Add the common case search
Changes: - Refactor the common case search into a function. - Fix the useless Option around the vec in the search_same_list.
This commit is contained in:
Vincent Dal Maso
parent
bfb230369e
commit
fa9f744c2c
@ -152,7 +152,7 @@ fn lint_same_cond(cx: &LateContext<'_, '_>, conds: &[&Expr]) {
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let eq: &dyn Fn(&&Expr, &&Expr) -> bool =
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&|&lhs, &rhs| -> bool { SpanlessEq::new(cx).ignore_fn().eq_expr(lhs, rhs) };
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if let Some((i, j)) = search_same(conds, hash, eq) {
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for (i, j) in search_same(conds, hash, eq) {
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span_note_and_lint(
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cx,
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IFS_SAME_COND,
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@ -185,48 +185,47 @@ fn lint_match_arms(cx: &LateContext<'_, '_>, expr: &Expr) {
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};
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let indexed_arms: Vec<(usize, &Arm)> = arms.iter().enumerate().collect();
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search_same_list(&indexed_arms, hash, eq).map(|item| {
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for match_expr in item {
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let (&(_, i), &(_, j)) = match_expr;
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for (&(_, i), &(_, j)) in search_same(&indexed_arms, hash, eq) {
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span_lint_and_then(
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cx,
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MATCH_SAME_ARMS,
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j.body.span,
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"this `match` has identical arm bodies",
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|db| {
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db.span_note(i.body.span, "same as this");
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span_lint_and_then(
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cx,
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MATCH_SAME_ARMS,
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j.body.span,
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"this `match` has identical arm bodies",
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|db| {
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db.span_note(i.body.span, "same as this");
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// Note: this does not use `span_suggestion` on purpose:
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// there is no clean way
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// to remove the other arm. Building a span and suggest to replace it to ""
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// makes an even more confusing error message. Also in order not to make up a
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// span for the whole pattern, the suggestion is only shown when there is only
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// one pattern. The user should know about `|` if they are already using it…
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// Note: this does not use `span_suggestion` on purpose:
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// there is no clean way
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// to remove the other arm. Building a span and suggest to replace it to ""
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// makes an even more confusing error message. Also in order not to make up a
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// span for the whole pattern, the suggestion is only shown when there is only
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// one pattern. The user should know about `|` if they are already using it…
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if i.pats.len() == 1 && j.pats.len() == 1 {
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let lhs = snippet(cx, i.pats[0].span, "<pat1>");
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let rhs = snippet(cx, j.pats[0].span, "<pat2>");
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if i.pats.len() == 1 && j.pats.len() == 1 {
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let lhs = snippet(cx, i.pats[0].span, "<pat1>");
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let rhs = snippet(cx, j.pats[0].span, "<pat2>");
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if let PatKind::Wild = j.pats[0].node {
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// if the last arm is _, then i could be integrated into _
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// note that i.pats[0] cannot be _, because that would mean that we're
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// hiding all the subsequent arms, and rust won't compile
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db.span_note(
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i.body.span,
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&format!(
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"`{}` has the same arm body as the `_` wildcard, consider removing it`",
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lhs
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),
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);
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} else {
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db.span_note(i.body.span, &format!("consider refactoring into `{} | {}`", lhs, rhs));
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}
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if let PatKind::Wild = j.pats[0].node {
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// if the last arm is _, then i could be integrated into _
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// note that i.pats[0] cannot be _, because that would mean that we're
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// hiding all the subsequent arms, and rust won't compile
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db.span_note(
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i.body.span,
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&format!(
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"`{}` has the same arm body as the `_` wildcard, consider removing it`",
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lhs
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),
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);
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} else {
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db.span_help(
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i.pats[0].span,
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&format!("consider refactoring into `{} | {}`", lhs, rhs),
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);
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}
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},
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);
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}
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});
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}
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},
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);
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}
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}
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}
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@ -327,49 +326,32 @@ where
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None
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}
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fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Option<(&T, &T)>
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fn search_common_cases<'a, T, Eq>(exprs: &'a [T], eq: &Eq) -> Option<(&'a T, &'a T)>
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where
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Hash: Fn(&T) -> u64,
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Eq: Fn(&T, &T) -> bool,
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{
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// common cases
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if exprs.len() < 2 {
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return None;
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None
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} else if exprs.len() == 2 {
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return if eq(&exprs[0], &exprs[1]) {
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if eq(&exprs[0], &exprs[1]) {
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Some((&exprs[0], &exprs[1]))
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} else {
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None
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};
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}
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let mut map: FxHashMap<_, Vec<&_>> =
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FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
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for expr in exprs {
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match map.entry(hash(expr)) {
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Entry::Occupied(mut o) => {
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for o in o.get() {
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if eq(o, expr) {
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return Some((o, expr));
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}
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}
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o.get_mut().push(expr);
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},
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Entry::Vacant(v) => {
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v.insert(vec![expr]);
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},
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}
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} else {
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None
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}
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None
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}
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fn search_same_list<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Option<Vec<(&T, &T)>>
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fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
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where
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Hash: Fn(&T) -> u64,
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Eq: Fn(&T, &T) -> bool,
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{
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if let Some(expr) = search_common_cases(&exprs, &eq) {
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return vec![expr];
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}
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let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
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let mut map: FxHashMap<_, Vec<&_>> =
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@ -391,9 +373,5 @@ where
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}
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}
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if match_expr_list.is_empty() {
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None
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} else {
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Some(match_expr_list)
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}
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match_expr_list
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}
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@ -116,6 +116,14 @@ fn match_same_arms() {
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52 => 2, //~ ERROR match arms have same body
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_ => 0,
