/js/listLabels.js
+++ b/lib/js/listLabels.js
@@ -92,7 +92,7 @@ function nth_opt(l, n) {
     var n$1 = _n;
     var l$1 = _l;
     if (!l$1) {
-      return ;
+      return;
     }
     if (n$1 === 0) {
       return Caml_option.some(l$1.hd);
@@ -221,7 +221,7 @@ function iter(f, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     Curry._1(f, param.hd);
     _param = param.tl;
@@ -236,7 +236,7 @@ function iteri(f, l) {
     var param = _param;
     var i = _i;
     if (!param) {
-      return ;
+      return;
     }
     Curry._2(f, i, param.hd);
     _param = param.tl;
@@ -344,7 +344,7 @@ function iter2(f, _l1, _l2) {
           };
     }
     if (!l2) {
-      return ;
+      return;
     }
     throw {
           RE_EXN_ID: "Invalid_argument",
@@ -542,7 +542,7 @@ function assoc_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (Caml_obj.equal(match[0], x)) {
@@ -575,7 +575,7 @@ function assq_opt(x, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var match = param.hd;
     if (match[0] === x) {
@@ -668,7 +668,7 @@ function find_opt(p, _param) {
   while(true) {
     var param = _param;
     if (!param) {
-      return ;
+      return;
     }
     var x = param.hd;
     if (Curry._1(p, x)) {
diff --git a/lib/js/map.js b/lib/js/map.js
index da4f3e632a..2b69d73d7b 100644
--- a/lib/js/map.js
+++ b/lib/js/map.js
@@ -207,7 +207,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -282,7 +282,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -318,7 +318,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var c = Curry._2(funarg.compare, x, param.v);
       if (c === 0) {
@@ -366,7 +366,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -403,7 +403,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -527,7 +527,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._2(f, param.v, param.d);
diff --git a/lib/js/mapLabels.js b/lib/js/mapLabels.js
index 5ba10c0afe..dd74689b08 100644
--- a/lib/js/mapLabels.js
+++ b/lib/js/mapLabels.js
@@ -229,7 +229,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -304,7 +304,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -318,7 +318,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var c = Curry._2(Ord.compare, x, param.v);
       if (c === 0) {
@@ -366,7 +366,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -403,7 +403,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -527,7 +527,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._2(f, param.v, param.d);
diff --git a/lib/js/moreLabels.js b/lib/js/moreLabels.js
index c37c95cac2..9ee78021a6 100644
--- a/lib/js/moreLabels.js
+++ b/lib/js/moreLabels.js
@@ -259,7 +259,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -334,7 +334,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -348,7 +348,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var c = Curry._2(funarg.compare, x, param.v);
           if (c === 0) {
@@ -396,7 +396,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var l = param.l;
           if (typeof l !== "object") {
@@ -433,7 +433,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var r = param.r;
           if (typeof r !== "object") {
@@ -557,7 +557,7 @@ var $$Map = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           iter(f, param.l);
           Curry._2(f, param.v, param.d);
@@ -1150,7 +1150,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var l = param.l;
           if (typeof l !== "object") {
@@ -1181,7 +1181,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var r = param.r;
           if (typeof r !== "object") {
@@ -1465,7 +1465,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           iter(f, param.l);
           Curry._1(f, param.v);
@@ -1662,7 +1662,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -1727,7 +1727,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           if (Curry._1(f, v)) {
@@ -1741,7 +1741,7 @@ var $$Set = {
         while(true) {
           var param = _param;
           if (typeof param !== "object") {
-            return ;
+            return;
           }
           var v = param.v;
           var c = Curry._2(funarg.compare, x, v);
diff --git a/lib/js/pervasives.js b/lib/js/pervasives.js
index efcf4fb70d..a1b76422ca 100644
--- a/lib/js/pervasives.js
+++ b/lib/js/pervasives.js
@@ -102,7 +102,7 @@ function bool_of_string_opt(param) {
     case "true" :
         return true;
     default:
-      return ;
+      return;
   }
 }
 
@@ -113,7 +113,7 @@ function int_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -154,7 +154,7 @@ function float_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/js/pervasivesU.js b/lib/js/pervasivesU.js
index 31c6560d8a..2f53bd01cd 100644
--- a/lib/js/pervasivesU.js
+++ b/lib/js/pervasivesU.js
@@ -101,7 +101,7 @@ function bool_of_string_opt(param) {
     case "true" :
         return true;
     default:
-      return ;
+      return;
   }
 }
 
@@ -112,7 +112,7 @@ function int_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
@@ -153,7 +153,7 @@ function float_of_string_opt(s) {
   catch (raw_exn){
     var exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Failure") {
-      return ;
+      return;
     }
     throw exn;
   }
diff --git a/lib/js/queue.js b/lib/js/queue.js
index 3fb8d780f0..a733d2fc82 100644
--- a/lib/js/queue.js
+++ b/lib/js/queue.js
@@ -30,7 +30,7 @@ function add(x, q) {
     q.length = 1;
     q.first = cell;
     q.last = cell;
-    return ;
+    return;
   }
   q.length = q.length + 1 | 0;
   last.next = cell;
@@ -112,7 +112,7 @@ function iter(f, q) {
   while(true) {
     var cell = _cell;
     if (typeof cell !== "object") {
-      return ;
+      return;
     }
     var next = cell.next;
     Curry._1(f, cell.content);
@@ -140,7 +140,7 @@ function fold(f, accu, q) {
 
