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Reborrow mutable references in explicit_iter_loop

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This commit is contained in:
Jason Newcomb 2023-02-27 13:53:53 -05:00
parent 482baf2bcc
commit 949712c90a
24 changed files with 159 additions and 58 deletions
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4
clippy_lints/src/attrs.rs
View file

@ -808,7 +808,7 @@ fn check_deprecated_cfg_attr(cx: &EarlyContext<'_>, attr: &Attribute, msrv: &Msr
}
fn check_nested_cfg(cx: &EarlyContext<'_>, items: &[NestedMetaItem]) {
for item in items.iter() {
for item in items {
if let NestedMetaItem::MetaItem(meta) = item {
if !meta.has_name(sym::any) && !meta.has_name(sym::all) {
continue;
@ -842,7 +842,7 @@ fn check_nested_cfg(cx: &EarlyContext<'_>, items: &[NestedMetaItem]) {
}
fn check_nested_misused_cfg(cx: &EarlyContext<'_>, items: &[NestedMetaItem]) {
for item in items.iter() {
for item in items {
if let NestedMetaItem::MetaItem(meta) = item {
if meta.has_name(sym!(features)) && let Some(val) = meta.value_str() {
span_lint_and_sugg(

2
clippy_lints/src/default_numeric_fallback.rs
View file

@ -161,7 +161,7 @@ impl<'a, 'tcx> Visitor<'tcx> for NumericFallbackVisitor<'a, 'tcx> {
let fields_def = &variant.fields;
// Push field type then visit each field expr.
for field in fields.iter() {
for field in *fields {
let bound =
fields_def
.iter()

2
clippy_lints/src/lifetimes.rs
View file

@ -562,7 +562,7 @@ fn has_where_lifetimes<'tcx>(cx: &LateContext<'tcx>, generics: &'tcx Generics<'_
// if the bounds define new lifetimes, they are fine to occur
let allowed_lts = allowed_lts_from(pred.bound_generic_params);
// now walk the bounds
for bound in pred.bounds.iter() {
for bound in pred.bounds {
walk_param_bound(&mut visitor, bound);
}
// and check that all lifetimes are allowed

2
clippy_lints/src/loops/explicit_into_iter_loop.rs
View file

@ -84,7 +84,7 @@ pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, call_expr: &Expr<
"it is more concise to loop over containers instead of using explicit \
iteration methods",
"to write this more concisely, try",
format!("{}{}", adjust.display(), object.to_string()),
format!("{}{object}", adjust.display()),
applicability,
);
}

