diff options
| -rw-r--r-- | clippy_lints/src/methods/unnecessary_to_owned.rs | 56 | ||||
| -rw-r--r-- | tests/ui/unnecessary_to_owned_on_split.fixed | 21 | ||||
| -rw-r--r-- | tests/ui/unnecessary_to_owned_on_split.rs | 21 | ||||
| -rw-r--r-- | tests/ui/unnecessary_to_owned_on_split.stderr | 53 |
4 files changed, 151 insertions, 0 deletions
diff --git a/clippy_lints/src/methods/unnecessary_to_owned.rs b/clippy_lints/src/methods/unnecessary_to_owned.rs index c4775b6bd04..637368e9361 100644 --- a/clippy_lints/src/methods/unnecessary_to_owned.rs +++ b/clippy_lints/src/methods/unnecessary_to_owned.rs @@ -7,6 +7,7 @@ use clippy_utils::ty::{get_iterator_item_ty, implements_trait, is_copy, peel_mid use clippy_utils::visitors::find_all_ret_expressions; use clippy_utils::{fn_def_id, get_parent_expr, is_diag_item_method, is_diag_trait_item, return_ty}; use rustc_errors::Applicability; +use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; use rustc_hir::{BorrowKind, Expr, ExprKind, ItemKind, Node}; use rustc_hir_typeck::{FnCtxt, Inherited}; @@ -37,6 +38,9 @@ pub fn check<'tcx>( if is_cloned_or_copied(cx, method_name, method_def_id) { unnecessary_iter_cloned::check(cx, expr, method_name, receiver); } else if is_to_owned_like(cx, expr, method_name, method_def_id) { + if check_split_call_arg(cx, expr, method_name, receiver) { + return; + } // At this point, we know the call is of a `to_owned`-like function. The functions // `check_addr_of_expr` and `check_call_arg` determine whether the call is unnecessary // based on its context, that is, whether it is a referent in an `AddrOf` expression, an @@ -233,6 +237,58 @@ fn check_into_iter_call_arg( false } +/// Checks whether `expr` is an argument in an `into_iter` call and, if so, determines whether its +/// call of a `to_owned`-like function is unnecessary. +fn check_split_call_arg(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: Symbol, receiver: &Expr<'_>) -> bool { + if let Some(parent) = get_parent_expr(cx, expr) + && let Some((fn_name, argument_expr)) = get_fn_name_and_arg(cx, parent) + && fn_name.as_str() == "split" + && let Some(receiver_snippet) = snippet_opt(cx, receiver.span) + && let Some(arg_snippet) = snippet_opt(cx, argument_expr.span) + { + // The next suggestion may be incorrect because the removal of the `to_owned`-like + // function could cause the iterator to hold a reference to a resource that is used + // mutably. See https://github.com/rust-lang/rust-clippy/issues/8148. + span_lint_and_sugg( + cx, + UNNECESSARY_TO_OWNED, + parent.span, + &format!("unnecessary use of `{method_name}`"), + "use", + format!("{receiver_snippet}.split({arg_snippet})"), + Applicability::MaybeIncorrect, + ); + return true; + } + false +} + +fn get_fn_name_and_arg<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> Option<(Symbol, Expr<'tcx>)> { + match &expr.kind { + ExprKind::MethodCall(path, _, [arg_expr], ..) => Some((path.ident.name, *arg_expr)), + ExprKind::Call( + Expr { + kind: ExprKind::Path(qpath), + hir_id: path_hir_id, + .. + }, + [arg_expr], + ) => { + // Only return Fn-like DefIds, not the DefIds of statics/consts/etc that contain or + // deref to fn pointers, dyn Fn, impl Fn - #8850 + if let Res::Def(DefKind::Fn | DefKind::Ctor(..) | DefKind::AssocFn, def_id) = + cx.typeck_results().qpath_res(qpath, *path_hir_id) + && let Some(fn_name) = cx.tcx.opt_item_name(def_id) + { + Some((fn_name, *arg_expr)) + } else { + None + } + }, + _ => None, + } +} + /// Checks whether `expr` is an argument in a function call and, if so, determines whether its call /// of a `to_owned`-like function is unnecessary. fn check_other_call_arg<'tcx>( diff --git a/tests/ui/unnecessary_to_owned_on_split.fixed b/tests/ui/unnecessary_to_owned_on_split.fixed new file mode 100644 index 00000000000..53dc3c43e2f --- /dev/null +++ b/tests/ui/unnecessary_to_owned_on_split.fixed @@ -0,0 +1,21 @@ +#[allow(clippy::single_char_pattern)] + +fn main() { + let _ = "a".split('a').next().unwrap(); + //~^ ERROR: unnecessary use of `to_string` + let _ = "a".split("a").next().unwrap(); + //~^ ERROR: unnecessary use of `to_string` + let _ = "a".split('a').next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` + let _ = "a".split("a").next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` + + let _ = [1].split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_vec` + let _ = [1].split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_vec` + let _ = [1].split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` + let _ = [1].split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` +} diff --git a/tests/ui/unnecessary_to_owned_on_split.rs b/tests/ui/unnecessary_to_owned_on_split.rs new file mode 100644 index 00000000000..62400e7eee1 --- /dev/null +++ b/tests/ui/unnecessary_to_owned_on_split.rs @@ -0,0 +1,21 @@ +#[allow(clippy::single_char_pattern)] + +fn main() { + let _ = "a".to_string().split('a').next().unwrap(); + //~^ ERROR: unnecessary use of `to_string` + let _ = "a".to_string().split("a").next().unwrap(); + //~^ ERROR: unnecessary use of `to_string` + let _ = "a".to_owned().split('a').next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` + let _ = "a".to_owned().split("a").next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` + + let _ = [1].to_vec().split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_vec` + let _ = [1].to_vec().split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_vec` + let _ = [1].to_owned().split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` + let _ = [1].to_owned().split(|x| *x == 2).next().unwrap(); + //~^ ERROR: unnecessary use of `to_owned` +} diff --git a/tests/ui/unnecessary_to_owned_on_split.stderr b/tests/ui/unnecessary_to_owned_on_split.stderr new file mode 100644 index 00000000000..cfb3766d15e --- /dev/null +++ b/tests/ui/unnecessary_to_owned_on_split.stderr @@ -0,0 +1,53 @@ +error: unnecessary use of `to_string` + --> $DIR/unnecessary_to_owned_on_split.rs:4:13 + | +LL | let _ = "a".to_string().split('a').next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `"a".split('a')` + | + = note: `-D clippy::unnecessary-to-owned` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::unnecessary_to_owned)]` + +error: unnecessary use of `to_string` + --> $DIR/unnecessary_to_owned_on_split.rs:6:13 + | +LL | let _ = "a".to_string().split("a").next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `"a".split("a")` + +error: unnecessary use of `to_owned` + --> $DIR/unnecessary_to_owned_on_split.rs:8:13 + | +LL | let _ = "a".to_owned().split('a').next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `"a".split('a')` + +error: unnecessary use of `to_owned` + --> $DIR/unnecessary_to_owned_on_split.rs:10:13 + | +LL | let _ = "a".to_owned().split("a").next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `"a".split("a")` + +error: unnecessary use of `to_vec` + --> $DIR/unnecessary_to_owned_on_split.rs:13:13 + | +LL | let _ = [1].to_vec().split(|x| *x == 2).next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[1].split(|x| *x == 2)` + +error: unnecessary use of `to_vec` + --> $DIR/unnecessary_to_owned_on_split.rs:15:13 + | +LL | let _ = [1].to_vec().split(|x| *x == 2).next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[1].split(|x| *x == 2)` + +error: unnecessary use of `to_owned` + --> $DIR/unnecessary_to_owned_on_split.rs:17:13 + | +LL | let _ = [1].to_owned().split(|x| *x == 2).next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[1].split(|x| *x == 2)` + +error: unnecessary use of `to_owned` + --> $DIR/unnecessary_to_owned_on_split.rs:19:13 + | +LL | let _ = [1].to_owned().split(|x| *x == 2).next().unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[1].split(|x| *x == 2)` + +error: aborting due to 8 previous errors + |