diff --git a/src/filters.rs b/src/filters.rs
index 527f4fbd..517148fc 100644
--- a/src/filters.rs
+++ b/src/filters.rs
@@ -71,42 +71,42 @@ pub fn unfilter_line(filter: u8, bpp: usize, data: &[u8], last_line: &[u8], buf:
             buf.extend_from_slice(data);
         }
         1 => {
-            for (i, byte) in data.iter().enumerate() {
+            for (i, &cur) in data.iter().enumerate() {
                 buf.push(match i.checked_sub(bpp) {
                     Some(x) => {
                         let b = buf[x];
-                        byte.wrapping_add(b)
+                        cur.wrapping_add(b)
                     }
-                    None => *byte,
+                    None => cur,
                 });
             }
         }
         2 => {
             buf.extend(
                 data.iter()
-                    .zip(last_line.iter())
-                    .map(|(cur, last)| cur.wrapping_add(*last)),
+                    .zip(last_line)
+                    .map(|(&cur, &last)| cur.wrapping_add(last)),
             );
         }
         3 => {
-            for (i, byte) in data.iter().enumerate() {
+            for (i, (&cur, &last)) in data.iter().zip(last_line).enumerate() {
                 buf.push(match i.checked_sub(bpp) {
                     Some(x) => {
                         let b = buf[x];
-                        byte.wrapping_add(((u16::from(b) + u16::from(last_line[i])) >> 1) as u8)
+                        cur.wrapping_add(((u16::from(b) + u16::from(last)) >> 1) as u8)
                     }
-                    None => byte.wrapping_add(last_line[i] >> 1),
+                    None => cur.wrapping_add(last >> 1),
                 });
             }
         }
         4 => {
-            for (i, byte) in data.iter().enumerate() {
+            for (i, (&cur, &last)) in data.iter().zip(last_line).enumerate() {
                 buf.push(match i.checked_sub(bpp) {
                     Some(x) => {
                         let b = buf[x];
-                        byte.wrapping_add(paeth_predictor(b, last_line[i], last_line[x]))
+                        cur.wrapping_add(paeth_predictor(b, last, last_line[x]))
                     }
-                    None => byte.wrapping_add(last_line[i]),
+                    None => cur.wrapping_add(last),
                 });
             }
         }