77
clippy_lints/src/loops/explicit_iter_loop.rs
View file

@ -33,14 +33,6 @@ pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, call_expr: &Expr<
let mut applicability = Applicability::MachineApplicable;
let object = snippet_with_applicability(cx, self_arg.span, "_", &mut applicability);
let prefix = match adjust {
AdjustKind::None => "",
AdjustKind::Borrow => "&",
AdjustKind::BorrowMut => "&mut ",
AdjustKind::Deref => "*",
AdjustKind::Reborrow => "&*",
AdjustKind::ReborrowMut => "&mut *",
};
span_lint_and_sugg(
cx,
EXPLICIT_ITER_LOOP,
@ -48,11 +40,12 @@ pub(super) fn check(cx: &LateContext<'_>, self_arg: &Expr<'_>, call_expr: &Expr<
"it is more concise to loop over references to containers instead of using explicit \
iteration methods",
"to write this more concisely, try",
format!("{prefix}{object}"),
format!("{}{object}", adjust.display()),
applicability,
);
}
#[derive(Clone, Copy)]
enum AdjustKind {
None,
Borrow,
@ -76,16 +69,35 @@ impl AdjustKind {
}
}
fn reborrow(mutbl: AutoBorrowMutability) -> Self {
fn reborrow(mutbl: Mutability) -> Self {
match mutbl {
Mutability::Not => Self::Reborrow,
Mutability::Mut => Self::ReborrowMut,
}
}
fn auto_reborrow(mutbl: AutoBorrowMutability) -> Self {
match mutbl {
AutoBorrowMutability::Not => Self::Reborrow,
AutoBorrowMutability::Mut { .. } => Self::ReborrowMut,
}
}
fn display(self) -> &'static str {
match self {
Self::None => "",
Self::Borrow => "&",
Self::BorrowMut => "&mut ",
Self::Deref => "*",
Self::Reborrow => "&*",
Self::ReborrowMut => "&mut *",
}
}
}
/// Checks if an `iter` or `iter_mut` call returns `IntoIterator::IntoIter`. Returns how the
/// argument needs to be adjusted.
#[expect(clippy::too_many_lines)]
fn is_ref_iterable<'tcx>(
cx: &LateContext<'tcx>,
self_arg: &Expr<'_>,
@ -108,27 +120,50 @@ fn is_ref_iterable<'tcx>(
let self_is_copy = is_copy(cx, self_ty);
if adjustments.is_empty() && self_is_copy {
// Exact type match, already checked earlier
return Some((AdjustKind::None, self_ty));
}
let res_ty = cx.tcx.erase_regions(EarlyBinder::bind(req_res_ty).subst(cx.tcx, typeck.node_substs(call_expr.hir_id)));
if !adjustments.is_empty() && self_is_copy {
if implements_trait(cx, self_ty, trait_id, &[])
&& let Some(ty) = make_normalized_projection(cx.tcx, cx.param_env, trait_id, sym!(IntoIter), [self_ty])
&& ty == res_ty
{
return Some((AdjustKind::None, self_ty));
}
}
let res_ty = cx.tcx.erase_regions(EarlyBinder::bind(req_res_ty)
.subst(cx.tcx, typeck.node_substs(call_expr.hir_id)));
let mutbl = if let ty::Ref(_, _, mutbl) = *req_self_ty.kind() {
Some(mutbl)
} else {
None
};
if !adjustments.is_empty() {
if self_is_copy {
// Using by value won't consume anything
if implements_trait(cx, self_ty, trait_id, &[])
&& let Some(ty) =
make_normalized_projection(cx.tcx, cx.param_env, trait_id, sym!(IntoIter), [self_ty])
&& ty == res_ty
{
return Some((AdjustKind::None, self_ty));
}
} else if let ty::Ref(region, ty, Mutability::Mut) = *self_ty.kind()
&& let Some(mutbl) = mutbl
{
// Attempt to reborrow the mutable reference
let self_ty = if mutbl.is_mut() {
self_ty
} else {
cx.tcx.mk_ref(region, TypeAndMut { ty, mutbl })
};
if implements_trait(cx, self_ty, trait_id, &[])
&& let Some(ty) =
make_normalized_projection(cx.tcx, cx.param_env, trait_id, sym!(IntoIter), [self_ty])
&& ty == res_ty
{
return Some((AdjustKind::reborrow(mutbl), self_ty));
}
}
}
if let Some(mutbl) = mutbl
&& !self_ty.is_ref()
{
// Attempt to borrow
let self_ty = cx.tcx.mk_ref(cx.tcx.lifetimes.re_erased, TypeAndMut {
ty: self_ty,
mutbl,
@ -157,7 +192,7 @@ fn is_ref_iterable<'tcx>(
make_normalized_projection(cx.tcx, cx.param_env, trait_id, sym!(IntoIter), [target])
&& ty == res_ty
{
Some((AdjustKind::reborrow(mutbl), target))
Some((AdjustKind::auto_reborrow(mutbl), target))
} else {
None
}

2
clippy_lints/src/loops/mod.rs
View file

@ -687,6 +687,8 @@ impl<'tcx> LateLintPass<'tcx> for Loops {
manual_while_let_some::check(cx, condition, body, span);
}
}
extract_msrv_attr!(LateContext);
}
impl Loops {

2
clippy_lints/src/loops/same_item_push.rs
View file

@ -148,7 +148,7 @@ impl<'a, 'tcx> Visitor<'tcx> for SameItemPushVisitor<'a, 'tcx> {
}
fn visit_block(&mut self, b: &'tcx Block<'_>) {
for stmt in b.stmts.iter() {
for stmt in b.stmts {
self.visit_stmt(stmt);
}
}

2
clippy_lints/src/macro_use.rs
View file

@ -101,7 +101,7 @@ impl<'tcx> LateLintPass<'tcx> for MacroUseImports {
});
if !id.is_local();
then {
for kid in cx.tcx.module_children(id).iter() {
for kid in cx.tcx.module_children(id) {
if let Res::Def(DefKind::Macro(_mac_type), mac_id) = kid.res {
let span = mac_attr.span;
let def_path = cx.tcx.def_path_str(mac_id);

