diff options
| -rw-r--r-- | clippy_lints/src/lib.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/unused_unit.rs | 155 | ||||
| -rw-r--r-- | tests/ui/unused_unit.edition2021.fixed | 146 | ||||
| -rw-r--r-- | tests/ui/unused_unit.edition2021.stderr | 128 | ||||
| -rw-r--r-- | tests/ui/unused_unit.edition2024.fixed | 146 | ||||
| -rw-r--r-- | tests/ui/unused_unit.edition2024.stderr | 122 | ||||
| -rw-r--r-- | tests/ui/unused_unit.fixed | 21 | ||||
| -rw-r--r-- | tests/ui/unused_unit.rs | 26 | ||||
| -rw-r--r-- | tests/ui/unused_unit.stderr | 32 |
9 files changed, 698 insertions, 79 deletions
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 5fa8f6f4bf3..bc7fc60827a 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -729,6 +729,7 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) { store.register_early_pass(|| Box::new(misc_early::MiscEarlyLints)); store.register_late_pass(|_| Box::new(redundant_closure_call::RedundantClosureCall)); store.register_early_pass(|| Box::new(unused_unit::UnusedUnit)); + store.register_late_pass(|_| Box::new(unused_unit::UnusedUnit)); store.register_late_pass(|_| Box::new(returns::Return)); store.register_late_pass(move |tcx| Box::new(collapsible_if::CollapsibleIf::new(tcx, conf))); store.register_late_pass(|_| Box::new(items_after_statements::ItemsAfterStatements)); diff --git a/clippy_lints/src/unused_unit.rs b/clippy_lints/src/unused_unit.rs index d5309aade7a..9859ddfdf7b 100644 --- a/clippy_lints/src/unused_unit.rs +++ b/clippy_lints/src/unused_unit.rs @@ -1,11 +1,18 @@ use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::source::{SpanRangeExt, position_before_rarrow}; -use rustc_ast::visit::FnKind; -use rustc_ast::{ClosureBinder, ast}; +use clippy_utils::{is_never_expr, is_unit_expr}; +use rustc_ast::{Block, StmtKind}; use rustc_errors::Applicability; -use rustc_lint::{EarlyContext, EarlyLintPass}; +use rustc_hir::def_id::LocalDefId; +use rustc_hir::intravisit::FnKind; +use rustc_hir::{ + AssocItemConstraintKind, Body, Expr, ExprKind, FnDecl, FnRetTy, GenericArgsParentheses, Node, PolyTraitRef, Term, + Ty, TyKind, +}; +use rustc_lint::{EarlyContext, EarlyLintPass, LateContext, LateLintPass}; use rustc_session::declare_lint_pass; -use rustc_span::{BytePos, Span}; +use rustc_span::edition::Edition; +use rustc_span::{BytePos, Span, sym}; declare_clippy_lint! { /// ### What it does @@ -34,27 +41,89 @@ declare_clippy_lint! { declare_lint_pass!(UnusedUnit => [UNUSED_UNIT]); -impl EarlyLintPass for UnusedUnit { - fn check_fn(&mut self, cx: &EarlyContext<'_>, kind: FnKind<'_>, span: Span, _: ast::NodeId) { - if let ast::FnRetTy::Ty(ref ty) = kind.decl().output - && let ast::TyKind::Tup(ref vals) = ty.kind - && vals.is_empty() - && !ty.span.from_expansion() - && get_def(span) == get_def(ty.span) +impl<'tcx> LateLintPass<'tcx> for UnusedUnit { + fn check_fn( + &mut self, + cx: &LateContext<'tcx>, + kind: FnKind<'tcx>, + decl: &'tcx FnDecl<'tcx>, + body: &'tcx Body<'tcx>, + span: Span, + def_id: LocalDefId, + ) { + if let FnRetTy::Return(hir_ty) = decl.output + && is_unit_ty(hir_ty) + && !hir_ty.span.from_expansion() + && get_def(span) == get_def(hir_ty.span) { // implicit types in closure signatures are forbidden when `for<...