use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_hir_and_then};
+use clippy_utils::mir::{enclosing_mir, expr_local, local_assignments, used_exactly_once, PossibleBorrowerMap};
use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
use clippy_utils::sugg::has_enclosing_paren;
use clippy_utils::ty::{expr_sig, is_copy, peel_mid_ty_refs, ty_sig, variant_of_res};
};
use rustc_ast::util::parser::{PREC_POSTFIX, PREC_PREFIX};
use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::graph::iterate::{CycleDetector, TriColorDepthFirstSearch};
use rustc_errors::Applicability;
use rustc_hir::intravisit::{walk_ty, Visitor};
use rustc_hir::{
- self as hir, def_id::DefId, BindingAnnotation, Body, BodyId, BorrowKind, Closure, Expr, ExprKind, FnRetTy,
- GenericArg, HirId, ImplItem, ImplItemKind, Item, ItemKind, Local, MatchSource, Mutability, Node, Pat, PatKind,
- Path, QPath, TraitItem, TraitItemKind, TyKind, UnOp,
+ self as hir,
+ def_id::{DefId, LocalDefId},
+ BindingAnnotation, Body, BodyId, BorrowKind, Closure, Expr, ExprKind, FnRetTy, GenericArg, HirId, ImplItem,
+ ImplItemKind, Item, ItemKind, Local, MatchSource, Mutability, Node, Pat, PatKind, Path, QPath, TraitItem,
+ TraitItemKind, TyKind, UnOp,
};
use rustc_index::bit_set::BitSet;
use rustc_infer::infer::TyCtxtInferExt;
use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::mir::{Rvalue, StatementKind};
use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
use rustc_middle::ty::{
- self, subst::Subst, Binder, BoundVariableKind, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
+ self, Binder, BoundVariableKind, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
ProjectionPredicate, Ty, TyCtxt, TypeVisitable, TypeckResults,
};
use rustc_semver::RustcVersion;
use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::{symbol::sym, Span, Symbol, DUMMY_SP};
+use rustc_span::{symbol::sym, Span, Symbol};
use rustc_trait_selection::infer::InferCtxtExt as _;
use rustc_trait_selection::traits::{query::evaluate_obligation::InferCtxtExt as _, Obligation, ObligationCause};
use std::collections::VecDeque;
/// let x = String::new();
/// let y: &str = &x;
/// ```
- #[clippy::version = "1.60.0"]
+ #[clippy::version = "1.64.0"]
pub EXPLICIT_AUTO_DEREF,
complexity,
"dereferencing when the compiler would automatically dereference"
}
-impl_lint_pass!(Dereferencing => [
+impl_lint_pass!(Dereferencing<'_> => [
EXPLICIT_DEREF_METHODS,
NEEDLESS_BORROW,
REF_BINDING_TO_REFERENCE,
]);
#[derive(Default)]
-pub struct Dereferencing {
+pub struct Dereferencing<'tcx> {
state: Option<(State, StateData)>,
// While parsing a `deref` method call in ufcs form, the path to the function is itself an
/// e.g. `m!(x) | Foo::Bar(ref x)`
ref_locals: FxIndexMap<HirId, Option<RefPat>>,
+ /// Stack of (body owner, `PossibleBorrowerMap`) pairs. Used by
+ /// `needless_borrow_impl_arg_position` to determine when a borrowed expression can instead
+ /// be moved.
+ possible_borrowers: Vec<(LocalDefId, PossibleBorrowerMap<'tcx, 'tcx>)>,
+
// `IntoIterator` for arrays requires Rust 1.53.
msrv: Option<RustcVersion>,
}
-impl Dereferencing {
+impl<'tcx> Dereferencing<'tcx> {
#[must_use]
pub fn new(msrv: Option<RustcVersion>) -> Self {
Self {
}
}
+#[derive(Debug)]
struct StateData {
/// Span of the top level expression
span: Span,
position: Position,
}
+#[derive(Debug)]
struct DerefedBorrow {
count: usize,
msg: &'static str,
snip_expr: Option<HirId>,
}
+#[derive(Debug)]
enum State {
// Any number of deref method calls.
