diff options
Diffstat (limited to 'tests')
| -rw-r--r-- | tests/ui/significant_drop_in_scrutinee.rs | 526 | ||||
| -rw-r--r-- | tests/ui/significant_drop_in_scrutinee.stderr | 261 |
2 files changed, 787 insertions, 0 deletions
diff --git a/tests/ui/significant_drop_in_scrutinee.rs b/tests/ui/significant_drop_in_scrutinee.rs new file mode 100644 index 00000000000..c4a3301e722 --- /dev/null +++ b/tests/ui/significant_drop_in_scrutinee.rs @@ -0,0 +1,526 @@ +// FIXME: Ideally these suggestions would be fixed via rustfix. Blocked by rust-lang/rust#53934 +// // run-rustfix + +#![warn(clippy::significant_drop_in_scrutinee)] +#![allow(clippy::single_match)] +#![allow(clippy::match_single_binding)] +#![allow(unused_assignments)] +#![allow(dead_code)] + +use std::ops::Deref; +use std::sync::atomic::{AtomicU64, Ordering}; +use std::sync::{Mutex, MutexGuard}; + +struct State {} + +impl State { + fn foo(&self) -> bool { + true + } + + fn bar(&self) {} +} + +fn should_not_trigger_lint_with_mutex_guard_outside_match() { + let mutex = Mutex::new(State {}); + + // Should not trigger lint because the temporary should drop at the `;` on line before the match + let is_foo = mutex.lock().unwrap().foo(); + match is_foo { + true => { + mutex.lock().unwrap().bar(); + } + false => {} + }; +} + +fn should_not_trigger_lint_with_mutex_guard_when_taking_ownership_in_match() { + let mutex = Mutex::new(State {}); + + // Should not trigger lint because the scrutinee is explicitly returning the MutexGuard, + // so its lifetime should not be surprising. + match mutex.lock() { + Ok(guard) => { + guard.foo(); + mutex.lock().unwrap().bar(); + } + _ => {} + }; +} + +fn should_trigger_lint_with_mutex_guard_in_match_scrutinee() { + 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 => { + 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. + match 1u64.to_string().is_empty() { + true => { + println!("It was empty") + } + false => { + println!("It was not empty") + } + } +} + +struct StateWithMutex { + m: Mutex<u64>, +} + +struct MutexGuardWrapper<'a> { + mg: MutexGuard<'a, u64>, +} + +impl<'a> MutexGuardWrapper<'a> { + fn get_the_value(&self) -> u64 { + *self.mg.deref() + } +} + +struct MutexGuardWrapperWrapper<'a> { + mg: MutexGuardWrapper<'a>, +} + +impl<'a> MutexGuardWrapperWrapper<'a> { + fn get_the_value(&self) -> u64 { + *self.mg.mg.deref() + } +} + +impl StateWithMutex { + fn lock_m(&self) -> MutexGuardWrapper<'_> { + MutexGuardWrapper { + mg: self.m.lock().unwrap(), + } + } + + fn lock_m_m(&self) -> MutexGuardWrapperWrapper<'_> { + MutexGuardWrapperWrapper { + mg: MutexGuardWrapper { + mg: self.m.lock().unwrap(), + }, + } + } + + fn foo(&self) -> bool { + true + } + + fn bar(&self) {} +} + +fn should_trigger_lint_with_wrapped_mutex() { + let s = StateWithMutex { m: Mutex::new(1) }; + + // Should trigger lint because a temporary contains a type with a significant drop and its + // lifetime is not obvious. Additionally, it is not obvious from looking at the scrutinee that + // the temporary contains such a type, making it potentially even more surprising. + match s.lock_m().get_the_value() { + 1 => { + println!("Got 1. Is it still 1?"); + println!("{}", s.lock_m().get_the_value()); + } + 2 => { + println!("Got 2. Is it still 2?"); + println!("{}", s.lock_m().get_the_value()); + } + _ => {} + } + println!