 function transfer(q1, q2) {
   if (q1.length <= 0) {
-    return ;
+    return;
   }
   var last = q2.last;
   if (typeof last !== "object") {
diff --git a/lib/js/set.js b/lib/js/set.js
index 4f27c4d77f..d442b7f9ae 100644
--- a/lib/js/set.js
+++ b/lib/js/set.js
@@ -177,7 +177,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -208,7 +208,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -488,7 +488,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._1(f, param.v);
@@ -667,7 +667,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -730,7 +730,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -760,7 +760,7 @@ function Make(funarg) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       var c = Curry._2(funarg.compare, x, v);
diff --git a/lib/js/setLabels.js b/lib/js/setLabels.js
index e28f5ec6b9..b59926cf7f 100644
--- a/lib/js/setLabels.js
+++ b/lib/js/setLabels.js
@@ -177,7 +177,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var l = param.l;
       if (typeof l !== "object") {
@@ -208,7 +208,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var r = param.r;
       if (typeof r !== "object") {
@@ -492,7 +492,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       iter(f, param.l);
       Curry._1(f, param.v);
@@ -689,7 +689,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -754,7 +754,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       if (Curry._1(f, v)) {
@@ -768,7 +768,7 @@ function Make(Ord) {
     while(true) {
       var param = _param;
       if (typeof param !== "object") {
-        return ;
+        return;
       }
       var v = param.v;
       var c = Curry._2(Ord.compare, x, v);
diff --git a/lib/js/sort.js b/lib/js/sort.js
index d595df2749..8d15a1a5fe 100644
--- a/lib/js/sort.js
+++ b/lib/js/sort.js
@@ -98,7 +98,7 @@ function array(cmp, arr) {
       var hi = _hi;
       var lo = _lo;
       if ((hi - lo | 0) < 6) {
-        return ;
+        return;
       }
       var mid = ((lo + hi | 0) >>> 1);
       if (Curry._2(cmp, arr[mid], arr[lo])) {
diff --git a/lib/js/stream.js b/lib/js/stream.js
index 324cf40805..eb16b9e0a1 100644
--- a/lib/js/stream.js
+++ b/lib/js/stream.js
@@ -103,7 +103,7 @@ function peek_data(s) {
   while(true) {
     var f = s.data;
     if (typeof f !== "object") {
-      return ;
+      return;
     }
     switch (f.TAG) {
       case "Scons" :
@@ -111,7 +111,7 @@ function peek_data(s) {
       case "Sapp" :
           var d = get_data(s.count, s.data);
           if (typeof d !== "object") {
-            return ;
+            return;
           }
           if (d.TAG === "Scons") {
             s.data = d;
@@ -158,14 +158,14 @@ function junk_data(s) {
         case "Scons" :
             s.count = s.count + 1 | 0;
             s.data = g._1;
-            return ;
+            return;
         case "Sgen" :
             var g$1 = g._0;
             var match = g$1.curr;
             if (match !== undefined) {
               s.count = s.count + 1 | 0;
               g$1.curr = undefined;
-              return ;
+              return;
             }
             break;
         default:
@@ -174,7 +174,7 @@ function junk_data(s) {
     }
     var match$1 = peek_data(s);
     if (match$1 === undefined) {
-      return ;
+      return;
     }
     continue ;
   };
@@ -246,7 +246,7 @@ function next(s) {
 function empty(s) {
   var match = peek(s);
   if (match === undefined) {
-    return ;
+    return;
   }
   throw {
         RE_EXN_ID: Failure,
@@ -259,7 +259,7 @@ function iter(f, strm) {
   while(true) {
     var a = peek(strm);
     if (a === undefined) {
-      return ;
+      return;
     }
     junk(strm);
     Curry._1(f, Caml_option.valFromOption(a));
@@ -418,7 +418,7 @@ function slazy(f) {
 function dump_data(f, param) {
   if (typeof param !== "object") {
     console.log("Sempty");
-    return ;
+    return;
   }
   switch (param.TAG) {
     case "Scons" :
@@ -427,20 +427,20 @@ function dump_data(f, param) {
         console.log(", ");
         dump_data(f, param._1);
         console.log(")");
-        return ;
+        return;
     case "Sapp" :
         console.log("Sapp (");
         dump_data(f, param._0);
         console.log(", ");
         dump_data(f, param._1);
         console.log(")");
-        return ;
+        return;
     case "Slazy" :
         console.log("Slazy");
-        return ;
+        return;
     case "Sgen" :
         console.log("Sgen");
-        return ;
+        return;
     
   }
 }
diff --git a/lib/js/string.js b/lib/js/string.js
index 076b21a317..aeb5ed11d9 100644
--- a/lib/js/string.js
+++ b/lib/js/string.js
@@ -112,7 +112,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -186,7 +186,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
diff --git a/lib/js/stringLabels.js b/lib/js/stringLabels.js
index 22cd4df919..57e01cbf61 100644
--- a/lib/js/stringLabels.js
+++ b/lib/js/stringLabels.js
@@ -114,7 +114,7 @@ function index_rec_opt(s, lim, _i, c) {
   while(true) {
     var i = _i;
     if (i >= lim) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -188,7 +188,7 @@ function rindex_rec_opt(s, _i, c) {
   while(true) {
     var i = _i;
     if (i < 0) {
-      return ;
+      return;
     }
     if (s.codePointAt(i) === c) {
       return i;