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Add config flag for reborrows in explicit_iter_loop

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This commit adds a config flag for enforcing explicit into iter lint
for reborrowed values. The config flag, enforce_iter_loop_reborrow, can be
added to clippy.toml files to enable the linting behaviour. By default
the lint is not enabled.
This commit is contained in:
Ben Schofield 2023-08-27 21:45:14 -06:00
parent 8c20739e4d
commit be55a96d80
8 changed files with 68 additions and 56 deletions
Download patch file Download diff file Expand all files Collapse all files

17
clippy_lints/src/loops/explicit_iter_loop.rs
View file

@ -13,8 +13,14 @@ use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMut
use rustc_middle::ty::{self, EarlyBinder, Ty, TypeAndMut};
use rustc_span::sym;
pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, call_expr: &Expr<'_>, msrv: &Msrv) {
let Some((adjust, ty)) = is_ref_iterable(cx, self_arg, call_expr) else {
pub(super) fn check(
cx: &LateContext<'_>,
self_arg: &Expr<'_>,
call_expr: &Expr<'_>,
msrv: &Msrv,
enforce_iter_loop_reborrow: bool,
) {
let Some((adjust, ty)) = is_ref_iterable(cx, self_arg, call_expr, enforce_iter_loop_reborrow) else {
return;
};
if let ty::Array(_, count) = *ty.peel_refs().kind() {
@ -102,6 +108,7 @@ fn is_ref_iterable<'tcx>(
cx: &LateContext<'tcx>,
self_arg: &Expr<'_>,
call_expr: &Expr<'_>,
enforce_iter_loop_reborrow: bool,
) -> Option<(AdjustKind, Ty<'tcx>)> {
let typeck = cx.typeck_results();
if let Some(trait_id) = cx.tcx.get_diagnostic_item(sym::IntoIterator)
@ -142,7 +149,8 @@ fn is_ref_iterable<'tcx>(
{
return Some((AdjustKind::None, self_ty));
}
} else if let ty::Ref(region, ty, Mutability::Mut) = *self_ty.kind()
} else if enforce_iter_loop_reborrow
&& let ty::Ref(region, ty, Mutability::Mut) = *self_ty.kind()
&& let Some(mutbl) = mutbl
{
// Attempt to reborrow the mutable reference
@ -186,7 +194,8 @@ fn is_ref_iterable<'tcx>(
},
..
] => {
if target != self_ty
if enforce_iter_loop_reborrow
&& target != self_ty
&& implements_trait(cx, target, trait_id, &[])
&& let Some(ty) =
make_normalized_projection(cx.tcx, cx.param_env, trait_id, sym!(IntoIter), [target])

10
clippy_lints/src/loops/mod.rs
View file

@ -609,10 +609,14 @@ declare_clippy_lint! {
pub struct Loops {
msrv: Msrv,
enforce_iter_loop_reborrow: bool,
}
impl Loops {
pub fn new(msrv: Msrv) -> Self {
Self { msrv }
pub fn new(msrv: Msrv, enforce_iter_loop_reborrow: bool) -> Self {
Self {
msrv,
enforce_iter_loop_reborrow,
}
}
}
impl_lint_pass!(Loops => [
@ -719,7 +723,7 @@ impl Loops {
if let ExprKind::MethodCall(method, self_arg, [], _) = arg.kind {
match method.ident.as_str() {
"iter" | "iter_mut" => {
explicit_iter_loop::check(cx, self_arg, arg, &self.msrv);
explicit_iter_loop::check(cx, self_arg, arg, &self.msrv, self.enforce_iter_loop_reborrow);
},
"into_iter" => {
explicit_into_iter_loop::check(cx, self_arg, arg);