("All done!"); +} + +fn should_trigger_lint_with_double_wrapped_mutex() { + let s = StateWithMutex { m: Mutex::new(1) }; + + // Should trigger lint because a temporary contains a type which further contains a type with a + // significant drop and its lifetime is not obvious. Additionally, it is not obvious from + // looking at the scrutinee that the temporary contains such a type, making it potentially even + // more surprising. + match s.lock_m_m().get_the_value() { + 1 => { + println!("Got 1. Is it still 1?"); + println!("{}", s.lock_m().get_the_value()); + } + 2 => { + println!("Got 2. Is it still 2?"); + println!("{}", s.lock_m().get_the_value()); + } + _ => {} + } + println!("All done!"); +} + +struct Counter { + i: AtomicU64, +} + +#[clippy::has_significant_drop] +struct CounterWrapper<'a> { + counter: &'a Counter, +} + +impl<'a> CounterWrapper<'a> { + fn new(counter: &Counter) -> CounterWrapper { + counter.i.fetch_add(1, Ordering::Relaxed); + CounterWrapper { counter } + } +} + +impl<'a> Drop for CounterWrapper<'a> { + fn drop(&mut self) { + self.counter.i.fetch_sub(1, Ordering::Relaxed); + } +} + +impl Counter { + fn temp_increment(&self) -> Vec<CounterWrapper> { + vec![CounterWrapper::new(self), CounterWrapper::new(self)] + } +} + +fn should_trigger_lint_for_vec() { + let counter = Counter { i: AtomicU64::new(0) }; + + // Should trigger lint because the temporary in the scrutinee returns a collection of types + // which have significant drops. The types with significant drops are also non-obvious when + // reading the expression in the scrutinee. + match counter.temp_increment().len() { + 2 => { + let current_count = counter.i.load(Ordering::Relaxed); + println!("Current count {}", current_count); + assert_eq!(current_count, 0); + } + 1 => {} + 3 => {} + _ => {} + }; +} + +struct StateWithField { + s: String, +} + +// Should trigger lint only on the type in the tuple which is created using a temporary +// with a significant drop. Additionally, this test ensures that the format of the tuple +// is preserved correctly in the suggestion. +fn should_trigger_lint_for_tuple_in_scrutinee() { + let mutex1 = Mutex::new(StateWithField { s: "one".to_owned() }); + + { + match (mutex1.lock().unwrap().s.len(), true) { + (3, _) => { + println!("started"); + mutex1.lock().unwrap().s.len(); + println!("done"); + } + (_, _) => {} + }; + + match (true, mutex1.lock().unwrap().s.len(), true) { + (_, 3, _) => { + println!("started"); + mutex1.lock().unwrap().s.len(); + println!("done"); + } + (_, _, _) => {} + }; + + let mutex2 = Mutex::new(StateWithField { s: "two".to_owned() }); + match (mutex1.lock().unwrap().s.len(), true, mutex2.lock().unwrap().s.len()) { + (3, _, 3) => { + println!("started"); + mutex1.lock().unwrap().s.len(); + mutex2.lock().unwrap().s.len(); + println!("done"); + } + (_, _, _) => {} + }; + + let mutex3 = Mutex::new(StateWithField { s: "three".to_owned() }); + match mutex3.lock().unwrap().s.as_str() { + "three" => { + println!("started"); + mutex1.lock().unwrap().s.len(); + mutex2.lock().unwrap().s.len(); + println!("done"); + } + _ => {} + }; + + + match (true, mutex3.lock().unwrap().s.as_str()) { + (_, "three") => { + println!("started"); + mutex1.lock().unwrap().s.len(); + mutex2.lock().unwrap().s.len(); + println!