diff --git a/clippy_lints/src/eta_reduction.rs b/clippy_lints/src/eta_reduction.rs index 1a722d39f730..c461732fd369 100644 --- a/clippy_lints/src/eta_reduction.rs +++ b/clippy_lints/src/eta_reduction.rs @@ -10,6 +10,8 @@ use crate::utils::{ implements_trait, is_adjusted, iter_input_pats, snippet_opt, span_lint_and_sugg, span_lint_and_then, type_is_unsafe_function, }; +use clippy_utils::higher; +use clippy_utils::higher::VecArgs; declare_clippy_lint! { /// **What it does:** Checks for closures which just call another function where @@ -74,7 +76,10 @@ impl<'tcx> LateLintPass<'tcx> for EtaReduction { match expr.kind { ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) => { for arg in args { - check_closure(cx, arg) + // skip `foo(macro!())` + if arg.span.ctxt() == expr.span.ctxt() { + check_closure(cx, arg) + } } }, _ => (), @@ -87,6 +92,23 @@ fn check_closure(cx: &LateContext<'_>, expr: &Expr<'_>) { let body = cx.tcx.hir().body(eid); let ex = &body.value; + if ex.span.ctxt() != expr.span.ctxt() { + if let Some(VecArgs::Vec(&[])) = higher::vec_macro(cx, ex) { + // replace `|| vec![]` with `Vec::new` + span_lint_and_sugg( + cx, + REDUNDANT_CLOSURE, + expr.span, + "redundant closure", + "replace the closure with `Vec::new`", + "std::vec::Vec::new".into(), + Applicability::MachineApplicable, + ); + } + // skip `foo(|| macro!())` + return; + } + if_chain!( if let ExprKind::Call(ref caller, ref args) = ex.kind; @@ -107,11 +129,11 @@ fn check_closure(cx: &LateContext<'_>, expr: &Expr<'_>) { if compare_inputs(&mut iter_input_pats(decl, body), &mut args.iter()); then { - span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure found", |diag| { + span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure", |diag| { if let Some(snippet) = snippet_opt(cx, caller.span) { diag.span_suggestion( expr.span, - "remove closure as shown", + "replace the closure with the function itself", snippet, Applicability::MachineApplicable, ); @@ -141,8 +163,8 @@ fn check_closure(cx: &LateContext<'_>, expr: &Expr<'_>) { cx, REDUNDANT_CLOSURE_FOR_METHOD_CALLS, expr.span, - "redundant closure found", - "remove closure as shown", + "redundant closure", + "replace the closure with the method itself", format!("{}::{}", name, path.ident.name), Applicability::MachineApplicable, ); diff --git a/tests/ui/eta.fixed b/tests/ui/eta.fixed index 1b34c2f74eba..2be2283e3fdd 100644 --- a/tests/ui/eta.fixed +++ b/tests/ui/eta.fixed @@ -16,10 +16,25 @@ use std::path::PathBuf; +macro_rules! mac { + () => { + foobar() + }; +} + +macro_rules! closure_mac { + () => { + |n| foo(n) + }; +} + fn main() { let a = Some(1u8).map(foo); meta(foo); let c = Some(1u8).map(|a| {1+2; foo}(a)); + true.then(|| mac!()); // don't lint function in macro expansion + Some(1).map(closure_mac!()); // don't lint closure in macro expansion + let _: Option> = true.then(std::vec::Vec::new); // special case vec! let d = Some(1u8).map(|a| foo((|b| foo2(b))(a))); //is adjusted? all(&[1, 2, 3], &2, |x, y| below(x, y)); //is adjusted unsafe { diff --git a/tests/ui/eta.rs b/tests/ui/eta.rs index 4f050bd8479a..f0373f9ccf67 100644 --- a/tests/ui/eta.rs +++ b/tests/ui/eta.rs @@ -16,10 +16,25 @@ use std::path::PathBuf; +macro_rules! mac { + () => { + foobar() + }; +} + +macro_rules! closure_mac { + () => { + |n| foo(n) + }; +} + fn main() { let a = Some(1u8).map(|a| foo(a)); meta(|a| foo(a)); let c = Some(1u8).map(|a| {1+2; foo}(a)); + true.then(|| mac!()); // don't lint function in macro expansion + Some(1).map(closure_mac!