diff --git a/clippy_lints/src/matches/mod.rs b/clippy_lints/src/matches/mod.rs index 3e765173fb9f..d43ad1b8c9c6 100644 --- a/clippy_lints/src/matches/mod.rs +++ b/clippy_lints/src/matches/mod.rs @@ -963,7 +963,7 @@ impl<'tcx> LateLintPass<'tcx> for Matches { return; } if matches!(source, MatchSource::Normal | MatchSource::ForLoopDesugar) { - significant_drop_in_scrutinee::check(cx, expr, ex, source); + significant_drop_in_scrutinee::check(cx, expr, ex, arms, source); } collapsible_match::check_match(cx, arms); diff --git a/clippy_lints/src/matches/significant_drop_in_scrutinee.rs b/clippy_lints/src/matches/significant_drop_in_scrutinee.rs index dcaf6f865de3..0704a5af5259 100644 --- a/clippy_lints/src/matches/significant_drop_in_scrutinee.rs +++ b/clippy_lints/src/matches/significant_drop_in_scrutinee.rs @@ -1,10 +1,10 @@ use crate::FxHashSet; use clippy_utils::diagnostics::span_lint_and_then; -use clippy_utils::get_attr; use clippy_utils::source::{indent_of, snippet}; +use clippy_utils::{get_attr, is_lint_allowed}; use rustc_errors::{Applicability, Diagnostic}; use rustc_hir::intravisit::{walk_expr, Visitor}; -use rustc_hir::{Expr, ExprKind, MatchSource}; +use rustc_hir::{Arm, Expr, ExprKind, MatchSource}; use rustc_lint::{LateContext, LintContext}; use rustc_middle::ty::subst::GenericArgKind; use rustc_middle::ty::{Ty, TypeAndMut}; @@ -16,12 +16,23 @@ pub(super) fn check<'tcx>( cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, scrutinee: &'tcx Expr<'_>, + arms: &'tcx [Arm<'_>], source: MatchSource, ) { + if is_lint_allowed(cx, SIGNIFICANT_DROP_IN_SCRUTINEE, expr.hir_id) { + return; + } + if let Some((suggestions, message)) = has_significant_drop_in_scrutinee(cx, scrutinee, source) { for found in suggestions { span_lint_and_then(cx, SIGNIFICANT_DROP_IN_SCRUTINEE, found.found_span, message, |diag| { set_diagnostic(diag, cx, expr, found); + let s = Span::new(expr.span.hi(), expr.span.hi(), expr.span.ctxt(), None); + diag.span_label(s, "temporary lives until here"); + for span in has_significant_drop_in_arms(cx, arms) { + diag.span_label(span, "another value with significant `Drop` created here"); + } + diag.note("this might lead to deadlocks or other unexpected behavior"); }); } } @@ -80,22 +91,77 @@ fn has_significant_drop_in_scrutinee<'tcx, 'a>( let mut helper = SigDropHelper::new(cx); helper.find_sig_drop(scrutinee).map(|drops| { let message = if source == MatchSource::Normal { - "temporary with significant drop in match scrutinee" + "temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression" } else { - "temporary with significant drop in for loop" + "temporary with significant `Drop` in `for` loop condition will live until the end of the `for` expression" }; (drops, message) }) } +struct SigDropChecker<'a, 'tcx> { + seen_types: FxHashSet>, + cx: &'a LateContext<'tcx>, +} + +impl<'a, 'tcx> SigDropChecker<'a, 'tcx> { + fn new(cx: &'a LateContext<'tcx>) -> SigDropChecker<'a, 'tcx> { + SigDropChecker { + seen_types: FxHashSet::default(), + cx, + } + } + + fn get_type(&self, ex: &'tcx Expr<'_>) -> Ty<'tcx> { + self.cx.typeck_results().expr_ty(ex) + } + + fn has_seen_type(&mut self, ty: Ty<'tcx>) -> bool { + !self.seen_types.insert(ty) + } + + fn has_sig_drop_attr(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool { + if let Some(adt) = ty.ty_adt_def() { + if get_attr(cx.sess(), cx.tcx.get_attrs_unchecked(adt.did()), "has_significant_drop").count() > 0 { + return true; + } + } + + match ty.kind() { + rustc_middle::ty::Adt(a, b) => { + for f in a.all_fields() { + let ty = f.ty(cx.tcx, b); + if !self.has_seen_type(ty) && self.has_sig_drop_attr(cx, ty) { + return true; + } + } + + for generic_arg in b.iter() { + if let GenericArgKind::Type(ty) = generic_arg.unpack() { + if self.has_sig_drop_attr(cx, ty) { + return true; + } + } + } + false + }, + rustc_middle::ty::Array(ty, _) + | rustc_middle::ty::RawPtr(TypeAndMut { ty, .. }) + | rustc_middle::ty::Ref(_, ty, _) + | rustc_middle::ty::Slice(ty) => self.has_sig_drop_attr(cx, *ty), + _ => false, + } + } +} + struct SigDropHelper<'a, 'tcx> { cx: &'a LateContext<'tcx>, is_chain_end: bool, - seen_types: FxHashSet>, has_significant_drop: bool, current_sig_drop: Option, sig_drop_spans: Option>, special_handling_for_binary_op: bool, + sig_drop_checker: SigDropChecker<'a, 'tcx>, } #[expect(clippy::enum_variant_names)] @@ -118,11 +184,11 @@ impl<'a, 'tcx> SigDropHelper<'a, 'tcx> { SigDropHelper { cx, is_chain_end: true, - seen_types: FxHashSet::default(), has_significant_drop: false, current_sig_drop: None, sig_drop_spans: None, special_handling_for_binary_op: false, + sig_drop_checker: SigDropChecker::new(cx), } } @@ -163,7 +229,7 @@ impl<'a, 'tcx> SigDropHelper<'a, 'tcx> { if self.current_sig_drop.is_some() { return; } - let ty = self.get_type(expr); + let ty = self.sig_drop_checker.get_type(expr); if ty.is_ref() { // We checked that the type was ref, so builtin_deref will return Some TypeAndMut, // but let's avoid any chance of an ICE @@ -187,14 +253,6 @@ impl<'a, 'tcx> SigDropHelper<'a, 'tcx> { } } - fn get_type(&self, ex: &'tcx Expr<'_>) -> Ty<'tcx> { - self.cx.typeck_results().expr_ty(ex) - } - - fn has_seen_type(&mut self, ty: Ty<'tcx>) -> bool { - !self.seen_types.insert(ty) - } - fn visit_exprs_for_binary_ops( &mut self, left: &'tcx Expr<'_>, @@ -214,44 +272,15 @@ impl<'a, 'tcx> SigDropHelper<'a, 'tcx> { self.special_handling_for_binary_op = false; } - - fn has_sig_drop_attr(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool { - if let Some(adt) = ty.ty_adt_def() { - if get_attr(cx.sess(), cx.tcx.get_attrs_unchecked(adt.did()), "has_significant_drop").count() > 0 { - return true; - } - } - - match ty.kind() { - rustc_middle::ty::Adt(a, b) => { - for f in a.all_fields() { - let ty = f.ty(cx.tcx, b); - if !self.has_seen_type(ty) && self.has_sig_drop_attr(cx, ty) { - return true; - } - } - - for generic_arg in b.iter() { - if let GenericArgKind::Type(ty) = generic_arg.unpack() { - if self.has_sig_drop_attr(cx, ty) { - return true; - } - } - } - false - }, - rustc_middle::ty::Array(ty, _) - | rustc_middle::ty::RawPtr(TypeAndMut { ty, .. }) - | rustc_middle::ty::Ref(_, ty, _) - | rustc_middle::ty::Slice(ty) => self.has_sig_drop_attr(cx, *ty), - _ => false, - } - } } impl<'a, 'tcx> Visitor<'tcx> for SigDropHelper<'a, 'tcx> { fn visit_expr(&mut self, ex: &'tcx Expr<'_>) { - if !self.is_chain_end && self.has_sig_drop_attr(self.cx, self.get_type(ex)) { + if !self.is_chain_end + && self + .sig_drop_checker + .has_sig_drop_attr(self.cx, self.sig_drop_checker.get_type(ex)) + { self.has_significant_drop = true; return; } @@ -330,3 +359,38 @@ impl<'a, 'tcx> Visitor<'tcx> for SigDropHelper<'a, 'tcx> { } } } + +struct ArmSigDropHelper<'a, 'tcx> { + sig_drop_checker: SigDropChecker<'a, 'tcx>, + found_sig_drop_spans: FxHashSet, +} + +impl<'a, 'tcx> ArmSigDropHelper<'a, 'tcx> { + fn new(cx: &'a LateContext<'tcx>) -> ArmSigDropHelper<'a, 'tcx> { + ArmSigDropHelper { + sig_drop_checker: SigDropChecker::new(cx), + found_sig_drop_spans: FxHashSet::::default(), + } + } +} + +fn has_significant_drop_in_arms<'tcx, 'a>(cx: &'a LateContext<'tcx>, arms: &'tcx [Arm<'_>]) -> FxHashSet { + let mut helper = ArmSigDropHelper::new(cx); + for arm in arms { + helper.visit_expr(arm.body); + } + helper.found_sig_drop_spans +} + +impl<'a, 'tcx> Visitor<'tcx> for ArmSigDropHelper<'a, 'tcx> { + fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) { + if self + .sig_drop_checker + .has_sig_drop_attr(self.sig_drop_checker.cx, self.sig_drop_checker.get_type(ex)) + { + self.found_sig_drop_spans.insert(ex.span); + return; + } + walk_expr(self, ex); + } +} diff --git a/tests/ui/significant_drop_in_scrutinee.rs b/tests/ui/significant_drop_in_scrutinee.rs index 4347610f393f..185e5009b60f 100644 --- a/tests/ui/significant_drop_in_scrutinee.rs +++ b/tests/ui/significant_drop_in_scrutinee.rs @@ -64,6 +64,19 @@ fn should_trigger_lint_with_mutex_guard_in_match_scrutinee() { }; } +fn should_not_trigger_lint_with_mutex_guard_in_match_scrutinee_when_lint_allowed() { + let mutex = Mutex::new(State {}); + + // Lint should not be triggered because it is "allowed" below. + #[allow(clippy::significant_drop_in_scrutinee)] + match mutex.lock().unwrap().foo() { + true => { + mutex.lock().unwrap().bar(); + }, + false => {}, + }; +} + fn should_not_trigger_lint_for_insignificant_drop() { // Should not trigger lint because there are no temporaries whose drops have a significant // side effect. @@ -591,4 +604,20 @@ fn should_trigger_lint_for_read_write_lock_for_loop() { } } +fn do_bar(mutex: &Mutex) { + mutex.lock().unwrap().bar(); +} + +fn should_trigger_lint_without_significant_drop_in_arm() { + let mutex = Mutex::new(State {}); + + // Should trigger lint because the lifetime of the temporary MutexGuard is surprising because it + // is preserved until the end of the match, but there is no clear indication that this is the + // case. + match mutex.lock().unwrap().foo() { + true => do_bar(&mutex), + false => {}, + }; +} + fn main() {} diff --git a/tests/ui/significant_drop_in_scrutinee.stderr b/tests/ui/significant_drop_in_scrutinee.stderr index 303f3c1df033..dbb41837e790 100644 --- a/tests/ui/significant_drop_in_scrutinee.stderr +++ b/tests/ui/significant_drop_in_scrutinee.stderr @@ -1,174 +1,290 @@ -error: temporary with significant drop in match scrutinee +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression --> $DIR/significant_drop_in_scrutinee.rs:59:11 | LL | match mutex.lock().unwrap().foo() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | true => { +LL | mutex.lock().unwrap().bar(); + | --------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here | = note: `-D clippy::significant-drop-in-scrutinee` implied by `-D warnings` + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex.lock().unwrap().foo(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:132:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:145:11 | LL | match s.lock_m().get_the_value() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | println!