Fixed compiler warnings.

src/tasks/day02.rs

@@ -10,7 +10,7 @@ pub fn task1() {
     for line in input.lines() {
         let mut counts = [0u8; 26];
         for c in line.chars() {
-            counts[(c as usize - 'a' as usize)] += 1;
+            counts[c as usize - 'a' as usize] += 1;
         }
         if counts.iter().any(|count| *count == 2) {
             count_two += 1;
@@ -138,7 +138,7 @@ fn check_children_for_match(node: &Node<'_>) -> Option<String> {
             )
         })
         .collect();
-    // go over all suffixes and count their occurences. If # = 2, match!
+    // go over all suffixes and count their occurrences. If # = 2, match!
     let mut suffix_counter: HashMap<&str, usize> = HashMap::new();
     for suffix_set in suffix_candidates.values() {
         for suffix in suffix_set {
@@ -164,7 +164,7 @@ fn add_id_to_tree<'a>(root: &mut Node<'a>, id: &'a str) {
     current.same_prefix.insert(id);
     for (i, c) in id.chars().enumerate() {
         {
-            let mut next = current.outgoing.entry(c).or_insert(Node::default());
+            let next = current.outgoing.entry(c).or_insert(Node::default());
             next.depth = i + 1;
             next.same_prefix.insert(id);
             next.prefix = &id[..=i];

src/tasks/day13.rs

@@ -71,7 +71,7 @@ fn perform_round(map: &[Vec<char>], carts: &mut Vec<Cart>) {
         .collect();
 
     for cart_index in 0..carts.len() {
-        let mut cart = &mut carts[cart_index];
+        let cart = &mut carts[cart_index];
         if !cart.active {
             continue;
         }