2
clippy_lints/src/matches/match_wild_err_arm.rs
View file

@ -25,7 +25,7 @@ pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'tcx>, arms: &[Arm<'
let mut ident_bind_name = kw::Underscore;
if !matching_wild {
// Looking for unused bindings (i.e.: `_e`)
for pat in inner.iter() {
for pat in inner {
if let PatKind::Binding(_, id, ident, None) = pat.kind {
if ident.as_str().starts_with('_') && !is_local_used(cx, arm.body, id) {
ident_bind_name = ident.name;

2
clippy_lints/src/matches/significant_drop_in_scrutinee.rs
View file

@ -140,7 +140,7 @@ impl<'a, 'tcx> SigDropChecker<'a, 'tcx> {
}
}
for generic_arg in b.iter() {
for generic_arg in *b {
if let GenericArgKind::Type(ty) = generic_arg.unpack() {
if self.has_sig_drop_attr(cx, ty) {
return true;

2
clippy_lints/src/matches/try_err.rs
View file

@ -81,7 +81,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, scrutine
/// Finds function return type by examining return expressions in match arms.
fn find_return_type<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx ExprKind<'_>) -> Option<Ty<'tcx>> {
if let ExprKind::Match(_, arms, MatchSource::TryDesugar) = expr {
for arm in arms.iter() {
for arm in *arms {
if let ExprKind::Ret(Some(ret)) = arm.body.kind {
return Some(cx.typeck_results().expr_ty(ret));
}

2
clippy_lints/src/misc_early/mixed_case_hex_literals.rs
View file

@ -13,7 +13,7 @@ pub(super) fn check(cx: &EarlyContext<'_>, lit_span: Span, suffix: &str, lit_sni
return;
}
let mut seen = (false, false);
for ch in lit_snip.as_bytes()[2..=maybe_last_sep_idx].iter() {
for ch in &lit_snip.as_bytes()[2..=maybe_last_sep_idx] {
match ch {
b'a'..=b'f' => seen.0 = true,
b'A'..=b'F' => seen.1 = true,

2
clippy_lints/src/mismatching_type_param_order.rs
View file

@ -59,7 +59,7 @@ impl<'tcx> LateLintPass<'tcx> for TypeParamMismatch {
then {
// get the name and span of the generic parameters in the Impl
let mut impl_params = Vec::new();
for p in generic_args.args.iter() {
for p in generic_args.args {
match p {
GenericArg::Type(Ty {kind: TyKind::Path(QPath::Resolved(_, path)), ..}) =>
impl_params.push((path.segments[0].ident.to_string(), path.span)),

2
clippy_lints/src/returns.rs
View file

@ -292,7 +292,7 @@ fn check_final_expr<'tcx>(
// (except for unit type functions) so we don't match it
ExprKind::Match(_, arms, MatchSource::Normal) => {
let match_ty = cx.typeck_results().expr_ty(peeled_drop_expr);
for arm in arms.iter() {
for arm in *arms {
check_final_expr(cx, arm.body, semi_spans.clone(), RetReplacement::Unit, Some(match_ty));
}
},

2
clippy_lints/src/significant_drop_tightening.rs
View file

@ -333,7 +333,7 @@ impl<'cx, 'sdt, 'tcx> SigDropChecker<'cx, 'sdt, 'tcx> {
return true;
}
}
for generic_arg in b.iter() {
for generic_arg in *b {
if let GenericArgKind::Type(ty) = generic_arg.unpack() {
if self.has_sig_drop_attr(ty) {
return true;

4
clippy_lints/src/trait_bounds.rs
View file

@ -139,7 +139,7 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
) = cx.tcx.hir().get_if_local(*def_id);
then {
if self_bounds_map.is_empty() {
for bound in self_bounds.iter() {
for bound in *self_bounds {
let Some((self_res, self_segments, _)) = get_trait_info_from_bound(bound) else { continue };
self_bounds_map.insert(self_res, self_segments);
}
@ -184,7 +184,7 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
// Iterate the bounds and add them to our seen hash
// If we haven't yet seen it, add it to the fixed traits
for bound in bounds.iter() {
for bound in bounds {
let Some(def_id) = bound.trait_ref.trait_def_id() else { continue; };
let new_trait = seen_def_ids.insert(def_id);

