}
fn detect_lint(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<LintTrigger> {
- // NOTE: Vectors of references are not supported. In order to avoid hitting https://github.com/rust-lang/rust/issues/34162,
- // (different unnamed lifetimes for closure arg and return type) we need to make sure the suggested
- // closure parameter is not a reference in case we suggest `Reverse`. Trying to destructure more
- // than one level of references would add some extra complexity as we would have to compensate
- // in the closure body.
-
if_chain! {
if let ExprKind::MethodCall(name_ident, _, args, _) = &expr.kind;
if let name = name_ident.ident.name.to_ident_string();
if name == "sort_by" || name == "sort_unstable_by";
if let [vec, Expr { kind: ExprKind::Closure(_, _, closure_body_id, _, _), .. }] = args;
- let vec_ty = cx.typeck_results().expr_ty(vec);
- if utils::is_type_diagnostic_item(cx, vec_ty, sym!(vec_type));
- let ty = vec_ty.walk().nth(1).unwrap().expect_ty(); // T in Vec<T>
- if !matches!(&ty.kind(), ty::Ref(..));
- if utils::is_copy(cx, ty);
+ if utils::is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(vec), sym!(vec_type));
if let closure_body = cx.tcx.hir().body(*closure_body_id);
if let &[
Param { pat: Pat { kind: PatKind::Binding(_, _, left_ident, _), .. }, ..},
let vec_name = Sugg::hir(cx, &args[0], "..").to_string();
let unstable = name == "sort_unstable_by";
- if_chain! {
- if let ExprKind::Path(QPath::Resolved(_, Path {
- segments: [PathSegment { ident: left_name, .. }], ..
- })) = &left_expr.kind;
- if left_name == left_ident;
- then {
- return Some(LintTrigger::Sort(SortDetection { vec_name, unstable }))
- } else {
- if !key_returns_borrow(cx, left_expr) {
- return Some(LintTrigger::SortByKey(SortByKeyDetection {
- vec_name,
- unstable,
- closure_arg,
- closure_body,
- reverse
- }))
- }
+ if let ExprKind::Path(QPath::Resolved(_, Path {
+ segments: [PathSegment { ident: left_name, .. }], ..
+ })) = &left_expr.kind {
+ if left_name == left_ident {
+ return Some(LintTrigger::Sort(SortDetection { vec_name, unstable }));
}
}
+
+ if !expr_borrows(cx, left_expr) {
+ return Some(LintTrigger::SortByKey(SortByKeyDetection {
+ vec_name,
+ unstable,
+ closure_arg,
+ closure_body,
+ reverse
+ }));
+ }
}
}
None
}
-fn key_returns_borrow(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
- if let Some(def_id) = utils::fn_def_id(cx, expr) {
- let output = cx.tcx.fn_sig(def_id).output();
- let ty = output.skip_binder();
- return matches!(ty.kind(), ty::Ref(..))
- || ty.walk().any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_)));
- }
-
- false
+fn expr_borrows(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ let ty = cx.typeck_results().expr_ty(expr);
+ matches!(ty.kind(), ty::Ref(..)) || ty.walk().any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_)))
}
impl LateLintPass<'_> for UnnecessarySortBy {
"use Vec::sort_by_key here instead",
"try",
format!(
- "{}.sort{}_by_key(|&{}| {})",
+ "{}.sort{}_by_key(|{}| {})",
trigger.vec_name,
if trigger.unstable { "_unstable" } else { "" },
trigger.closure_arg,
// Forward examples
vec.sort();
vec.sort_unstable();
- vec.sort_by_key(|&a| (a + 5).abs());
- vec.sort_unstable_by_key(|&a| id(-a));
+ vec.sort_by_key(|a| (a + 5).abs());
+ vec.sort_unstable_by_key(|a| id(-a));
// Reverse examples
- vec.sort_by_key(|&b| Reverse(b));
- vec.sort_by_key(|&b| Reverse((b + 5).abs()));
- vec.sort_unstable_by_key(|&b| Reverse(id(-b)));
+ vec.sort_by(|a, b| b.cmp(a)); // not linted to avoid suggesting `Reverse(b)` which would borrow
+ vec.sort_by_key(|b| Reverse((b + 5).abs()));
+ vec.sort_unstable_by_key(|b| Reverse(id(-b)));
// Negative examples (shouldn't be changed)
let c = &7;
vec.sort_by(|a, b| (b - a).cmp(&(a - b)));
vec.sort_by(|_, b| b.cmp(c));
vec.sort_unstable_by(|a, _| a.cmp(c));
- // Ignore vectors of references
+ // Vectors of references are fine as long as the resulting key does not borrow
let mut vec: Vec<&&&isize> = vec![&&&3, &&&6, &&&1, &&&2, &&&5];
- vec.sort_by(|a, b| (***a).abs().cmp(&(***b).abs()));
- vec.sort_unstable_by(|a, b| (***a).abs().cmp(&(***b).abs()));
+ vec.sort_by_key(|a| (***a).abs());
+ vec.sort_unstable_by_key(|a| (***a).abs());
+ // `Reverse(b)` would borrow in the following cases, don't lint
vec.sort_by(|a, b| b.cmp(a));
vec.sort_unstable_by(|a, b| b.cmp(a));
}
}
}
-// `Vec::sort_by_key` closure parameter is `F: FnMut(&T) -> K`
-// The suggestion is destructuring T and we know T is not a reference, so test that non-Copy T are
-// not linted.
