[q5438722]

Summary

LRUCache::<T, 0>::new() and default() succeed, but calling insert() panics with an index-out-of-bounds error.

Reproducer

use uluru::LRUCache;

fn main() {
    let mut cache = LRUCache::<u8, 0>::default();
    cache.insert(42); // panics
}

Root Cause

new() checks only the upper capacity bound (N < u16::MAX) and allows N = 0. Since a zero-capacity cache is always full, insert() attempts eviction from an empty array, causing an out-of-bounds panic.

Suggested Fix

// Reject zero capacity in new():

assert!(N > 0, "Capacity must be at least 1");

This makes invalid configurations fail immediately with a clear error instead of panicking on the first insertion.

[emilio]

Sure, I guess.