2
clippy_lints/src/utils/internal_lints/interning_defined_symbol.rs
View file

@ -75,7 +75,7 @@ impl<'tcx> LateLintPass<'tcx> for InterningDefinedSymbol {
for &module in &[&paths::KW_MODULE, &paths::SYM_MODULE] {
for def_id in def_path_def_ids(cx, module) {
for item in cx.tcx.module_children(def_id).iter() {
for item in cx.tcx.module_children(def_id) {
if_chain! {
if let Res::Def(DefKind::Const, item_def_id) = item.res;
let ty = cx.tcx.type_of(item_def_id).subst_identity();

4
clippy_utils/src/qualify_min_const_fn.rs
View file

@ -61,7 +61,7 @@ pub fn is_min_const_fn<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, msrv: &Msrv)
body.local_decls.iter().next().unwrap().source_info.span,
)?;
for bb in body.basic_blocks.iter() {
for bb in &*body.basic_blocks {
check_terminator(tcx, body, bb.terminator(), msrv)?;
for stmt in &bb.statements {
check_statement(tcx, body, def_id, stmt)?;
@ -89,7 +89,7 @@ fn check_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, span: Span) -> McfResult {
return Err((span, "function pointers in const fn are unstable".into()));
},
ty::Dynamic(preds, _, _) => {
for pred in preds.iter() {
for pred in *preds {
match pred.skip_binder() {
ty::ExistentialPredicate::AutoTrait(_) | ty::ExistentialPredicate::Projection(_) => {
return Err((

2
clippy_utils/src/ty.rs
View file

@ -277,7 +277,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
false
},
ty::Dynamic(binder, _, _) => {
for predicate in binder.iter() {
for predicate in *binder {
if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
if cx.tcx.has_attr(trait_ref.def_id, sym::must_use) {
return true;

2
clippy_utils/src/usage.rs
View file

@ -82,7 +82,7 @@ pub struct ParamBindingIdCollector {
impl<'tcx> ParamBindingIdCollector {
fn collect_binding_hir_ids(body: &'tcx hir::Body<'tcx>) -> Vec<hir::HirId> {
let mut hir_ids: Vec<hir::HirId> = Vec::new();
for param in body.params.iter() {
for param in body.params {
let mut finder = ParamBindingIdCollector {
binding_hir_ids: Vec::new(),
};

2
lintcheck/src/main.rs
View file

@ -474,7 +474,7 @@ fn read_crates(toml_path: &Path) -> (Vec<CrateSource>, RecursiveOptions) {
});
} else if let Some(ref versions) = tk.versions {
// if we have multiple versions, save each one
for ver in versions.iter() {
for ver in versions {
crate_sources.push(CrateSource::CratesIo {
name: tk.name.clone(),
version: ver.to_string(),

14
tests/ui/explicit_iter_loop.fixed
View file

@ -17,6 +17,13 @@ fn main() {
for _ in &vec {}
for _ in &mut vec {}
let rvec = &vec;
for _ in rvec {}
let rmvec = &mut vec;
for _ in &*rmvec {}
for _ in &mut *rmvec {}
for _ in &vec {} // these are fine
for _ in &mut vec {} // these are fine
@ -29,9 +36,13 @@ fn main() {
let ll: LinkedList<()> = LinkedList::new();
for _ in &ll {}
let rll = &ll;
for _ in rll {}
let vd: VecDeque<()> = VecDeque::new();
for _ in &vd {}
let rvd = &vd;
for _ in rvd {}
let bh: BinaryHeap<()> = BinaryHeap::new();
for _ in &bh {}
@ -137,4 +148,7 @@ fn main() {
let mut x = CustomType;
for _ in &x {}
for _ in &mut x {}
let r = &x;
for _ in r {}
}

14
tests/ui/explicit_iter_loop.rs
View file

@ -17,6 +17,13 @@ fn main() {
for _ in vec.iter() {}
for _ in vec.iter_mut() {}
let rvec = &vec;
for _ in rvec.iter() {}
let rmvec = &mut vec;
for _ in rmvec.iter() {}
for _ in rmvec.iter_mut() {}
for _ in &vec {} // these are fine
for _ in &mut vec {} // these are fine
@ -29,9 +36,13 @@ fn main() {
let ll: LinkedList<()> = LinkedList::new();
for _ in ll.iter() {}
let rll = &ll;
for _ in rll.iter() {}
let vd: VecDeque<()> = VecDeque::new();
for _ in vd.iter() {}
let rvd = &vd;
for _ in rvd.iter() {}
let bh: BinaryHeap<()> = BinaryHeap::new();
for _ in bh.iter() {}
@ -137,4 +148,7 @@ fn main() {
let mut x = CustomType;
for _ in x.iter() {}
for _ in x.iter_mut() {}
let r = &x;
for _ in r.iter() {}
}

