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Auto merge of #11226 - GuillaumeGomez:needless-ref-mut-cfg, r=llogiq

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Needless ref mut cfg

Fixes https://github.com/rust-lang/rust-clippy/issues/11185.

cc `@Centri3`

changelog: Emit note if function is behind a cfg for `NEEDLESS_PASS_BY_REF_MUT` lint.
This commit is contained in:
bors 2023-07-25 19:00:59 +00:00
commit 2153c0fcc8
4 changed files with 71 additions and 27 deletions
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7
clippy_lints/src/needless_pass_by_ref_mut.rs
View File

@ -1,7 +1,7 @@
use super::needless_pass_by_value::requires_exact_signature;
use clippy_utils::diagnostics::span_lint_hir_and_then;
use clippy_utils::source::snippet;
use clippy_utils::{get_parent_node, is_from_proc_macro, is_self};
use clippy_utils::{get_parent_node, inherits_cfg, is_from_proc_macro, is_self};
use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
use rustc_errors::Applicability;
use rustc_hir::intravisit::{walk_qpath, FnKind, Visitor};
@ -192,10 +192,12 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByRefMut<'tcx> {
let show_semver_warning =
self.avoid_breaking_exported_api && cx.effective_visibilities.is_exported(*fn_def_id);
let mut is_cfged = None;
for input in unused {
// If the argument is never used mutably, we emit the warning.
let sp = input.span;
if let rustc_hir::TyKind::Ref(_, inner_ty) = input.kind {
let is_cfged = is_cfged.get_or_insert_with(|| inherits_cfg(cx.tcx, *fn_def_id));
span_lint_hir_and_then(
cx,
NEEDLESS_PASS_BY_REF_MUT,
@ -212,6 +214,9 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByRefMut<'tcx> {
if show_semver_warning {
diag.warn("changing this function will impact semver compatibility");
}
if *is_cfged {
diag.note("this is cfg-gated and may require further changes");
}
},
);
}

11
clippy_utils/src/lib.rs
View File

@ -2451,6 +2451,17 @@ pub fn is_in_cfg_test(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
.any(is_cfg_test)
}
/// Checks if the item of any of its parents has `#[cfg(...)]` attribute applied.
pub fn inherits_cfg(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
let hir = tcx.hir();
tcx.has_attr(def_id, sym::cfg)
|| hir
.parent_iter(hir.local_def_id_to_hir_id(def_id))
.flat_map(|(parent_id, _)| hir.attrs(parent_id))
.any(|attr| attr.has_name(sym::cfg))
}
/// Checks whether item either has `test` attribute applied, or
/// is a module with `test` in its name.
///

36
tests/ui/needless_pass_by_ref_mut.rs
View File

@ -3,8 +3,8 @@
use std::ptr::NonNull;
// Should only warn for `s`.
fn foo(s: &mut Vec<u32>, b: &u32, x: &mut u32) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
*x += *b + s.len() as u32;
}
@ -28,8 +28,8 @@ fn foo5(s: &mut Vec<u32>) {
foo2(s);
}
// Should warn.
fn foo6(s: &mut Vec<u32>) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
non_mut_ref(s);
}
@ -41,13 +41,13 @@ impl Bar {
// Should not warn on `&mut self`.
fn bar(&mut self) {}
// Should warn about `vec`
fn mushroom(&self, vec: &mut Vec<i32>) -> usize {
//~^ ERROR: this argument is a mutable reference, but not used mutably
vec.len()
}
// Should warn about `vec` (and not `self`).
fn badger(&mut self, vec: &mut Vec<i32>) -> usize {
//~^ ERROR: this argument is a mutable reference, but not used mutably
vec.len()
}
}
@ -123,36 +123,36 @@ async fn f7(x: &mut i32, y: i32, z: &mut i32, a: i32) {
*z += 1;
}
// Should warn.
async fn a1(x: &mut i32) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", x);
}
// Should warn.
async fn a2(x: &mut i32, y: String) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", x);
}
// Should warn.
async fn a3(x: &mut i32, y: String, z: String) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", x);
}
// Should warn.
async fn a4(x: &mut i32, y: i32) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", x);
}
// Should warn.
async fn a5(x: i32, y: &mut i32) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", x);
}
// Should warn.
async fn a6(x: i32, y: &mut i32) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", x);
}
// Should warn.
async fn a7(x: i32, y: i32, z: &mut i32) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", z);
}
// Should warn.
async fn a8(x: i32, a: &mut i32, y: i32, z: &mut i32) {
//~^ ERROR: this argument is a mutable reference, but not used mutably
println!("{:?}", z);
}
@ -184,6 +184,18 @@ fn used_as_path(s: &mut u32) {}
#[expect(clippy::needless_pass_by_ref_mut)]
fn lint_attr(s: &mut u32) {}
#[cfg(not(feature = "a"))]
fn cfg_warn(s: &mut u32) {}
//~^ ERROR: this argument is a mutable reference, but not used mutably
//~| NOTE: this is cfg-gated and may require further changes
#[cfg(not(feature = "a"))]
mod foo {
fn cfg_warn(s: &mut u32) {}
//~^ ERROR: this argument is a mutable reference, but not used mutably
//~| NOTE: this is cfg-gated and may require further changes
}
fn main() {
let mut u = 0;
let mut v = vec![0];

