Fix is_odd so it actually does something.

Author: Byron

src/myers.rs

@@ -105,7 +105,7 @@ impl Myers {
             unsafe { MiddleSnakeSearch::<false>::new(self.kforward, file1, file2) };
         let mut backwards_search =
             unsafe { MiddleSnakeSearch::<true>::new(self.kbackward, file1, file2) };
-        let is_odd = (file2.len() - file2.len()) & 1 != 0;
+        let is_odd = file2.len().wrapping_sub(file1.len()) & 1 != 0;
 
         let mut ec = 0;
 

src/myers/slice.rs

@@ -27,7 +27,7 @@ impl<'a> FileSlice<'a> {
         }
     }
 
-    pub fn borrow(&mut self) -> FileSlice {
+    pub fn borrow(&'_ mut self) -> FileSlice<'_> {
         FileSlice {
             tokens: self.tokens,
             changed: self.changed,