DerefMethod {
hir_id: HirId,
}
-impl<'tcx> LateLintPass<'tcx> for Dereferencing {
+impl<'tcx> LateLintPass<'tcx> for Dereferencing<'tcx> {
#[expect(clippy::too_many_lines)]
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
// Skip path expressions from deref calls. e.g. `Deref::deref(e)`
}
let typeck = cx.typeck_results();
- let (kind, sub_expr) = if let Some(x) = try_parse_ref_op(cx.tcx, typeck, expr) {
- x
- } else {
+ let Some((kind, sub_expr)) = try_parse_ref_op(cx.tcx, typeck, expr) else {
// The whole chain of reference operations has been seen
if let Some((state, data)) = self.state.take() {
report(cx, expr, state, data);
match (self.state.take(), kind) {
(None, kind) => {
let expr_ty = typeck.expr_ty(expr);
- let (position, adjustments) = walk_parents(cx, expr, self.msrv);
-
+ let (position, adjustments) = walk_parents(cx, &mut self.possible_borrowers, expr, self.msrv);
match kind {
RefOp::Deref => {
- if let Position::FieldAccess(name) = position
+ if let Position::FieldAccess {
+ name,
+ of_union: false,
+ } = position
&& !ty_contains_field(typeck.expr_ty(sub_expr), name)
{
self.state = Some((
if !is_lint_allowed(cx, EXPLICIT_DEREF_METHODS, expr.hir_id)
&& position.lint_explicit_deref() =>
{
+ let ty_changed_count = usize::from(!deref_method_same_type(expr_ty, typeck.expr_ty(sub_expr)));
self.state = Some((
State::DerefMethod {
- ty_changed_count: if deref_method_same_type(expr_ty, typeck.expr_ty(sub_expr)) {
- 0
- } else {
- 1
- },
+ ty_changed_count,
is_final_ufcs: matches!(expr.kind, ExprKind::Call(..)),
target_mut,
},
(Some((State::DerefedBorrow(state), data)), RefOp::Deref) => {
let position = data.position;
report(cx, expr, State::DerefedBorrow(state), data);
- if let Position::FieldAccess(name) = position
+ if let Position::FieldAccess{name, ..} = position
&& !ty_contains_field(typeck.expr_ty(sub_expr), name)
{
self.state = Some((
}
fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
- if let PatKind::Binding(BindingAnnotation::Ref, id, name, _) = pat.kind {
+ if let PatKind::Binding(BindingAnnotation::REF, id, name, _) = pat.kind {
if let Some(opt_prev_pat) = self.ref_locals.get_mut(&id) {
// This binding id has been seen before. Add this pattern to the list of changes.
if let Some(prev_pat) = opt_prev_pat {
}
fn check_body_post(&mut self, cx: &LateContext<'tcx>, body: &'tcx Body<'_>) {
+ if self.possible_borrowers.last().map_or(false, |&(local_def_id, _)| {
+ local_def_id == cx.tcx.hir().body_owner_def_id(body.id())
+ }) {
+ self.possible_borrowers.pop();
+ }
+
if Some(body.id()) == self.current_body {
for pat in self.ref_locals.drain(..).filter_map(|(_, x)| x) {
let replacements = pat.replacements;
expr: &'tcx Expr<'_>,
) -> Option<(RefOp, &'tcx Expr<'tcx>)> {
let (def_id, arg) = match expr.kind {
- ExprKind::MethodCall(_, [arg], _) => (typeck.type_dependent_def_id(expr.hir_id)?, arg),
+ ExprKind::MethodCall(_, arg, [], _) => (typeck.type_dependent_def_id(expr.hir_id)?, arg),
ExprKind::Call(
Expr {
kind: ExprKind::Path(path),
}
/// The position of an expression relative to it's parent.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
enum Position {
MethodReceiver,
/// The method is defined on a reference type. e.g. `impl Foo for &T`
MethodReceiverRefImpl,
Callee,
ImplArg(HirId),
- FieldAccess(Symbol),
+ FieldAccess {
+ name: Symbol,
+ of_union: bool,
+ }, // union fields cannot be auto borrowed
Postfix,
Deref,
/// Any other location which will trigger auto-deref to a specific time.