44
tests/ui/needless_pass_by_ref_mut.stderr
View File

@ -1,5 +1,5 @@
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:7:11
--> $DIR/needless_pass_by_ref_mut.rs:6:11
|
LL | fn foo(s: &mut Vec<u32>, b: &u32, x: &mut u32) {
| ^^^^^^^^^^^^^ help: consider changing to: `&Vec<u32>`
@ -7,76 +7,92 @@ LL | fn foo(s: &mut Vec<u32>, b: &u32, x: &mut u32) {
= note: `-D clippy::needless-pass-by-ref-mut` implied by `-D warnings`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:32:12
--> $DIR/needless_pass_by_ref_mut.rs:31:12
|
LL | fn foo6(s: &mut Vec<u32>) {
| ^^^^^^^^^^^^^ help: consider changing to: `&Vec<u32>`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:45:29
--> $DIR/needless_pass_by_ref_mut.rs:44:29
|
LL | fn mushroom(&self, vec: &mut Vec<i32>) -> usize {
| ^^^^^^^^^^^^^ help: consider changing to: `&Vec<i32>`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:50:31
--> $DIR/needless_pass_by_ref_mut.rs:49:31
|
LL | fn badger(&mut self, vec: &mut Vec<i32>) -> usize {
| ^^^^^^^^^^^^^ help: consider changing to: `&Vec<i32>`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:127:16
--> $DIR/needless_pass_by_ref_mut.rs:126:16
|
LL | async fn a1(x: &mut i32) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:131:16
--> $DIR/needless_pass_by_ref_mut.rs:130:16
|
LL | async fn a2(x: &mut i32, y: String) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:135:16
--> $DIR/needless_pass_by_ref_mut.rs:134:16
|
LL | async fn a3(x: &mut i32, y: String, z: String) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:139:16
--> $DIR/needless_pass_by_ref_mut.rs:138:16
|
LL | async fn a4(x: &mut i32, y: i32) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:143:24
--> $DIR/needless_pass_by_ref_mut.rs:142:24
|
LL | async fn a5(x: i32, y: &mut i32) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:147:24
--> $DIR/needless_pass_by_ref_mut.rs:146:24
|
LL | async fn a6(x: i32, y: &mut i32) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:151:32
--> $DIR/needless_pass_by_ref_mut.rs:150:32
|
LL | async fn a7(x: i32, y: i32, z: &mut i32) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:155:24
--> $DIR/needless_pass_by_ref_mut.rs:154:24
|
LL | async fn a8(x: i32, a: &mut i32, y: i32, z: &mut i32) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:155:45
--> $DIR/needless_pass_by_ref_mut.rs:154:45
|
LL | async fn a8(x: i32, a: &mut i32, y: i32, z: &mut i32) {
| ^^^^^^^^ help: consider changing to: `&i32`
error: aborting due to 13 previous errors
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:188:16
|
LL | fn cfg_warn(s: &mut u32) {}
| ^^^^^^^^ help: consider changing to: `&u32`
|
= note: this is cfg-gated and may require further changes
error: this argument is a mutable reference, but not used mutably
--> $DIR/needless_pass_by_ref_mut.rs:194:20
|
LL | fn cfg_warn(s: &mut u32) {}
| ^^^^^^^^ help: consider changing to: `&u32`
|
= note: this is cfg-gated and may require further changes
error: aborting due to 15 previous errors