panic if queue is too big

mino/src/queue.rs

@@ -12,6 +12,10 @@ pub struct Queue<'a, T: Copy> {
 impl<'a, T: Copy> Queue<'a, T> {
     /// Constructs a new queue.
     pub const fn new(mut hold: Option<T>, mut next: &'a [T]) -> Self {
+        if next.len() + 1 > u16::MAX as usize {
+            panic!("too many elements in queue");
+        }
+
         // SIGH. so `hold.is_none()` is not valid in `const fn`, for some obscure reason.
         #[allow(clippy::redundant_pattern_matching)]
         if let None = hold {