()); // don't lint closure in macro expansion + let _: Option> = true.then(|| vec![]); // special case vec! let d = Some(1u8).map(|a| foo((|b| foo2(b))(a))); //is adjusted? all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted unsafe { diff --git a/tests/ui/eta.stderr b/tests/ui/eta.stderr index 16aa1b07733d..57ed65279666 100644 --- a/tests/ui/eta.stderr +++ b/tests/ui/eta.stderr @@ -1,80 +1,86 @@ -error: redundant closure found - --> $DIR/eta.rs:20:27 +error: redundant closure + --> $DIR/eta.rs:32:27 | LL | let a = Some(1u8).map(|a| foo(a)); - | ^^^^^^^^^^ help: remove closure as shown: `foo` + | ^^^^^^^^^^ help: replace the closure with the function itself: `foo` | = note: `-D clippy::redundant-closure` implied by `-D warnings` -error: redundant closure found - --> $DIR/eta.rs:21:10 +error: redundant closure + --> $DIR/eta.rs:33:10 | LL | meta(|a| foo(a)); - | ^^^^^^^^^^ help: remove closure as shown: `foo` + | ^^^^^^^^^^ help: replace the closure with the function itself: `foo` + +error: redundant closure + --> $DIR/eta.rs:37:40 + | +LL | let _: Option> = true.then(|| vec![]); // special case vec! + | ^^^^^^^^^ help: replace the closure with `Vec::new`: `std::vec::Vec::new` error: this expression borrows a reference (`&u8`) that is immediately dereferenced by the compiler - --> $DIR/eta.rs:24:21 + --> $DIR/eta.rs:39:21 | LL | all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted | ^^^ help: change this to: `&2` | = note: `-D clippy::needless-borrow` implied by `-D warnings` -error: redundant closure found - --> $DIR/eta.rs:31:27 +error: redundant closure + --> $DIR/eta.rs:46:27 | LL | let e = Some(1u8).map(|a| generic(a)); - | ^^^^^^^^^^^^^^ help: remove closure as shown: `generic` + | ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `generic` -error: redundant closure found - --> $DIR/eta.rs:74:51 +error: redundant closure + --> $DIR/eta.rs:89:51 | LL | let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo()); - | ^^^^^^^^^^^ help: remove closure as shown: `TestStruct::foo` + | ^^^^^^^^^^^ help: replace the closure with the method itself: `TestStruct::foo` | = note: `-D clippy::redundant-closure-for-method-calls` implied by `-D warnings` -error: redundant closure found - --> $DIR/eta.rs:76:51 +error: redundant closure + --> $DIR/eta.rs:91:51 | LL | let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo()); - | ^^^^^^^^^^^^^^^^^ help: remove closure as shown: `TestTrait::trait_foo` + | ^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `TestTrait::trait_foo` -error: redundant closure found - --> $DIR/eta.rs:79:42 +error: redundant closure + --> $DIR/eta.rs:94:42 | LL | let e = Some(&mut vec![1, 2, 3]).map(|v| v.clear()); - | ^^^^^^^^^^^^^ help: remove closure as shown: `std::vec::Vec::clear` + | ^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::vec::Vec::clear` -error: redundant closure found - --> $DIR/eta.rs:84:29 +error: redundant closure + --> $DIR/eta.rs:99:29 | LL | let e = Some("str").map(|s| s.to_string()); - | ^^^^^^^^^^^^^^^^^ help: remove closure as shown: `std::string::ToString::to_string` + | ^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::string::ToString::to_string` -error: redundant closure found - --> $DIR/eta.rs:86:27 +error: redundant closure + --> $DIR/eta.rs:101:27 | LL | let e = Some('a').map(|s| s.to_uppercase()); - | ^^^^^^^^^^^^^^^^^^^^ help: remove closure as shown: `char::to_uppercase` + | ^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_uppercase` -error: redundant closure found - --> $DIR/eta.rs:89:65 +error: redundant closure + --> $DIR/eta.rs:104:65 | LL | let e: std::vec::Vec = vec!['a', 'b', 'c'].iter().map(|c| c.to_ascii_uppercase()).collect(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove closure as shown: `char::to_ascii_uppercase` + | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_ascii_uppercase` -error: redundant closure found - --> $DIR/eta.rs:172:27 +error: redundant closure + --> $DIR/eta.rs:187:27 | LL | let a = Some(1u8).map(|a| foo_ptr(a)); - | ^^^^^^^^^^^^^^ help: remove closure as shown: `foo_ptr` + | ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `foo_ptr` -error: redundant closure found - --> $DIR/eta.rs:177:27 +error: redundant closure + --> $DIR/eta.rs:192:27 | LL | let a = Some(1u8).map(|a| closure(a)); - | ^^^^^^^^^^^^^^ help: remove closure as shown: `closure` + | ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `closure` -error: aborting due to 12 previous errors +error: aborting due to 13 previous errors