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};
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let _ = match 42 {
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1 => 2,
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2 => 2, //~ ERROR 2rd matched arms have same body
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3 => 2, //~ ERROR 3rd matched arms have same body
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4 => 3,
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_ => 0,
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};
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}
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fn main() {}
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@ -1,10 +1,48 @@
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:37:14
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LL | _ => {
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| ______________^
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LL | | //~ ERROR match arms have same body
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LL | | foo();
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LL | | let mut a = 42 + [23].len() as i32;
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... |
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LL | | a
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LL | | },
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| |_________^
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|
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= note: `-D clippy::match-same-arms` implied by `-D warnings`
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note: same as this
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--> $DIR/match_same_arms.rs:28:15
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LL | 42 => {
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| _______________^
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LL | | foo();
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LL | | let mut a = 42 + [23].len() as i32;
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LL | | if true {
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... |
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LL | | a
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LL | | },
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| |_________^
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note: `42` has the same arm body as the `_` wildcard, consider removing it`
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--> $DIR/match_same_arms.rs:28:15
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LL | 42 => {
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| _______________^
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LL | | foo();
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LL | | let mut a = 42 + [23].len() as i32;
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LL | | if true {
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... |
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LL | | a
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LL | | },
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| |_________^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:52:14
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LL | _ => 0, //~ ERROR match arms have same body
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| ^
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= note: `-D clippy::match-same-arms` implied by `-D warnings`
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note: same as this
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--> $DIR/match_same_arms.rs:50:19
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@ -27,11 +65,11 @@ note: same as this
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LL | 42 => foo(),
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| ^^^^^
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note: consider refactoring into `42 | 51`
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--> $DIR/match_same_arms.rs:56:15
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help: consider refactoring into `42 | 51`
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--> $DIR/match_same_arms.rs:56:9
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LL | 42 => foo(),
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| ^^^^^
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| ^^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:63:17
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@ -44,11 +82,11 @@ note: same as this
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LL | Some(_) => 24,
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| ^^
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note: consider refactoring into `Some(_) | None`
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--> $DIR/match_same_arms.rs:62:20
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help: consider refactoring into `Some(_) | None`
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--> $DIR/match_same_arms.rs:62:9
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LL | Some(_) => 24,
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| ^^
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| ^^^^^^^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:85:28
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@ -61,11 +99,11 @@ note: same as this
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LL | (Some(a), None) => bar(a),
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| ^^^^^^
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note: consider refactoring into `(Some(a), None) | (None, Some(a))`
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--> $DIR/match_same_arms.rs:84:28
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help: consider refactoring into `(Some(a), None) | (None, Some(a))`
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--> $DIR/match_same_arms.rs:84:9
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LL | (Some(a), None) => bar(a),
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| ^^^^^^
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| ^^^^^^^^^^^^^^^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:91:26
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@ -78,11 +116,11 @@ note: same as this
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LL | (Some(a), ..) => bar(a),
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| ^^^^^^
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note: consider refactoring into `(Some(a), ..) | (.., Some(a))`
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--> $DIR/match_same_arms.rs:90:26
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help: consider refactoring into `(Some(a), ..) | (.., Some(a))`
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--> $DIR/match_same_arms.rs:90:9
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LL | (Some(a), ..) => bar(a),
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| ^^^^^^
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| ^^^^^^^^^^^^^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:97:20
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@ -95,11 +133,11 @@ note: same as this
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LL | (1, .., 3) => 42,
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| ^^
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note: consider refactoring into `(1, .., 3) | (.., 3)`
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--> $DIR/match_same_arms.rs:96:23
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help: consider refactoring into `(1, .., 3) | (.., 3)`
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--> $DIR/match_same_arms.rs:96:9
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LL | (1, .., 3) => 42,
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| ^^
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| ^^^^^^^^^^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:114:15
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@ -112,11 +150,11 @@ note: same as this
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LL | 42 => 1,
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| ^
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note: consider refactoring into `42 | 51`
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--> $DIR/match_same_arms.rs:113:15
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help: consider refactoring into `42 | 51`
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--> $DIR/match_same_arms.rs:113:9
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LL | 42 => 1,
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| ^
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| ^^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:116:15
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@ -129,11 +167,62 @@ note: same as this
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LL | 41 => 2,
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| ^
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note: consider refactoring into `41 | 52`
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--> $DIR/match_same_arms.rs:115:15
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help: consider refactoring into `41 | 52`
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--> $DIR/match_same_arms.rs:115:9
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LL | 41 => 2,
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| ^
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| ^^
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error: aborting due to 8 previous errors
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:122:14
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LL | 2 => 2, //~ ERROR 2rd matched arms have same body
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| ^
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note: same as this
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--> $DIR/match_same_arms.rs:121:14
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LL | 1 => 2,
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| ^
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help: consider refactoring into `1 | 2`
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--> $DIR/match_same_arms.rs:121:9
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LL | 1 => 2,
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| ^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:123:14
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LL | 3 => 2, //~ ERROR 3rd matched arms have same body
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| ^
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note: same as this
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--> $DIR/match_same_arms.rs:121:14
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LL | 1 => 2,
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| ^
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help: consider refactoring into `1 | 3`
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--> $DIR/match_same_arms.rs:121:9
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LL | 1 => 2,
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| ^
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error: this `match` has identical arm bodies
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--> $DIR/match_same_arms.rs:123:14
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LL | 3 => 2, //~ ERROR 3rd matched arms have same body
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| ^
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note: same as this
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--> $DIR/match_same_arms.rs:122:14
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LL | 2 => 2, //~ ERROR 2rd matched arms have same body
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| ^
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help: consider refactoring into `2 | 3`
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--> $DIR/match_same_arms.rs:122:9
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LL | 2 => 2, //~ ERROR 2rd matched arms have same body
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| ^
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error: aborting due to 12 previous errors
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