>` is present - if let FnKind::Closure(&ClosureBinder::For { .. }, ..) = kind { + if let FnKind::Closure = kind + && let Node::Expr(expr) = cx.tcx.hir_node_by_def_id(def_id) + && let ExprKind::Closure(closure) = expr.kind + && !closure.bound_generic_params.is_empty() + { + return; + } + + // unit never type fallback is no longer supported since Rust 2024. For more information, + // see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/never-type-fallback.html> + if cx.tcx.sess.edition() >= Edition::Edition2024 + && let ExprKind::Block(block, _) = body.value.kind + && let Some(expr) = block.expr + && is_never_expr(cx, expr).is_some() + { return; } - lint_unneeded_unit_return(cx, ty, span); + lint_unneeded_unit_return(cx, hir_ty.span, span); } } - fn check_block(&mut self, cx: &EarlyContext<'_>, block: &ast::Block) { - if let Some(stmt) = block.stmts.last() - && let ast::StmtKind::Expr(ref expr) = stmt.kind + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) { + if let ExprKind::Ret(Some(expr)) | ExprKind::Break(_, Some(expr)) = expr.kind && is_unit_expr(expr) + && !expr.span.from_expansion() + { + span_lint_and_sugg( + cx, + UNUSED_UNIT, + expr.span, + "unneeded `()`", + "remove the `()`", + String::new(), + Applicability::MachineApplicable, + ); + } + } + + fn check_poly_trait_ref(&mut self, cx: &LateContext<'tcx>, poly: &'tcx PolyTraitRef<'tcx>) { + let segments = &poly.trait_ref.path.segments; + + if segments.len() == 1 + && ["Fn", "FnMut", "FnOnce"].contains(&segments[0].ident.name.as_str()) + && let Some(args) = segments[0].args + && args.parenthesized == GenericArgsParentheses::ParenSugar + && let constraints = &args.constraints + && constraints.len() == 1 + && constraints[0].ident.name == sym::Output + && let AssocItemConstraintKind::Equality { term: Term::Ty(hir_ty) } = constraints[0].kind + && args.span_ext.hi() != poly.span.hi() + && !hir_ty.span.from_expansion() + && is_unit_ty(hir_ty) + { + lint_unneeded_unit_return(cx, hir_ty.span, poly.span); + } + } +} + +impl EarlyLintPass for UnusedUnit { + /// Check for unit expressions in blocks. This is left in the early pass because some macros + /// expand its inputs as-is, making it invisible to the late pass. See #4076. + fn check_block(&mut self, cx: &EarlyContext<'_>, block: &Block) { + if let Some(stmt) = block.stmts.last() + && let StmtKind::Expr(expr) = &stmt.kind + && let rustc_ast::ExprKind::Tup(inner) = &expr.kind + && inner.is_empty() && let ctxt = block.span.ctxt() && stmt.span.ctxt() == ctxt && expr.span.ctxt() == ctxt @@ -72,39 +141,10 @@ impl EarlyLintPass for UnusedUnit { ); } } +} - fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) { - match e.kind { - ast::ExprKind::Ret(Some(ref expr)) | ast::ExprKind::Break(_, Some(ref expr)) => { - if is_unit_expr(expr) && !expr.span.from_expansion() { - span_lint_and_sugg( - cx, - UNUSED_UNIT, - expr.span, - "unneeded `()`", - "remove the `()`", - String::new(), - Applicability::MachineApplicable, - ); - } - }, - _ => (), - } - } - - fn check_poly_trait_ref(&mut self, cx: &EarlyContext<'_>, poly: &ast::PolyTraitRef) { - let segments = &poly.trait_ref.path.segments; - - if segments.len() == 1 - && ["Fn", "FnMut", "FnOnce"].contains(&segments[0].ident.name.as_str()) - && let Some(args) = &segments[0].args - && let ast::GenericArgs::Parenthesized(generic_args) = &**args - && let ast::FnRetTy::Ty(ty) = &generic_args.output - && ty.kind.is_unit() - { - lint_unneeded_unit_return(cx, ty, generic_args.span); - } - } +fn is_unit_ty(ty: &Ty<'_>) -> bool { + matches!(ty.kind, TyKind::Tup([])) } // get the def site @@ -117,24 +157,15 @@ fn get_def(span: Span) -> Option<Span> { } } -// is this expr a `()` unit? -fn is_unit_expr(expr: &ast::Expr) -> bool { - if let ast::ExprKind::Tup(ref vals) = expr.kind { - vals.is_empty() - } else { - false - } -} - -fn lint_unneeded_unit_return(cx: &EarlyContext<'_>, ty: &ast::Ty, span: Span) { +fn lint_unneeded_unit_return(cx: &LateContext<'_>, ty_span: Span, span: Span) { let (ret_span, appl) = - span.with_hi(ty.span.hi()) + span.with_hi(ty_span.hi()) .get_source_text(cx) - .map_or((ty.span, Applicability::MaybeIncorrect), |src| { - position_before_rarrow(&src).map_or((ty.span, Applicability::MaybeIncorrect), |rpos| { + .map_or((ty_span, Applicability::MaybeIncorrect), |src| { + position_before_rarrow(&src).map_or((ty_span, Applicability::MaybeIncorrect), |rpos| { ( #[expect(clippy::cast_possible_truncation)] - ty.span.with_lo(BytePos(span.lo().0 + rpos as u32)), + ty_span.with_lo(BytePos(span.lo().0 + rpos as u32)), Applicability::MachineApplicable, ) }) diff --git a/tests/ui/unused_unit.edition2021.fixed b/tests/ui/unused_unit.edition2021.fixed new file mode 100644 index 00000000000..93dd58b8e9d --- /dev/null +++ b/tests/ui/unused_unit.edition2021.fixed @@ -0,0 +1,146 @@ +//@revisions: edition2021 edition2024 +//@[edition2021] edition:2021 +//@[edition2024] edition:2024 + +// The output for humans should just highlight the whole span without showing +// the suggested replacement, but we also want to test that suggested +// replacement only removes one set of parentheses, rather than naïvely +// stripping away any starting or ending parenthesis characters—hence this +// test of the JSON error format. + +#![feature(custom_inner_attributes)] +#![feature(closure_lifetime_binder)] +#![rustfmt::skip] + +#![deny(clippy::unused_unit)] +#![allow(dead_code)] +#![allow(clippy::from_over_into)] + +struct Unitter; +impl Unitter { + #[allow(clippy::no_effect)] + pub fn get_unit<F: Fn(), G>(&self, f: F, _g: G) + //~^ unused_unit + //~| unused_unit + where G: Fn() { + //~^ unused_unit + let _y: &dyn Fn() = &f; + //~^ unused_unit + (); // this should not lint, as it's not in return type position + } +} + +impl Into<()> for Unitter { + #[rustfmt::skip] + fn into(self) { + //~^ unused_unit + + //~^ unused_unit + } +} + +trait Trait { + fn redundant<F: FnOnce(), G, H>(&self, _f: F, _g: G, _h: H) + //~^ unused_unit + where + G: FnMut(), + //~^ unused_unit + H: Fn(); + //~^ unused_unit +} + +impl Trait for Unitter { + fn redundant<F: FnOnce(), G, H>(&self, _f: F, _g: G, _h: H) + //~^ unused_unit + where + G: FnMut(), + //~^ unused_unit + H: Fn() {} + //~^ unused_unit +} + +fn return_unit() { } +//~^ unused_unit +//~| unused_unit + +#[allow(clippy::needless_return)] +#[allow(clippy::never_loop)] +#[allow(clippy::unit_cmp)] +fn main() { + let u = Unitter; + assert_eq!(u.get_unit(|| {}, return_unit), u.into()); + return_unit(); + loop { + break; + //~^ unused_unit + } + return; + //~^ unused_unit +} + +// https://github.com/rust-lang/rust-clippy/issues/4076 +fn foo() { + macro_rules! foo { + (recv($r:expr) -> $res:pat => $body:expr) => { + $body + } + } + + foo! { + recv(rx) -> _x => () + } +} + +#[rustfmt::skip] +fn test(){} +//~^ unused_unit + +#[rustfmt::skip] +fn test2(){} +//~^ unused_unit + +#[rustfmt::skip] +fn test3(){} +//~^ unused_unit + +fn macro_expr() { + macro_rules! e { + () => (()); + } + e!() +} + +mod issue9748 { + fn main() { + let _ = for<'a> |_: &'a u32| -> () {}; + } +} + +mod issue9949 { + fn main() { + #[doc = "documentation"] + () + } +} + +mod issue14577 { + trait Unit {} + impl Unit for () {} + + fn run<R: Unit>(f: impl FnOnce() -> R) { + f(); + } + + #[allow(dependency_on_unit_never_type_fallback)] + fn bar() { + run(|| { todo!() }); + //~[edition2021]^ unused_unit + } + + struct UnitStruct; + impl UnitStruct { + fn apply<F: for<'c> Fn(&'c mut Self)>(&mut self, f: F) { + todo!