Use checked_sub instead of wrapping_sub

casey · casey · commit 04c05f610759 · 2019-05-15T15:57:06.000-04:00
diff --git a/src/lib.rs b/src/lib.rs
@@ -72,7 +72,7 @@ fn fmt_changeset(f: &mut fmt::Formatter, changeset: &Changeset) -> fmt::Result {
                 format_same(f, text)?;
             }
             Difference::Add(added) => {
-                if let Some(Difference::Rem(removed)) = diffs.get(i.wrapping_sub(1)) {
+                if let Some(Difference::Rem(removed)) = i.checked_sub(1).map(|i| &diffs[i]) {
                     format_add_rem(f, added, removed)?;
                 } else {
                     format_add(f, added)?;

Original file line number	Diff line number	Diff line change
`@@ -72,7 +72,7 @@ fn fmt_changeset(f: &mut fmt::Formatter, changeset: &Changeset) -> fmt::Result {`
`72`	`72`	`format_same(f, text)?;`
`73`	`73`	`}`
`74`	`74`	`Difference::Add(added) => {`
`75`		`- if let Some(Difference::Rem(removed)) = diffs.get(i.wrapping_sub(1)) {`
	`75`	`+ if let Some(Difference::Rem(removed)) = i.checked_sub(1).map(\|i\| &diffs[i]) {`
`76`	`76`	`format_add_rem(f, added, removed)?;`
`77`	`77`	`} else {`
`78`	`78`	`format_add(f, added)?;`