Try to explain borrow for tail expr temporary drop order change in 2024
This commit is contained in:
Michael Goulet
parent
4a099b29cd
commit
c55eefe8bc
9 changed files with 81 additions and 42 deletions
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@ -213,8 +213,9 @@ borrowck_suggest_create_fresh_reborrow =
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borrowck_suggest_iterate_over_slice =
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consider iterating over a slice of the `{$ty}`'s content to avoid moving into the `for` loop
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borrowck_tail_expr_drop_order = a temporary value will be dropped here before the execution exits the block in Edition 2024, which will raise borrow checking error
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.label = consider using a `let` binding to create a longer lived value; or replacing the `{"{"} .. {"}"}` block with curly brackets `( .. )`; or folding the rest of the expression into the surrounding `unsafe {"{"} .. {"}"}`
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borrowck_tail_expr_drop_order = relative drop order changing in Rust 2024
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.label = this temporary value will be dropped at the end of the block
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.note = consider using a `let` binding to ensure the value will live long enough
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borrowck_ty_no_impl_copy =
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{$is_partial_move ->
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@ -5,7 +5,7 @@
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use std::assert_matches::assert_matches;
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use rustc_errors::{Applicability, Diag};
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use rustc_errors::{Applicability, Diag, EmissionGuarantee};
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use rustc_hir as hir;
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use rustc_hir::intravisit::Visitor;
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use rustc_infer::infer::NllRegionVariableOrigin;
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@ -61,10 +61,10 @@ impl<'tcx> BorrowExplanation<'tcx> {
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pub(crate) fn is_explained(&self) -> bool {
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!matches!(self, BorrowExplanation::Unexplained)
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}
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pub(crate) fn add_explanation_to_diagnostic(
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pub(crate) fn add_explanation_to_diagnostic<G: EmissionGuarantee>(
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&self,
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cx: &MirBorrowckCtxt<'_, '_, 'tcx>,
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err: &mut Diag<'_>,
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err: &mut Diag<'_, G>,
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borrow_desc: &str,
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borrow_span: Option<Span>,
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multiple_borrow_span: Option<(Span, Span)>,
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@ -346,10 +346,10 @@ impl<'tcx> BorrowExplanation<'tcx> {
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}
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}
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fn add_object_lifetime_default_note(
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fn add_object_lifetime_default_note<G: EmissionGuarantee>(
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&self,
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tcx: TyCtxt<'tcx>,
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err: &mut Diag<'_>,
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err: &mut Diag<'_, G>,
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unsize_ty: Ty<'tcx>,
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) {
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if let ty::Adt(def, args) = unsize_ty.kind() {
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@ -403,9 +403,9 @@ impl<'tcx> BorrowExplanation<'tcx> {
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}
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}
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fn add_lifetime_bound_suggestion_to_diagnostic(
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fn add_lifetime_bound_suggestion_to_diagnostic<G: EmissionGuarantee>(
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&self,
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err: &mut Diag<'_>,
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err: &mut Diag<'_, G>,
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category: &ConstraintCategory<'tcx>,
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span: Span,
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region_name: &RegionName,
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@ -432,14 +432,14 @@ impl<'tcx> BorrowExplanation<'tcx> {
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}
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}
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fn suggest_rewrite_if_let(
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fn suggest_rewrite_if_let<G: EmissionGuarantee>(
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tcx: TyCtxt<'_>,
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expr: &hir::Expr<'_>,
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pat: &str,
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init: &hir::Expr<'_>,
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conseq: &hir::Expr<'_>,
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alt: Option<&hir::Expr<'_>>,
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err: &mut Diag<'_>,
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err: &mut Diag<'_, G>,
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) {
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let source_map = tcx.sess.source_map();
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err.span_note(
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@ -4,7 +4,7 @@ use std::collections::BTreeMap;
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use rustc_abi::{FieldIdx, VariantIdx};
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use rustc_data_structures::fx::FxIndexMap;
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use rustc_errors::{Applicability, Diag, MultiSpan};
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use rustc_errors::{Applicability, Diag, EmissionGuarantee, MultiSpan};
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use rustc_hir::def::{CtorKind, Namespace};
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use rustc_hir::{self as hir, CoroutineKind, LangItem};
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use rustc_index::IndexSlice;
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@ -626,9 +626,9 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
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/// Add a note to region errors and borrow explanations when higher-ranked regions in predicates
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/// implicitly introduce an "outlives `'static`" constraint.