+// The closure parameter is not dereferenced anymore, so non-Copy types can be linted
mod issue_6001 {
+ use super::*;
struct Test(String);
impl Test {
let mut args: Vec<Test> = vec![];
// Forward
- args.sort_by(|a, b| a.name().cmp(&b.name()));
- args.sort_unstable_by(|a, b| a.name().cmp(&b.name()));
+ args.sort_by_key(|a| a.name());
+ args.sort_unstable_by_key(|a| a.name());
// Reverse
- args.sort_by(|a, b| b.name().cmp(&a.name()));
- args.sort_unstable_by(|a, b| b.name().cmp(&a.name()));
+ args.sort_by_key(|b| Reverse(b.name()));
+ args.sort_unstable_by_key(|b| Reverse(b.name()));
}
}
vec.sort_by(|a, b| (a + 5).abs().cmp(&(b + 5).abs()));
vec.sort_unstable_by(|a, b| id(-a).cmp(&id(-b)));
// Reverse examples
- vec.sort_by(|a, b| b.cmp(a));
+ vec.sort_by(|a, b| b.cmp(a)); // not linted to avoid suggesting `Reverse(b)` which would borrow
vec.sort_by(|a, b| (b + 5).abs().cmp(&(a + 5).abs()));
vec.sort_unstable_by(|a, b| id(-b).cmp(&id(-a)));
// Negative examples (shouldn't be changed)
vec.sort_by(|_, b| b.cmp(c));
vec.sort_unstable_by(|a, _| a.cmp(c));
- // Ignore vectors of references
+ // Vectors of references are fine as long as the resulting key does not borrow
let mut vec: Vec<&&&isize> = vec![&&&3, &&&6, &&&1, &&&2, &&&5];
vec.sort_by(|a, b| (***a).abs().cmp(&(***b).abs()));
vec.sort_unstable_by(|a, b| (***a).abs().cmp(&(***b).abs()));
+ // `Reverse(b)` would borrow in the following cases, don't lint
vec.sort_by(|a, b| b.cmp(a));
vec.sort_unstable_by(|a, b| b.cmp(a));
}
}
}
-// `Vec::sort_by_key` closure parameter is `F: FnMut(&T) -> K`
-// The suggestion is destructuring T and we know T is not a reference, so test that non-Copy T are
-// not linted.
+// The closure parameter is not dereferenced anymore, so non-Copy types can be linted
mod issue_6001 {
+ use super::*;
struct Test(String);
impl Test {
--> $DIR/unnecessary_sort_by.rs:16:5
|
LL | vec.sort_by(|a, b| (a + 5).abs().cmp(&(b + 5).abs()));
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_by_key(|&a| (a + 5).abs())`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_by_key(|a| (a + 5).abs())`
error: use Vec::sort_by_key here instead
--> $DIR/unnecessary_sort_by.rs:17:5
|
LL | vec.sort_unstable_by(|a, b| id(-a).cmp(&id(-b)));
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_unstable_by_key(|&a| id(-a))`
-
-error: use Vec::sort_by_key here instead
- --> $DIR/unnecessary_sort_by.rs:19:5
- |
-LL | vec.sort_by(|a, b| b.cmp(a));
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_by_key(|&b| Reverse(b))`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_unstable_by_key(|a| id(-a))`
error: use Vec::sort_by_key here instead
--> $DIR/unnecessary_sort_by.rs:20:5
|
LL | vec.sort_by(|a, b| (b + 5).abs().cmp(&(a + 5).abs()));
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_by_key(|&b| Reverse((b + 5).abs()))`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_by_key(|b| Reverse((b + 5).abs()))`
error: use Vec::sort_by_key here instead
--> $DIR/unnecessary_sort_by.rs:21:5
|
LL | vec.sort_unstable_by(|a, b| id(-b).cmp(&id(-a)));
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_unstable_by_key(|&b| Reverse(id(-b)))`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_unstable_by_key(|b| Reverse(id(-b)))`
+
+error: use Vec::sort_by_key here instead
+ --> $DIR/unnecessary_sort_by.rs:31:5
+ |
+LL | vec.sort_by(|a, b| (***a).abs().cmp(&(***b).abs()));
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_by_key(|a| (***a).abs())`
+
+error: use Vec::sort_by_key here instead
+ --> $DIR/unnecessary_sort_by.rs:32:5
+ |
+LL | vec.sort_unstable_by(|a, b| (***a).abs().cmp(&(***b).abs()));
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `vec.sort_unstable_by_key(|a| (***a).abs())`
+
+error: use Vec::sort_by_key here instead
+ --> $DIR/unnecessary_sort_by.rs:88:9
+ |
+LL | args.sort_by(|a, b| a.name().cmp(&b.name()));
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `args.sort_by_key(|a| a.name())`
+
+error: use Vec::sort_by_key here instead
+ --> $DIR/unnecessary_sort_by.rs:89:9
+ |
+LL | args.sort_unstable_by(|a, b| a.name().cmp(&b.name()));
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `args.sort_unstable_by_key(|a| a.name())`
+
+error: use Vec::sort_by_key here instead
+ --> $DIR/unnecessary_sort_by.rs:91:9
+ |
+LL | args.sort_by(|a, b| b.name().cmp(&a.name()));
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `args.sort_by_key(|b| Reverse(b.name()))`
+
+error: use Vec::sort_by_key here instead
+ --> $DIR/unnecessary_sort_by.rs:92:9
+ |
+LL | args.sort_unstable_by(|a, b| b.name().cmp(&a.name()));
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `args.sort_unstable_by_key(|b| Reverse(b.name()))`
-error: aborting due to 7 previous errors
+error: aborting due to 12 previous errors
projects / rust.git / commitdiff