Review adjustments

src/lib.rs

@@ -136,14 +136,11 @@ impl<T: Send> Default for ThreadLocal<T> {
 
 impl<T: Send> Drop for ThreadLocal<T> {
     fn drop(&mut self) {
-        let mut bucket_size = 1;
-
         // Free each non-null bucket
-        for bucket in self.buckets.iter_mut() {
+        for (i, bucket) in self.buckets.iter_mut().enumerate() {
             let bucket_ptr = *bucket.get_mut();
 
-            let this_bucket_size = bucket_size;
-            bucket_size <<= 1;
+            let this_bucket_size = 1 << i;
 
             if bucket_ptr.is_null() {
                 break;
@@ -167,11 +164,8 @@ impl<T: Send> ThreadLocal<T> {
         let allocated_buckets = usize::from(POINTER_WIDTH) - (capacity.leading_zeros() as usize);
 
         let mut buckets = [ptr::null_mut(); BUCKETS];
-        let mut bucket_size = 1;
-        for bucket in buckets[..allocated_buckets].iter_mut() {
-            *bucket = allocate_bucket::<T>(bucket_size);
-
-            bucket_size <<= 1;
+        for (i, bucket) in buckets[..allocated_buckets].iter_mut().enumerate() {
+            *bucket = allocate_bucket::<T>(1 << i);
         }
 
         Self {

src/thread_id.rs

@@ -30,11 +30,8 @@ impl ThreadIdManager {
         if let Some(id) = self.free_list.pop() {
             id.0
         } else {
-            // we don't allow 1 before MAX to be returned because our buckets can only contain
-            // up to usize::MAX - 1 elements, but this shouldn't have any impact in practice.
-            if self.free_from >= usize::MAX - 1 {
-                panic!("Ran out of thread IDs");
-            }
+            // `free_from` can't overflow as each thread takes up at least 2 bytes of memory and
+            // thus we can't even have `usize::MAX / 2 + 1` threads.
 
             let id = self.free_from;
             self.free_from += 1;