moonbitlang · bobzhang · Jun 26, 2025 · Jun 26, 2025
diff --git a/array/fixedarray_sort.mbt b/array/fixedarray_sort.mbt
@@ -82,7 +82,7 @@ fn[T : Compare] timsort(arr : FixedArraySlice[T]) -> Unit {
 fn[T : Compare] FixedArraySlice::insertion_sort(
   arr : FixedArraySlice[T]
 ) -> Unit {
-  for i = 1, len = arr.length(); i < len; i = i + 1 {
+  for i in 1..<arr.length() {
     for j = i; j > 0 && arr[j] < arr[j - 1]; j = j - 1 {
       arr.swap(j, j - 1)
     }
@@ -538,7 +538,7 @@ test "stable_sort_complex" {
   let total_len = run_lens.fold(init=0, (acc, x) => acc + x)
   let arr = FixedArray::make(total_len, 0)
   let mut index = 0
-  for i = 0, len = run_lens.length(); i < len; i = i + 1 {
+  for i in 0..<run_lens.length() {
     for j in 0..<run_lens[i] {
       arr[index] = j
       index += 1

diff --git a/builtin/iter_test.mbt b/builtin/iter_test.mbt
@@ -316,7 +316,7 @@ test "concat" {
 test "collect" {
   let arr = ['1', '2', '3', '4', '5']
   let iter = Iter::new(fn(yield_) {
-    for i = 0, len = arr.length(); i < len; i = i + 1 {
+    for i in 0..<arr.length() {
       yield_(arr[i]) |> ignore
     }
     IterContinue

diff --git a/bytes/bytes.mbt b/bytes/bytes.mbt
@@ -214,7 +214,7 @@ pub fn to_array(self : Bytes) -> Array[Byte] {
 /// ```
 pub fn iter(self : Bytes) -> Iter[Byte] {
   Iter::new(fn(yield_) {
-    for i = 0, len = self.length(); i < len; i = i + 1 {
+    for i in 0..<self.length() {
       if yield_(self[i]) == IterEnd {
         break IterEnd
       }
@@ -239,7 +239,7 @@ pub fn iter(self : Bytes) -> Iter[Byte] {
 ///   inspect(keys, content="[0, 1, 2, 3, 4]")
 pub fn iter2(self : Bytes) -> Iter2[Int, Byte] {
   Iter2::new(fn(yield_) {
-    for i = 0, len = self.length(); i < len; i = i + 1 {
+    for i in 0..<self.length() {
       if yield_(i, self[i]) == IterEnd {
         break IterEnd
       }