}
fn can_auto_borrow(self) -> bool {
- matches!(self, Self::MethodReceiver | Self::FieldAccess(_) | Self::Callee)
+ matches!(
+ self,
+ Self::MethodReceiver | Self::FieldAccess { of_union: false, .. } | Self::Callee
+ )
}
fn lint_explicit_deref(self) -> bool {
Self::MethodReceiver
| Self::MethodReceiverRefImpl
| Self::Callee
- | Self::FieldAccess(_)
+ | Self::FieldAccess { .. }
| Self::Postfix => PREC_POSTFIX,
Self::ImplArg(_) | Self::Deref => PREC_PREFIX,
Self::DerefStable(p, _) | Self::ReborrowStable(p) | Self::Other(p) => p,
#[expect(clippy::too_many_lines)]
fn walk_parents<'tcx>(
cx: &LateContext<'tcx>,
+ possible_borrowers: &mut Vec<(LocalDefId, PossibleBorrowerMap<'tcx, 'tcx>)>,
e: &'tcx Expr<'_>,
msrv: Option<RustcVersion>,
) -> (Position, &'tcx [Adjustment<'tcx>]) {
},
Node::Item(&Item {
kind: ItemKind::Static(..) | ItemKind::Const(..),
- def_id,
+ owner_id,
span,
..
})
| Node::TraitItem(&TraitItem {
kind: TraitItemKind::Const(..),
- def_id,
+ owner_id,
span,
..
})
| Node::ImplItem(&ImplItem {
kind: ImplItemKind::Const(..),
- def_id,
+ owner_id,
span,
..
}) if span.ctxt() == ctxt => {
- let ty = cx.tcx.type_of(def_id);
+ let ty = cx.tcx.type_of(owner_id.def_id);
Some(ty_auto_deref_stability(cx, ty, precedence).position_for_result(cx))
},
Node::Item(&Item {
kind: ItemKind::Fn(..),
- def_id,
+ owner_id,
span,
..
})
| Node::TraitItem(&TraitItem {
kind: TraitItemKind::Fn(..),
- def_id,
+ owner_id,
span,
..
})
| Node::ImplItem(&ImplItem {
kind: ImplItemKind::Fn(..),
- def_id,
+ owner_id,
span,
..
}) if span.ctxt() == ctxt => {
let output = cx
.tcx
- .erase_late_bound_regions(cx.tcx.fn_sig(def_id.to_def_id()).output());
+ .erase_late_bound_regions(cx.tcx.fn_sig(owner_id.to_def_id()).output());
Some(ty_auto_deref_stability(cx, output, precedence).position_for_result(cx))
},
.position(|arg| arg.hir_id == child_id)
.zip(expr_sig(cx, func))
.and_then(|(i, sig)| {
- sig.input_with_hir(i).map(|(hir_ty, ty)| match hir_ty {
- // Type inference for closures can depend on how they're called. Only go by the explicit
- // types here.
- Some(hir_ty) => binding_ty_auto_deref_stability(cx, hir_ty, precedence, ty.bound_vars()),
- None => {
- if let ty::Param(param_ty) = ty.skip_binder().kind() {
- needless_borrow_impl_arg_position(cx, parent, i, *param_ty, e, precedence, msrv)
- } else {
- ty_auto_deref_stability(cx, cx.tcx.erase_late_bound_regions(ty), precedence)
- .position_for_arg()
- }
- },
+ sig.input_with_hir(i).map(|(hir_ty, ty)| {
+ match hir_ty {
+ // Type inference for closures can depend on how they're called. Only go by the explicit
+ // types here.
+ Some(hir_ty) => {
+ binding_ty_auto_deref_stability(cx, hir_ty, precedence, ty.bound_vars())
+ },
+ None => {
+ // `e.hir_id == child_id` for https://github.com/rust-lang/rust-clippy/issues/9739
+ // `!call_is_qualified(func)` for https://github.com/rust-lang/rust-clippy/issues/9782
+ if e.hir_id == child_id
+ && !call_is_qualified(func)
+ && let ty::Param(param_ty) = ty.skip_binder().kind()
+ {
+ needless_borrow_impl_arg_position(
+ cx,
+ possible_borrowers,
+ parent,
+ i,
+ *param_ty,
+ e,
+ precedence,
+ msrv,
+ )
+ } else {
+ ty_auto_deref_stability(cx, cx.tcx.erase_late_bound_regions(ty), precedence)
+ .position_for_arg()
+ }
+ },
+ }
})
}),
- ExprKind::MethodCall(_, args, _) => {
+ ExprKind::MethodCall(method, receiver, args, _) => {
let id = cx.typeck_results().type_dependent_def_id(parent.hir_id).unwrap();
- args.iter().position(|arg| arg.hir_id == child_id).map(|i| {
- if i == 0 {
- // Check for calls to trait methods where the trait is implemented on a reference.