66
tests/ui/explicit_iter_loop.stderr
View file

@ -17,19 +17,37 @@ LL | for _ in vec.iter_mut() {}
| ^^^^^^^^^^^^^^ help: to write this more concisely, try: `&mut vec`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:23:14
--> $DIR/explicit_iter_loop.rs:21:14
|
LL | for _ in rvec.iter() {}
| ^^^^^^^^^^^ help: to write this more concisely, try: `rvec`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:24:14
|
LL | for _ in rmvec.iter() {}
| ^^^^^^^^^^^^ help: to write this more concisely, try: `&*rmvec`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:25:14
|
LL | for _ in rmvec.iter_mut() {}
| ^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `&mut *rmvec`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:30:14
|
LL | for _ in [1, 2, 3].iter() {}
| ^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `&[1, 2, 3]`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:25:14
--> $DIR/explicit_iter_loop.rs:32:14
|
LL | for _ in (&mut [1, 2, 3]).iter() {}
| ^^^^^^^^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `&*(&mut [1, 2, 3])`
error: the method `iter` doesn't need a mutable reference
--> $DIR/explicit_iter_loop.rs:25:14
--> $DIR/explicit_iter_loop.rs:32:14
|
LL | for _ in (&mut [1, 2, 3]).iter() {}
| ^^^^^^^^^^^^^^^^
@ -37,70 +55,88 @@ LL | for _ in (&mut [1, 2, 3]).iter() {}
= note: `-D clippy::unnecessary-mut-passed` implied by `-D warnings`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:27:14
--> $DIR/explicit_iter_loop.rs:34:14
|
LL | for _ in [0; 32].iter() {}
| ^^^^^^^^^^^^^^ help: to write this more concisely, try: `&[0; 32]`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:28:14
--> $DIR/explicit_iter_loop.rs:35:14
|
LL | for _ in [0; 33].iter() {}
| ^^^^^^^^^^^^^^ help: to write this more concisely, try: `&[0; 33]`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:31:14
--> $DIR/explicit_iter_loop.rs:38:14
|
LL | for _ in ll.iter() {}
| ^^^^^^^^^ help: to write this more concisely, try: `&ll`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:34:14
--> $DIR/explicit_iter_loop.rs:40:14
|
LL | for _ in rll.iter() {}
| ^^^^^^^^^^ help: to write this more concisely, try: `rll`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:43:14
|
LL | for _ in vd.iter() {}
| ^^^^^^^^^ help: to write this more concisely, try: `&vd`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:37:14
--> $DIR/explicit_iter_loop.rs:45:14
|
LL | for _ in rvd.iter() {}
| ^^^^^^^^^^ help: to write this more concisely, try: `rvd`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:48:14
|
LL | for _ in bh.iter() {}
| ^^^^^^^^^ help: to write this more concisely, try: `&bh`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:40:14
--> $DIR/explicit_iter_loop.rs:51:14
|
LL | for _ in hm.iter() {}
| ^^^^^^^^^ help: to write this more concisely, try: `&hm`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:43:14
--> $DIR/explicit_iter_loop.rs:54:14
|
LL | for _ in bt.iter() {}
| ^^^^^^^^^ help: to write this more concisely, try: `&bt`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:46:14
--> $DIR/explicit_iter_loop.rs:57:14
|
LL | for _ in hs.iter() {}
| ^^^^^^^^^ help: to write this more concisely, try: `&hs`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:49:14
--> $DIR/explicit_iter_loop.rs:60:14
|
LL | for _ in bs.iter() {}
| ^^^^^^^^^ help: to write this more concisely, try: `&bs`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:138:14
--> $DIR/explicit_iter_loop.rs:149:14
|
LL | for _ in x.iter() {}
| ^^^^^^^^ help: to write this more concisely, try: `&x`
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:139:14
--> $DIR/explicit_iter_loop.rs:150:14
|
LL | for _ in x.iter_mut() {}
| ^^^^^^^^^^^^ help: to write this more concisely, try: `&mut x`
error: aborting due to 16 previous errors
error: it is more concise to loop over references to containers instead of using explicit iteration methods
--> $DIR/explicit_iter_loop.rs:153:14
|
LL | for _ in r.iter() {}
| ^^^^^^^^ help: to write this more concisely, try: `r`
error: aborting due to 22 previous errors