diff --git a/aoc2020/src/day14.rs b/aoc2020/src/day14.rs
index aaed831..9922034 100644
--- a/aoc2020/src/day14.rs
+++ b/aoc2020/src/day14.rs
@@ -286,7 +286,7 @@ impl Program {
     }
 
     fn memory_sum(&self) -> u64 {
-        self.memory.iter().map(|(_, value)| value).sum()
+        self.memory.values().sum()
     }
 }
 
diff --git a/aoc2020/src/day16.rs b/aoc2020/src/day16.rs
index da0f583..66103ec 100644
--- a/aoc2020/src/day16.rs
+++ b/aoc2020/src/day16.rs
@@ -44,7 +44,6 @@ fn assign_field_positions(
         .iter()
         .map(|(&name, field)| {
             let possibilities = (0..num_values)
-                .into_iter()
                 .filter(|i| tickets.iter().all(|t| t.valid_field(field, *i)))
                 .collect();
 
diff --git a/aoc2020/src/day20.rs b/aoc2020/src/day20.rs
index 5961c59..a671f0e 100644
--- a/aoc2020/src/day20.rs
+++ b/aoc2020/src/day20.rs
@@ -307,8 +307,7 @@ impl Image {
         image_positions.insert((0, 0), tiles[0].clone());
 
         // compute each image position depending on its neighbours
-        while !todo.is_empty() {
-            let pos = todo.pop().unwrap();
+        while let Some(pos) = todo.pop() {
             let tile = &image_positions[&pos];
 
             for (direction, other_tile) in tile.neighbours(tiles) {
@@ -339,9 +338,9 @@ impl Image {
         const IMAGE_TILE_HEIGHT: usize = TILE_HEIGHT - 2;
         const IMAGE_TILE_WIDTH: usize = TILE_WIDTH - 2;
 
-        let height = *image_positions.iter().map(|((i, _), _)| i).max().unwrap() as usize + 1;
+        let height = *image_positions.iter().map(|((i, _), _)| i).max().unwrap() + 1;
         let height = height * IMAGE_TILE_HEIGHT;
-        let width = *image_positions.iter().map(|((_, j), _)| j).max().unwrap() as usize + 1;
+        let width = *image_positions.iter().map(|((_, j), _)| j).max().unwrap() + 1;
         let width = width * IMAGE_TILE_HEIGHT;
 
         let mut pixels = Vec::new();
@@ -352,8 +351,8 @@ impl Image {
         }
 
         for (pos, tile) in image_positions {
-            let begin_i = IMAGE_TILE_HEIGHT * pos.0 as usize;
-            let begin_j = IMAGE_TILE_WIDTH * pos.1 as usize;
+            let begin_i = IMAGE_TILE_HEIGHT * pos.0;
+            let begin_j = IMAGE_TILE_WIDTH * pos.1;
 
             for i in 0..IMAGE_TILE_HEIGHT {
                 for j in 0..IMAGE_TILE_WIDTH {
diff --git a/aoc2020/src/day24.rs b/aoc2020/src/day24.rs
index ab6cb28..ede3eb1 100644
--- a/aoc2020/src/day24.rs
+++ b/aoc2020/src/day24.rs
@@ -86,9 +86,7 @@ fn part2(input: &str) -> Result<usize> {
         let mut seen = HashSet::new();
         let mut todo: Vec<HexCoordinates> = black_tiles.iter().copied().collect();
 
-        while !todo.is_empty() {
-            let tile = todo.pop().unwrap();
-
+        while let Some(tile) = todo.pop() {
             if seen.contains(&tile) {
                 continue;
             } else {