- // Two cases need to be handled:
- // * `self` methods on `&T` will never have auto-borrow
- // * `&self` methods on `&T` can have auto-borrow, but `&self` methods on `T` will take
- // priority.
- if e.hir_id != child_id {
- Position::ReborrowStable(precedence)
- } else if let Some(trait_id) = cx.tcx.trait_of_item(id)
- && let arg_ty = cx.tcx.erase_regions(cx.typeck_results().expr_ty_adjusted(e))
- && let ty::Ref(_, sub_ty, _) = *arg_ty.kind()
- && let subs = match cx
- .typeck_results()
- .node_substs_opt(parent.hir_id)
- .and_then(|subs| subs.get(1..))
- {
- Some(subs) => cx.tcx.mk_substs(subs.iter().copied()),
- None => cx.tcx.mk_substs(std::iter::empty::<ty::subst::GenericArg<'_>>()),
- } && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
- // Trait methods taking `&self`
- sub_ty
- } else {
- // Trait methods taking `self`
- arg_ty
- } && impl_ty.is_ref()
- && cx.tcx.infer_ctxt().enter(|infcx|
- infcx
- .type_implements_trait(trait_id, impl_ty, subs, cx.param_env)
- .must_apply_modulo_regions()
- )
- {
- Position::MethodReceiverRefImpl
+ if receiver.hir_id == child_id {
+ // Check for calls to trait methods where the trait is implemented on a reference.
+ // Two cases need to be handled:
+ // * `self` methods on `&T` will never have auto-borrow
+ // * `&self` methods on `&T` can have auto-borrow, but `&self` methods on `T` will take
+ // priority.
+ if e.hir_id != child_id {
+ return Some(Position::ReborrowStable(precedence))
+ } else if let Some(trait_id) = cx.tcx.trait_of_item(id)
+ && let arg_ty = cx.tcx.erase_regions(cx.typeck_results().expr_ty_adjusted(e))
+ && let ty::Ref(_, sub_ty, _) = *arg_ty.kind()
+ && let subs = cx
+ .typeck_results()
+ .node_substs_opt(parent.hir_id).map(|subs| &subs[1..]).unwrap_or_default()
+ && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
+ // Trait methods taking `&self`
+ sub_ty
} else {
- Position::MethodReceiver
- }
+ // Trait methods taking `self`
+ arg_ty
+ } && impl_ty.is_ref()
+ && let infcx = cx.tcx.infer_ctxt().build()
+ && infcx
+ .type_implements_trait(trait_id, [impl_ty.into()].into_iter().chain(subs.iter().copied()), cx.param_env)
+ .must_apply_modulo_regions()
+ {
+ return Some(Position::MethodReceiverRefImpl)
+ }
+ return Some(Position::MethodReceiver);
+ }
+ args.iter().position(|arg| arg.hir_id == child_id).map(|i| {
+ let ty = cx.tcx.fn_sig(id).skip_binder().inputs()[i + 1];
+ // `e.hir_id == child_id` for https://github.com/rust-lang/rust-clippy/issues/9739
+ // `method.args.is_none()` for https://github.com/rust-lang/rust-clippy/issues/9782
+ if e.hir_id == child_id && method.args.is_none() && let ty::Param(param_ty) = ty.kind() {
+ needless_borrow_impl_arg_position(
+ cx,
+ possible_borrowers,
+ parent,
+ i + 1,
+ *param_ty,
+ e,
+ precedence,
+ msrv,
+ )
} else {
- let ty = cx.tcx.fn_sig(id).skip_binder().inputs()[i];
- if let ty::Param(param_ty) = ty.kind() {
- needless_borrow_impl_arg_position(cx, parent, i, *param_ty, e, precedence, msrv)
- } else {
- ty_auto_deref_stability(
- cx,
- cx.tcx.erase_late_bound_regions(cx.tcx.fn_sig(id).input(i)),