() + } + } +} \ No newline at end of file diff --git a/tests/ui/unused_unit.edition2021.stderr b/tests/ui/unused_unit.edition2021.stderr new file mode 100644 index 00000000000..13cc20d4d7a --- /dev/null +++ b/tests/ui/unused_unit.edition2021.stderr @@ -0,0 +1,128 @@ +error: unneeded unit expression + --> tests/ui/unused_unit.rs:37:9 + | +LL | () + | ^^ help: remove the final `()` + | +note: the lint level is defined here + --> tests/ui/unused_unit.rs:15:9 + | +LL | #![deny(clippy::unused_unit)] + | ^^^^^^^^^^^^^^^^^^^ + +error: unneeded unit expression + --> tests/ui/unused_unit.rs:62:26 + | +LL | fn return_unit() -> () { () } + | ^^ help: remove the final `()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:22:28 + | +LL | pub fn get_unit<F: Fn() -> (), G>(&self, f: F, _g: G) -> () + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:25:18 + | +LL | where G: Fn() -> () { + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:22:58 + | +LL | pub fn get_unit<F: Fn() -> (), G>(&self, f: F, _g: G) -> () + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:27:26 + | +LL | let _y: &dyn Fn() -> () = &f; + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:35:18 + | +LL | fn into(self) -> () { + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:43:29 + | +LL | fn redundant<F: FnOnce() -> (), G, H>(&self, _f: F, _g: G, _h: H) + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:46:19 + | +LL | G: FnMut() -> (), + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:48:16 + | +LL | H: Fn() -> (); + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:53:29 + | +LL | fn redundant<F: FnOnce() -> (), G, H>(&self, _f: F, _g: G, _h: H) + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:56:19 + | +LL | G: FnMut() -> (), + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:58:16 + | +LL | H: Fn() -> () {} + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:62:17 + | +LL | fn return_unit() -> () { () } + | ^^^^^^ help: remove the `-> ()` + +error: unneeded `()` + --> tests/ui/unused_unit.rs:74:14 + | +LL | break(); + | ^^ help: remove the `()` + +error: unneeded `()` + --> tests/ui/unused_unit.rs:77:11 + | +LL | return(); + | ^^ help: remove the `()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:95:10 + | +LL | fn test()->(){} + | ^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:99:11 + | +LL | fn test2() ->(){} + | ^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:103:11 + | +LL | fn test3()-> (){} + | ^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:136:15 + | +LL | run(|| -> () { todo!() }); + | ^^^^^^ help: remove the `-> ()` + +error: aborting due to 20 previous errors + diff --git a/tests/ui/unused_unit.edition2024.fixed b/tests/ui/unused_unit.edition2024.fixed new file mode 100644 index 00000000000..987d901b97d --- /dev/null +++ b/tests/ui/unused_unit.edition2024.fixed @@ -0,0 +1,146 @@ +//@revisions: edition2021 edition2024 +//@[edition2021] edition:2021 +//@[edition2024] edition:2024 + +// The output for humans should just highlight the whole span without showing +// the suggested replacement, but we also want to test that suggested +// replacement only removes one set of parentheses, rather than naïvely +// stripping away any starting or ending parenthesis characters—hence this +// test of the JSON error format. + +#![feature(custom_inner_attributes)] +#![feature(closure_lifetime_binder)] +#![rustfmt::skip] + +#![deny(clippy::unused_unit)] +#![allow(dead_code)] +#![allow(clippy::from_over_into)] + +struct Unitter; +impl Unitter { + #[allow(clippy::no_effect)] + pub fn get_unit<F: Fn(), G>(&self, f: F, _g: G) + //~^ unused_unit + //~| unused_unit + where G: Fn() { + //~^ unused_unit + let _y: &dyn Fn() = &f; + //~^ unused_unit + (); // this should not lint, as it's not in return type position + } +} + +impl Into<()> for Unitter { + #[rustfmt::skip] + fn into(self) { + //~^ unused_unit + + //~^ unused_unit + } +} + +trait Trait { + fn redundant<F: FnOnce(), G, H>(&self, _f: F, _g: G, _h: H) + //~^ unused_unit + where + G: FnMut(), + //~^ unused_unit + H: Fn(); + //~^ unused_unit +} + +impl Trait for Unitter { + fn redundant<F: FnOnce(), G, H>(&self, _f: F, _g: G, _h: H) + //~^ unused_unit + where + G: FnMut(), + //~^ unused_unit + H: Fn() {} + //~^ unused_unit +} + +fn return_unit() { } +//~^ unused_unit +//~| unused_unit + +#[allow(clippy::needless_return)] +#[allow(clippy::never_loop)] +#[allow(clippy::unit_cmp)] +fn main() { + let u = Unitter; + assert_eq!