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fn add_placeholder_from_predicate_note(
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fn add_placeholder_from_predicate_note<G: EmissionGuarantee>(
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&self,
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err: &mut Diag<'_>,
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err: &mut Diag<'_, G>,
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path: &[OutlivesConstraint<'tcx>],
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) {
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let predicate_span = path.iter().find_map(|constraint| {
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@ -651,9 +651,9 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
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/// Add a label to region errors and borrow explanations when outlives constraints arise from
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/// proving a type implements `Sized` or `Copy`.
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fn add_sized_or_copy_bound_info(
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fn add_sized_or_copy_bound_info<G: EmissionGuarantee>(
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&self,
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err: &mut Diag<'_>,
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err: &mut Diag<'_, G>,
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blamed_category: ConstraintCategory<'tcx>,
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path: &[OutlivesConstraint<'tcx>],
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) {
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@ -1042,6 +1042,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
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kind,
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};
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}
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normal_ret
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}
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@ -5,7 +5,7 @@ use std::fmt::{self, Display};
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use std::iter;
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use rustc_data_structures::fx::IndexEntry;
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use rustc_errors::Diag;
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use rustc_errors::{Diag, EmissionGuarantee};
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use rustc_hir as hir;
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use rustc_hir::def::{DefKind, Res};
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use rustc_middle::ty::print::RegionHighlightMode;
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@ -108,7 +108,7 @@ impl RegionName {
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}
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}
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pub(crate) fn highlight_region_name(&self, diag: &mut Diag<'_>) {
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pub(crate) fn highlight_region_name<G: EmissionGuarantee>(&self, diag: &mut Diag<'_, G>) {
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match &self.source {
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RegionNameSource::NamedLateParamRegion(span)
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| RegionNameSource::NamedEarlyParamRegion(span) => {
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@ -24,6 +24,7 @@ use std::ops::{ControlFlow, Deref};
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use rustc_abi::FieldIdx;
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use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
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use rustc_data_structures::graph::dominators::Dominators;
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use rustc_errors::LintDiagnostic;
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use rustc_hir as hir;
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use rustc_hir::CRATE_HIR_ID;
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use rustc_hir::def_id::LocalDefId;
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@ -1192,17 +1193,25 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> {
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|borrow_index| borrows_in_scope.contains(borrow_index),
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|this, _borrow_index, borrow| {
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if matches!(borrow.kind, BorrowKind::Fake(_)) {
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return Control::Continue;
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return ControlFlow::Continue(());
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}
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let borrowed = this.retrieve_borrow_spans(borrow).var_or_use_path_span();
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this.infcx.tcx.emit_node_span_lint(
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let explain = this.explain_why_borrow_contains_point(
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location,
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borrow,
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Some((WriteKind::StorageDeadOrDrop, place)),
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);
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this.infcx.tcx.node_span_lint(
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TAIL_EXPR_DROP_ORDER,
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CRATE_HIR_ID,
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place_span,
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session_diagnostics::TailExprDropOrder { borrowed },
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borrowed,
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|diag| {
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session_diagnostics::TailExprDropOrder { borrowed }.decorate_lint(diag);
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explain.add_explanation_to_diagnostic(&this, diag, "", None, None);
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},
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);
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// We may stop at the first case
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Control::Break
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ControlFlow::Break(())
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},
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);
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}
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@ -74,6 +74,7 @@ fn method_1(_1: Guard) -> () {
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bb7: {
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backward incompatible drop(_2);
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backward incompatible drop(_4);
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backward incompatible drop(_5);
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goto -> bb21;
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}
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@ -74,6 +74,7 @@ fn method_1(_1: Guard) -> () {
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bb7: {
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backward incompatible drop(_2);
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backward incompatible drop(_4);
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backward incompatible drop(_5);
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goto -> bb21;
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}
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@ -7,18 +7,20 @@
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fn should_lint_with_potential_borrowck_err() {
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let _ = { String::new().as_str() }.len();
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//~^ ERROR: a temporary value will be dropped here
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//~^ ERROR: relative drop order changing
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//~| WARN: this changes meaning in Rust 2024
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//~| NOTE: consider using a `let` binding
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//~| NOTE: this temporary value will be dropped at the end of the block
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//~| borrow later used by call