- precedence,
- )
- .position_for_arg()
- }
+ ty_auto_deref_stability(
+ cx,
+ cx.tcx.erase_late_bound_regions(cx.tcx.fn_sig(id).input(i + 1)),
+ precedence,
+ )
+ .position_for_arg()
}
})
},
- ExprKind::Field(child, name) if child.hir_id == e.hir_id => Some(Position::FieldAccess(name.name)),
+ ExprKind::Field(child, name) if child.hir_id == e.hir_id => Some(Position::FieldAccess {
+ name: name.name,
+ of_union: is_union(cx.typeck_results(), child),
+ }),
ExprKind::Unary(UnOp::Deref, child) if child.hir_id == e.hir_id => Some(Position::Deref),
ExprKind::Match(child, _, MatchSource::TryDesugar | MatchSource::AwaitDesugar)
| ExprKind::Index(child, _)
(position, adjustments)
}
+fn is_union<'tcx>(typeck: &'tcx TypeckResults<'_>, path_expr: &'tcx Expr<'_>) -> bool {
+ typeck
+ .expr_ty_adjusted(path_expr)
+ .ty_adt_def()
+ .map_or(false, rustc_middle::ty::AdtDef::is_union)
+}
+
fn closure_result_position<'tcx>(
cx: &LateContext<'tcx>,
closure: &'tcx Closure<'_>,
cx.typeck_results().node_type(ty.ty.hir_id),
binder_args,
))
- .is_sized(cx.tcx.at(DUMMY_SP), cx.param_env.without_caller_bounds()),
+ .is_sized(cx.tcx, cx.param_env.without_caller_bounds()),
)
}
},
cx.typeck_results().node_type(ty.ty.hir_id),
binder_args,
))
- .is_sized(cx.tcx.at(DUMMY_SP), cx.param_env.without_caller_bounds()),
+ .is_sized(cx.tcx, cx.param_env.without_caller_bounds()),
),
TyKind::OpaqueDef(..) | TyKind::Infer | TyKind::Typeof(..) | TyKind::TraitObject(..) | TyKind::Err => {
Position::ReborrowStable(precedence)
v.0
}
+fn call_is_qualified(expr: &Expr<'_>) -> bool {
+ if let ExprKind::Path(path) = &expr.kind {
+ match path {
+ QPath::Resolved(_, path) => path.segments.last().map_or(false, |segment| segment.args.is_some()),
+ QPath::TypeRelative(_, segment) => segment.args.is_some(),
+ QPath::LangItem(..) => false,
+ }
+ } else {
+ false
+ }
+}
+
// Checks whether:
// * child is an expression of the form `&e` in an argument position requiring an `impl Trait`
// * `e`'s type implements `Trait` and is copyable
// If the conditions are met, returns `Some(Position::ImplArg(..))`; otherwise, returns `None`.
// The "is copyable" condition is to avoid the case where removing the `&` means `e` would have to
// be moved, but it cannot be.
+#[expect(clippy::too_many_arguments, clippy::too_many_lines)]
fn needless_borrow_impl_arg_position<'tcx>(
cx: &LateContext<'tcx>,
+ possible_borrowers: &mut Vec<(LocalDefId, PossibleBorrowerMap<'tcx, 'tcx>)>,
parent: &Expr<'tcx>,
arg_index: usize,
param_ty: ParamTy,
return Position::Other(precedence);
}
+ // See:
+ // - https://github.com/rust-lang/rust-clippy/pull/9674#issuecomment-1289294201
+ // - https://github.com/rust-lang/rust-clippy/pull/9674#issuecomment-1292225232
+ if projection_predicates
+ .iter()
+ .any(|projection_predicate| is_mixed_projection_predicate(cx, callee_def_id, projection_predicate))
+ {
+ return Position::Other(precedence);
+ }
+
// `substs_with_referent_ty` can be constructed outside of `check_referent` because the same
// elements are modified each time `check_referent` is called.