("{}", s.lock_m().get_the_value()); + | ---------- another value with significant `Drop` created here +... +LL | } + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = s.lock_m().get_the_value(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:153:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:166:11 | LL | match s.lock_m_m().get_the_value() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | println!("{}", s.lock_m().get_the_value()); + | ---------- another value with significant `Drop` created here +... +LL | } + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = s.lock_m_m().get_the_value(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:201:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:214:11 | LL | match counter.temp_increment().len() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +... +LL | }; + | - temporary lives until here | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = counter.temp_increment().len(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:224:16 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:237:16 | LL | match (mutex1.lock().unwrap().s.len(), true) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex1.lock().unwrap().s.len(); LL ~ match (value, true) { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:233:22 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:246:22 | LL | match (true, mutex1.lock().unwrap().s.len(), true) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex1.lock().unwrap().s.len(); LL ~ match (true, value, true) { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:243:16 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:256:16 | LL | match (mutex1.lock().unwrap().s.len(), true, mutex2.lock().unwrap().s.len()) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +LL | mutex2.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex1.lock().unwrap().s.len(); LL ~ match (value, true, mutex2.lock().unwrap().s.len()) { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:243:54 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:256:54 | LL | match (mutex1.lock().unwrap().s.len(), true, mutex2.lock().unwrap().s.len()) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +LL | mutex2.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex2.lock().unwrap().s.len(); LL ~ match (mutex1.lock().unwrap().s.len(), true, value) { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:254:15 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:267:15 | LL | match mutex3.lock().unwrap().s.as_str() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +LL | mutex2.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:264:22 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:277:22 | LL | match (true, mutex3.lock().unwrap().s.as_str()) { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +LL | mutex2.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:283:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:296:11 | LL | match mutex.lock().unwrap().s.len() > 1 { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +LL | true => { +LL | mutex.lock().unwrap().s.len(); + | --------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex.lock().unwrap().s.len() > 1; LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:290:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:303:11 | LL | match 1 < mutex.lock().unwrap().s.len() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +LL | true => { +LL | mutex.lock().unwrap().s.len(); + | --------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = 1 < mutex.lock().unwrap().s.len(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:308:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:321:11 | LL | match mutex1.lock().unwrap().s.len() < mutex2.lock().unwrap().s.len() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | mutex1.lock().unwrap().s.len(), + | ---------------------- another value with significant `Drop` created here +LL | mutex2.lock().unwrap().s.len() + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex1.lock().unwrap().s.len() < mutex2.lock().unwrap().s.len(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:319:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:332:11 | LL | match mutex1.lock().unwrap().s.len() >= mutex2.lock().unwrap().s.len() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +... +LL | mutex1.lock().unwrap().s.len(), + | ---------------------- another value with significant `Drop` created here +LL | mutex2.lock().unwrap().s.len() + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = mutex1.lock().unwrap().s.len() >= mutex2.lock().unwrap().s.len(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:354:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:367:11 | LL | match get_mutex_guard().s.len() > 1 { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +LL | true => { +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = get_mutex_guard().s.len() > 1; LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:371:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:384:11 | LL | match match i { | ___________^ @@ -179,7 +295,14 @@ LL | | .s LL | | .len() LL | | > 1 | |___________^ - | +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = match i { @@ -190,8 +313,8 @@ LL + .s LL + .len() ... -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:397:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:410:11 | LL | match if i > 1 { | ___________^ @@ -202,7 +325,14 @@ LL | | mutex2.lock().unwrap() LL | | .len() LL | | > 1 | |___________^ - | +... +LL | mutex1.lock().unwrap().s.len(); + | ---------------------- another value with significant `Drop` created here +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ let value = if i > 1 { @@ -213,83 +343,150 @@ LL + } LL + .s ... -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:451:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:464:11 | LL | match s.lock().deref().deref() { | ^^^^^^^^^^^^^^^^^^^^^^^^ +LL | 0 | 1 => println!("Value was less than 2"), +LL | _ => println!("Value is {}", s.lock().deref()), + | ---------------- another value with significant `Drop` created here +LL | }; + | - temporary lives until here | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match and create a copy | LL ~ let value = *s.lock().deref().deref(); LL ~ match value { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:479:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:492:11 | LL | match s.lock().deref().deref() { | ^^^^^^^^^^^^^^^^^^^^^^^^ +LL | matcher => println!("Value is {}", s.lock().deref()), + | ---------------- another value with significant `Drop` created here +LL | _ => println!("Value was not a match"), +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:498:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:511:11 | LL | match mutex.lock().unwrap().i = i { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +LL | _ => { +LL | println!("{}", mutex.lock().unwrap().i); + | --------------------- another value with significant `Drop` created here +LL | }, +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ mutex.lock().unwrap().i = i; LL ~ match () { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:504:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:517:11 | LL | match i = mutex.lock().unwrap().i { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +LL | _ => { +LL | println!("{}", mutex.lock().unwrap().i); + | --------------------- another value with significant `Drop` created here +LL | }, +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ i = mutex.lock().unwrap().i; LL ~ match () { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:510:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:523:11 | LL | match mutex.lock().unwrap().i += 1 { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +LL | _ => { +LL | println!("{}", mutex.lock().unwrap().i); + | --------------------- another value with significant `Drop` created here +LL | }, +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ mutex.lock().unwrap().i += 1; LL ~ match () { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:516:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:529:11 | LL | match i += mutex.lock().unwrap().i { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | +LL | _ => { +LL | println!("{}", mutex.lock().unwrap().i); + | --------------------- another value with significant `Drop` created here +LL | }, +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior help: try moving the temporary above the match | LL ~ i += mutex.lock().unwrap().i; LL ~ match () { | -error: temporary with significant drop in match scrutinee - --> $DIR/significant_drop_in_scrutinee.rs:579:11 +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:592:11 | LL | match rwlock.read().unwrap().to_number() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior -error: temporary with significant drop in for loop - --> $DIR/significant_drop_in_scrutinee.rs:589:14 +error: temporary with significant `Drop` in `for` loop condition will live until the end of the `for` expression + --> $DIR/significant_drop_in_scrutinee.rs:602:14 | LL | for s in rwlock.read().unwrap().iter() { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | println!("{}", s); +LL | } + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior + +error: temporary with significant `Drop` in `match` scrutinee will live until the end of the `match` expression + --> $DIR/significant_drop_in_scrutinee.rs:617:11 + | +LL | match mutex.lock().unwrap().foo() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ +... +LL | }; + | - temporary lives until here + | + = note: this might lead to deadlocks or other unexpected behavior +help: try moving the temporary above the match + | +LL ~ let value = mutex.lock().unwrap().foo(); +LL ~ match value { + | -error: aborting due to 25 previous errors +error: aborting due to 26 previous errors