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//~| NOTE: for more information, see
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}
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fn should_lint_with_unsafe_block() {
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fn f(_: usize) {}
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f(unsafe { String::new().as_str() }.len());
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//~^ ERROR: a temporary value will be dropped here
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//~^ ERROR: relative drop order changing
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//~| WARN: this changes meaning in Rust 2024
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//~| NOTE: consider using a `let` binding
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//~| NOTE: this temporary value will be dropped at the end of the block
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//~| borrow later used by call
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//~| NOTE: for more information, see
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}
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@ -27,11 +29,23 @@ fn should_lint_with_big_block() {
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fn f<T>(_: T) {}
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f({
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&mut || 0
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//~^ ERROR: a temporary value will be dropped here
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//~^ ERROR: relative drop order changing
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//~| WARN: this changes meaning in Rust 2024
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//~| NOTE: consider using a `let` binding
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//~| NOTE: this temporary value will be dropped at the end of the block
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//~| borrow later used here
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//~| NOTE: for more information, see
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})
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}
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fn another_temp_that_is_copy_in_arg() {
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fn f() {}
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fn g(_: &()) {}
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g({ &f() });
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//~^ ERROR: relative drop order changing
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//~| WARN: this changes meaning in Rust 2024
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//~| NOTE: this temporary value will be dropped at the end of the block
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//~| borrow later used by call
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//~| NOTE: for more information, see
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}
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fn main() {}
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@ -1,10 +1,10 @@
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error: a temporary value will be dropped here before the execution exits the block in Edition 2024, which will raise borrow checking error
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--> $DIR/lint-tail-expr-drop-order-borrowck.rs:9:36
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error: relative drop order changing in Rust 2024
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--> $DIR/lint-tail-expr-drop-order-borrowck.rs:9:15
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LL | let _ = { String::new().as_str() }.len();
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| ------------- ^
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| ^^^^^^^^^^^^^ --- borrow later used by call
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| |
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| consider using a `let` binding to create a longer lived value; or replacing the `{ .. }` block with curly brackets `( .. )`; or folding the rest of the expression into the surrounding `unsafe { .. }`
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| this temporary value will be dropped at the end of the block
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= warning: this changes meaning in Rust 2024
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= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html>
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@ -14,27 +14,39 @@ note: the lint level is defined here
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LL | #![deny(tail_expr_drop_order)]
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| ^^^^^^^^^^^^^^^^^^^^
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error: a temporary value will be dropped here before the execution exits the block in Edition 2024, which will raise borrow checking error
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--> $DIR/lint-tail-expr-drop-order-borrowck.rs:18:37
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error: relative drop order changing in Rust 2024
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--> $DIR/lint-tail-expr-drop-order-borrowck.rs:19:16
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LL | f(unsafe { String::new().as_str() }.len());
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| ------------- ^
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| ^^^^^^^^^^^^^ --- borrow later used by call
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| |
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| consider using a `let` binding to create a longer lived value; or replacing the `{ .. }` block with curly brackets `( .. )`; or folding the rest of the expression into the surrounding `unsafe { .. }`
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| this temporary value will be dropped at the end of the block
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= warning: this changes meaning in Rust 2024
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= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html>
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error: a temporary value will be dropped here before the execution exits the block in Edition 2024, which will raise borrow checking error
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--> $DIR/lint-tail-expr-drop-order-borrowck.rs:29:17
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error: relative drop order changing in Rust 2024
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--> $DIR/lint-tail-expr-drop-order-borrowck.rs:31:9
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LL | &mut || 0
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| --------^
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| ^^^^^^^^^
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| |
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| consider using a `let` binding to create a longer lived value; or replacing the `{ .. }` block with curly brackets `( .. )`; or folding the rest of the expression into the surrounding `unsafe { .. }`
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| this temporary value will be dropped at the end of the block
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| borrow later used here
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= warning: this changes meaning in Rust 2024
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= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html>
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error: aborting due to 3 previous errors
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error: relative drop order changing in Rust 2024
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--> $DIR/lint-tail-expr-drop-order-borrowck.rs:43:9
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LL | g({ &f() });
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| - ^^^^ this temporary value will be dropped at the end of the block
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| |
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| borrow later used by call
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= warning: this changes meaning in Rust 2024
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= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html>
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error: aborting due to 4 previous errors
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