let mut substs_with_referent_ty = substs_with_expr_ty.to_vec();
- let mut check_referent = |referent| {
+ let mut check_reference_and_referent = |reference, referent| {
let referent_ty = cx.typeck_results().expr_ty(referent);
- if !is_copy(cx, referent_ty) {
+ if !is_copy(cx, referent_ty)
+ && (referent_ty.has_significant_drop(cx.tcx, cx.param_env)
+ || !referent_used_exactly_once(cx, possible_borrowers, reference))
+ {
return false;
}
}
let predicate = EarlyBinder(predicate).subst(cx.tcx, &substs_with_referent_ty);
- let obligation = Obligation::new(ObligationCause::dummy(), cx.param_env, predicate);
- cx.tcx
- .infer_ctxt()
- .enter(|infcx| infcx.predicate_must_hold_modulo_regions(&obligation))
+ let obligation = Obligation::new(cx.tcx, ObligationCause::dummy(), cx.param_env, predicate);
+ let infcx = cx.tcx.infer_ctxt().build();
+ infcx.predicate_must_hold_modulo_regions(&obligation)
})
};
let mut needless_borrow = false;
while let ExprKind::AddrOf(_, _, referent) = expr.kind {
- if !check_referent(referent) {
+ if !check_reference_and_referent(expr, referent) {
break;
}
expr = referent;
})
}
+fn is_mixed_projection_predicate<'tcx>(
+ cx: &LateContext<'tcx>,
+ callee_def_id: DefId,
+ projection_predicate: &ProjectionPredicate<'tcx>,
+) -> bool {
+ let generics = cx.tcx.generics_of(callee_def_id);
+ // The predicate requires the projected type to equal a type parameter from the parent context.
+ if let Some(term_ty) = projection_predicate.term.ty()
+ && let ty::Param(term_param_ty) = term_ty.kind()
+ && (term_param_ty.index as usize) < generics.parent_count
+ {
+ // The inner-most self type is a type parameter from the current function.
+ let mut projection_ty = projection_predicate.projection_ty;
+ loop {
+ match projection_ty.self_ty().kind() {
+ ty::Projection(inner_projection_ty) => {
+ projection_ty = *inner_projection_ty;
+ }
+ ty::Param(param_ty) => {
+ return (param_ty.index as usize) >= generics.parent_count;
+ }
+ _ => {
+ return false;
+ }
+ }
+ }
+ } else {
+ false
+ }
+}
+
+fn referent_used_exactly_once<'tcx>(
+ cx: &LateContext<'tcx>,
+ possible_borrowers: &mut Vec<(LocalDefId, PossibleBorrowerMap<'tcx, 'tcx>)>,
+ reference: &Expr<'tcx>,
+) -> bool {
+ let mir = enclosing_mir(cx.tcx, reference.hir_id);
+ if let Some(local) = expr_local(cx.tcx, reference)
+ && let [location] = *local_assignments(mir, local).as_slice()
+ && let Some(statement) = mir.basic_blocks[location.block].statements.get(location.statement_index)
+ && let StatementKind::Assign(box (_, Rvalue::Ref(_, _, place))) = statement.kind
+ && !place.has_deref()
+ // Ensure not in a loop (https://github.com/rust-lang/rust-clippy/issues/9710)
+ && TriColorDepthFirstSearch::new(&mir.basic_blocks).run_from(location.block, &mut CycleDetector).is_none()
+ {
+ let body_owner_local_def_id = cx.tcx.hir().enclosing_body_owner(reference.hir_id);
+ if possible_borrowers
+ .last()
+ .map_or(true, |&(local_def_id, _)| local_def_id != body_owner_local_def_id)
+ {
+ possible_borrowers.push((body_owner_local_def_id, PossibleBorrowerMap::new(cx, mir)));
+ }
+ let possible_borrower = &mut possible_borrowers.last_mut().unwrap().1;
+ // If `only_borrowers` were used here, the `copyable_iterator::warn` test would fail. The reason is
+ // that `PossibleBorrowerVisitor::visit_terminator` considers `place.local` a possible borrower of
+ // itself. See the comment in that method for an explanation as to why.
+ possible_borrower.bounded_borrowers(&[local], &[local, place.local], place.local, location)
+ && used_exactly_once(mir, place.local).unwrap_or(false)
+ } else {
+ false
+ }
+}
+
// Iteratively replaces `param_ty` with `new_ty` in `substs`, and similarly for each resulting
// projected type that is a type parameter. Returns `false` if replacing the types would have an
// effect on the function signature beyond substituting `new_ty` for `param_ty`.