(u.get_unit(|| {}, return_unit), u.into()); + return_unit(); + loop { + break; + //~^ unused_unit + } + return; + //~^ unused_unit +} + +// https://github.com/rust-lang/rust-clippy/issues/4076 +fn foo() { + macro_rules! foo { + (recv($r:expr) -> $res:pat => $body:expr) => { + $body + } + } + + foo! { + recv(rx) -> _x => () + } +} + +#[rustfmt::skip] +fn test(){} +//~^ unused_unit + +#[rustfmt::skip] +fn test2(){} +//~^ unused_unit + +#[rustfmt::skip] +fn test3(){} +//~^ unused_unit + +fn macro_expr() { + macro_rules! e { + () => (()); + } + e!() +} + +mod issue9748 { + fn main() { + let _ = for<'a> |_: &'a u32| -> () {}; + } +} + +mod issue9949 { + fn main() { + #[doc = "documentation"] + () + } +} + +mod issue14577 { + trait Unit {} + impl Unit for () {} + + fn run<R: Unit>(f: impl FnOnce() -> R) { + f(); + } + + #[allow(dependency_on_unit_never_type_fallback)] + fn bar() { + run(|| -> () { todo!() }); + //~[edition2021]^ unused_unit + } + + struct UnitStruct; + impl UnitStruct { + fn apply<F: for<'c> Fn(&'c mut Self)>(&mut self, f: F) { + todo!() + } + } +} \ No newline at end of file diff --git a/tests/ui/unused_unit.edition2024.stderr b/tests/ui/unused_unit.edition2024.stderr new file mode 100644 index 00000000000..a79e70e066b --- /dev/null +++ b/tests/ui/unused_unit.edition2024.stderr @@ -0,0 +1,122 @@ +error: unneeded unit expression + --> tests/ui/unused_unit.rs:37:9 + | +LL | () + | ^^ help: remove the final `()` + | +note: the lint level is defined here + --> tests/ui/unused_unit.rs:15:9 + | +LL | #![deny(clippy::unused_unit)] + | ^^^^^^^^^^^^^^^^^^^ + +error: unneeded unit expression + --> tests/ui/unused_unit.rs:62:26 + | +LL | fn return_unit() -> () { () } + | ^^ help: remove the final `()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:22:28 + | +LL | pub fn get_unit<F: Fn() -> (), G>(&self, f: F, _g: G) -> () + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:25:18 + | +LL | where G: Fn() -> () { + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:22:58 + | +LL | pub fn get_unit<F: Fn() -> (), G>(&self, f: F, _g: G) -> () + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:27:26 + | +LL | let _y: &dyn Fn() -> () = &f; + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:35:18 + | +LL | fn into(self) -> () { + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:43:29 + | +LL | fn redundant<F: FnOnce() -> (), G, H>(&self, _f: F, _g: G, _h: H) + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:46:19 + | +LL | G: FnMut() -> (), + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:48:16 + | +LL | H: Fn() -> (); + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:53:29 + | +LL | fn redundant<F: FnOnce() -> (), G, H>(&self, _f: F, _g: G, _h: H) + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:56:19 + | +LL | G: FnMut() -> (), + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:58:16 + | +LL | H: Fn() -> () {} + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:62:17 + | +LL | fn return_unit() -> () { () } + | ^^^^^^ help: remove the `-> ()` + +error: unneeded `()` + --> tests/ui/unused_unit.rs:74:14 + | +LL | break(); + | ^^ help: remove the `()` + +error: unneeded `()` + --> tests/ui/unused_unit.rs:77:11 + | +LL | return(); + | ^^ help: remove the `()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:95:10 + | +LL | fn test()->(){} + | ^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:99:11 + | +LL | fn test2() ->(){} + | ^^^^^ help: remove the `-> ()` + +error: unneeded unit return type + --> tests/ui/unused_unit.rs:103:11 + | +LL | fn test3()-> (){} + | ^^^^^ help: remove the `-> ()` + +error: aborting due to 19 previous errors + diff --git a/tests/ui/unused_unit.fixed b/tests/ui/unused_unit.fixed index e3c02681c9f..6668bf90c09 100644 --- a/tests/ui/unused_unit.fixed +++ b/tests/ui/unused_unit.fixed @@ -120,3 +120,24 @@ mod issue9949 { () } } + +#[clippy::msrv = "1.85"] +mod issue14577 { + trait Unit {} + impl Unit for () {} + + fn run<R: Unit>(f: impl FnOnce() -> R) { + f(); + } + + fn bar() { + run(|| -> () { todo!() }); + } + + struct UnitStruct; + impl UnitStruct { + fn apply<F: for<'c> Fn(&'c mut Self)>(&mut self, f: F) { + todo!() + } + } +} \ No newline at end of file diff --git a/tests/ui/unused_unit.rs b/tests/ui/unused_unit.rs index 4353026c594..b7645f7b6a2 100644 --- a/tests/ui/unused_unit.rs +++ b/tests/ui/unused_unit.rs @@ -1,4 +1,6 @@ - +//@revisions: edition2021 edition2024 +//@[edition2021] edition:2021 +//@[edition2024] edition:2024 // The output for humans should just highlight the whole span without showing // the suggested replacement, but we also want to test that suggested @@ -120,3 +122,25 @@ mod issue9949 { () } } + +mod issue14577 { + trait Unit {} + impl Unit for () {} + + fn run<R: Unit>(f: impl FnOnce() -> R) { + f(); + } + + #[allow(dependency_on_unit_never_type_fallback)] + fn bar() { + run(|| -> () { todo!() }); + //~[edition2021]^ unused_unit + } + + struct UnitStruct; + impl UnitStruct { + fn apply<F: for<'c> Fn(&'c mut Self)>(&mut self, f: F) { + todo!() + } + } +} \ No newline at end of file diff --git a/tests/ui/unused_unit.stderr b/tests/ui/unused_unit.stderr index 172fe065502..366f2142095 100644 --- a/tests/ui/unused_unit.stderr +++ b/tests/ui/unused_unit.stderr @@ -1,8 +1,8 @@ -error: unneeded unit return type - --> tests/ui/unused_unit.rs:20:58 +error: unneeded unit expression + --> tests/ui/unused_unit.rs:35:9 | -LL | pub fn get_unit<F: Fn() -> (), G>(&self, f: F, _g: G) -> () - | ^^^^^^ help: remove the `-> ()` +LL | () + | ^^ help: remove the final `()` | note: the lint level is defined here --> tests/ui/unused_unit.rs:13:9 @@ -10,6 +10,12 @@ note: the lint level is defined here LL | #![deny(clippy::unused_unit)] | ^^^^^^^^^^^^^^^^^^^ +error: unneeded unit expression + --> tests/ui/unused_unit.rs:60:26 + | +LL | fn return_unit() -> () { () } + | ^^ help: remove the final `()` + error: unneeded unit return type --> tests/ui/unused_unit.rs:20:28 | @@ -23,6 +29,12 @@ LL | where G: Fn() -> () { | ^^^^^^ help: remove the `-> ()` error: unneeded unit return type + --> tests/ui/unused_unit.rs:20:58 + | +LL | pub fn get_unit<F: Fn() -> (), G>(&self, f: F, _g: G) -> () + | ^^^^^^ help: remove the `-> ()` + +error: unneeded unit return type --> tests/ui/unused_unit.rs:25:26 | LL | let _y: &dyn Fn() -> () = &f; @@ -34,12 +46,6 @@ error: unneeded unit return type LL | fn into(self) -> () { | ^^^^^^ help: remove the `-> ()` -error: unneeded unit expression - --> tests/ui/unused_unit.rs:35:9 - | -LL | () - | ^^ help: remove the final `()` - error: unneeded unit return type --> tests/ui/unused_unit.rs:41:29 | @@ -82,12 +88,6 @@ error: unneeded unit return type LL | fn return_unit() -> () { () } | ^^^^^^ help: remove the `-> ()` -error: unneeded unit expression - --> tests/ui/unused_unit.rs:60:26 - | -LL | fn return_unit() -> () { () } - | ^^ help: remove the final `()` - error: unneeded `()` --> tests/ui/unused_unit.rs:72:14 | |