let item_def_id = projection_predicate.projection_ty.item_def_id;
let assoc_item = cx.tcx.associated_item(item_def_id);
let projection = cx.tcx
- .mk_projection(assoc_item.def_id, cx.tcx.mk_substs_trait(new_ty, &[]));
+ .mk_projection(assoc_item.def_id, cx.tcx.mk_substs_trait(new_ty, []));
if let Ok(projected_ty) = cx.tcx.try_normalize_erasing_regions(cx.param_env, projection)
&& substs[term_param_ty.index as usize] != ty::GenericArg::from(projected_ty)
fn position_for_result(self, cx: &LateContext<'tcx>) -> Position {
match (self.position, self.ty) {
(Position::ReborrowStable(precedence), Some(ty)) => {
- Position::DerefStable(precedence, ty.is_sized(cx.tcx.at(DUMMY_SP), cx.param_env))
+ Position::DerefStable(precedence, ty.is_sized(cx.tcx, cx.param_env))
},
(position, _) => position,
}
continue;
},
ty::Param(_) => TyPosition::new_deref_stable_for_result(precedence, ty),
+ ty::Projection(_) if ty.has_non_region_param() => TyPosition::new_deref_stable_for_result(precedence, ty),
ty::Infer(_) | ty::Error(_) | ty::Bound(..) | ty::Opaque(..) | ty::Placeholder(_) | ty::Dynamic(..) => {
Position::ReborrowStable(precedence).into()
},
ty::Adt(..) if ty.has_placeholders() || ty.has_opaque_types() => {
Position::ReborrowStable(precedence).into()
},
- ty::Adt(_, substs) if substs.has_param_types_or_consts() => {
+ ty::Adt(_, substs) if substs.has_non_region_param() => {
TyPosition::new_deref_stable_for_result(precedence, ty)
},
ty::Bool
| ty::Closure(..)
| ty::Never
| ty::Tuple(_)
- | ty::Projection(_) => Position::DerefStable(
- precedence,
- ty.is_sized(cx.tcx.at(DUMMY_SP), cx.param_env.without_caller_bounds()),
- )
- .into(),
+ | ty::Projection(_) => {
+ Position::DerefStable(precedence, ty.is_sized(cx.tcx, cx.param_env.without_caller_bounds())).into()
+ },
};
}
}
};
let expr_str = if !expr_is_macro_call && is_final_ufcs && expr.precedence().order() < PREC_PREFIX {
- format!("({})", expr_str)
+ format!("({expr_str})")
} else {
expr_str.into_owned()
};
Mutability::Mut => "explicit `deref_mut` method call",
},
"try this",
- format!("{}{}{}", addr_of_str, deref_str, expr_str),
+ format!("{addr_of_str}{deref_str}{expr_str}"),
app,
);
},
&& !has_enclosing_paren(&snip)
&& (expr.precedence().order() < data.position.precedence() || calls_field)
{
- format!("({})", snip)
+ format!("({snip})")
} else {
snip.into()
};
let (snip, snip_is_macro) = snippet_with_context(cx, expr.span, data.span.ctxt(), "..", &mut app);
let sugg =
if !snip_is_macro && expr.precedence().order() < precedence && !has_enclosing_paren(&snip) {
- format!("{}({})", prefix, snip)
+ format!("{prefix}({snip})")
} else {
- format!("{}{}", prefix, snip)
+ format!("{prefix}{snip}")
};
diag.span_suggestion(data.span, "try this", sugg, app);
},
}
}
-impl Dereferencing {
- fn check_local_usage<'tcx>(&mut self, cx: &LateContext<'tcx>, e: &Expr<'tcx>, local: HirId) {
+impl<'tcx> Dereferencing<'tcx> {
+ fn check_local_usage(&mut self, cx: &LateContext<'tcx>, e: &Expr<'tcx>, local: HirId) {
if let Some(outer_pat) = self.ref_locals.get_mut(&local) {
if let Some(pat) = outer_pat {
// Check for auto-deref
} else {
pat.always_deref = false;
let snip = snippet_with_context(cx, e.span, parent.span.ctxt(), "..", &mut pat.app).0;
- pat.replacements.push((e.span, format!("&{}", snip)));
+ pat.replacements.push((e.span, format!("&{snip}")));
}
},
_ if !e.span.from_expansion() => {
// Double reference might be needed at this point.
pat.always_deref = false;
let snip = snippet_with_applicability(cx, e.span, "..", &mut pat.app);
- pat.replacements.push((e.span, format!("&{}", snip)));
+ pat.replacements.push((e.span, format!("&{snip}")));
},
// Edge case for macros. The span of the identifier will usually match the context of the
// binding, but not if the identifier was created in a macro. e.g. `concat_idents` and proc
projects / rust.git / blobdiff