("done"); + } + (_, _) => {} + }; + } +} + +// Should trigger lint when either side of a binary operation creates a temporary with a +// significant drop. +// To avoid potential unnecessary copies or creating references that would trigger the significant +// drop problem, the lint recommends moving the entire binary operation. +fn should_trigger_lint_for_accessing_field_in_mutex_in_one_side_of_binary_op() { + let mutex = Mutex::new(StateWithField { s: "state".to_owned() }); + + match mutex.lock().unwrap().s.len() > 1 { + true => { + mutex.lock().unwrap().s.len(); + } + false => {} + }; + + match 1 < mutex.lock().unwrap().s.len() { + true => { + mutex.lock().unwrap().s.len(); + } + false => {} + }; +} + +// Should trigger lint when both sides of a binary operation creates a temporary with a +// significant drop. +// To avoid potential unnecessary copies or creating references that would trigger the significant +// drop problem, the lint recommends moving the entire binary operation. +fn should_trigger_lint_for_accessing_fields_in_mutex_in_both_sides_of_binary_op() { + let mutex1 = Mutex::new(StateWithField { s: "state".to_owned() }); + let mutex2 = Mutex::new(StateWithField { s: "statewithfield".to_owned() }); + + match mutex1.lock().unwrap().s.len() < mutex2.lock().unwrap().s.len() { + true => { + println!("{} < {}", mutex1.lock().unwrap().s.len(), mutex2.lock().unwrap().s.len()); + } + false => {} + }; + + match mutex1.lock().unwrap().s.len() >= mutex2.lock().unwrap().s.len() { + true => { + println!("{} >= {}", mutex1.lock().unwrap().s.len(), mutex2.lock().unwrap().s.len()); + } + false => {} + }; +} + +fn should_not_trigger_lint_for_closure_in_scrutinee() { + let mutex1 = Mutex::new(StateWithField { s: "one".to_owned() }); + + let get_mutex_guard = || mutex1.lock().unwrap().s.len(); + + // Should not trigger lint because the temporary with a significant drop will be dropped + // at the end of the closure, so the MutexGuard will be unlocked and not have a potentially + // surprising lifetime. + match get_mutex_guard() > 1 { + true => { + mutex1.lock().unwrap().s.len(); + } + false => {} + }; +} + +fn should_trigger_lint_for_return_from_closure_in_scrutinee() { + let mutex1 = Mutex::new(StateWithField { s: "one".to_owned() }); + + let get_mutex_guard = || mutex1.lock().unwrap(); + + // Should trigger lint because the temporary with a significant drop is returned from the + // closure but not used directly in any match arms, so it has a potentially surprising lifetime. + match get_mutex_guard().s.len() > 1 { + true => { + mutex1.lock().unwrap().s.len(); + } + false => {} + }; +} + +fn should_trigger_lint_for_return_from_match_in_scrutinee() { + let mutex1 = Mutex::new(StateWithField { s: "one".to_owned() }); + let mutex2 = Mutex::new(StateWithField { s: "two".to_owned() }); + + let i = 100; + + // Should trigger lint because the nested match within the scrutinee returns a temporary with a + // significant drop is but not used directly in any match arms, so it has a potentially + // surprising lifetime. + match match i { 100 => mutex1.lock().unwrap(), _ => mutex2.lock().unwrap() }.s.len() > 1 { + true => { + mutex1.lock().unwrap().s.len(); + } + false => { + println!("nothing to do here"); + } + }; +} + +fn should_trigger_lint_for_return_from_if_in_scrutinee() { + let mutex1 = Mutex::new(StateWithField { s: "one".to_owned() }); + let mutex2 = Mutex::new(StateWithField { s: "two".to_owned() }); + + let i = 100; + + // Should trigger lint because the nested if-expression within the scrutinee returns a temporary + // with a significant drop is but not used directly in any match arms, so it has a potentially + // surprising lifetime. + match if i > 1 { mutex1.lock().unwrap() } else { mutex2.lock().unwrap() }.s.len() > 1 { + true => { + mutex1.lock().unwrap().s.len(); + } + false => {} + }; +} + +fn should_not_trigger_lint_for_if_in_scrutinee() { + let mutex = Mutex::new(StateWithField { s: "state".to_owned() }); + + let i = 100; + + // Should not trigger the lint because the temporary with a significant drop *is* dropped within + // the body of the if-expression nested within the match scrutinee, and therefore does not have + // a potentially surprising lifetime. + match if i > 1 { mutex.lock().unwrap().s.len() > 1 } else { false } { + true => { + mutex.lock().unwrap().s.len(); + } + false => {} + }; +} + +struct StateWithBoxedMutexGuard { + u: Mutex<u64>, +} + +impl StateWithBoxedMutexGuard { + fn new() -> StateWithBoxedMutexGuard { + StateWithBoxedMutexGuard { u: Mutex::new(42) } + } + fn lock(&self) -> Box<MutexGuard<u64>> { + Box::new(self.u.lock().unwrap()) + } +} + +fn should_trigger_lint_for_boxed_mutex_guard() { + let s = StateWithBoxedMutexGuard::new(); + + // Should trigger lint because a temporary Box holding a type with a significant drop in a match + // scrutinee may have a potentially surprising lifetime. + match s.lock().deref().deref() { + 0 | 1 => println!("Value was less than 2"), + _ => println!("Value is {}", s.lock().deref()), + }; +} + +struct StateStringWithBoxedMutexGuard { + s: Mutex<String>, +} + +impl StateStringWithBoxedMutexGuard { + fn new() -> StateStringWithBoxedMutexGuard { + StateStringWithBoxedMutexGuard { s: Mutex::new("A String".to_owned()) } + } + fn lock(&self) -> Box<MutexGuard<String>> { + Box::new(self.s.lock().unwrap()) + } +} + +fn should_trigger_lint_for_boxed_mutex_guard_holding_string() { + let s = StateStringWithBoxedMutexGuard::new(); + + let matcher = String::from("A String"); + + // Should trigger lint because a temporary Box holding a type with a significant drop in a match + // scrutinee may have a potentially surprising lifetime. + match s.lock().deref().deref() { + matcher => println!("Value is {}", s.lock().deref()), + _ => println!("Value was not a match"), + }; +} + + +struct StateWithIntField { + i: u64, +} + +// Should trigger lint when either side of an assign expression contains a temporary with a +// significant drop, because the temporary's lifetime will be extended to the end of the match. +// To avoid potential unnecessary copies or creating references that would trigger the significant +// drop problem, the lint recommends moving the entire binary operation. +fn should_trigger_lint_in_assign_expr() { + let mutex = Mutex::new(StateWithIntField { i: 10 }); + + let mut i = 100; + + match mutex.lock().unwrap().i = i { + _ => { + println!("{}", mutex.lock().unwrap().i); + } + }; + + match i = mutex.lock().unwrap().i { + _ => { + println!("{}", mutex.lock().unwrap().i); + } + }; + + match mutex.lock().unwrap().i += 1 { + _ => { + println!("{}", mutex.lock().unwrap().i); + } + }; + + match i += mutex.lock().unwrap().i { + _ => { + println!("{}", mutex.lock().unwrap().i); + } + }; +} + +#[derive(Debug)] +enum RecursiveEnum { + Foo(Option<Box<RecursiveEnum>>) +} + +#[derive(Debug)] +enum GenericRecursiveEnum<T> { + Foo(T, Option<Box<GenericRecursiveEnum<T>>>) +} + +fn should_not_cause_stack_overflow() { + // Test that when a type recursively contains itself, a stack overflow does not occur when + // checking sub-types for significant drops. + let f = RecursiveEnum::Foo(Some(Box::new(RecursiveEnum::Foo(None)))); + match f { + RecursiveEnum::Foo(Some(f)) => { + println!("{:?}", f) + } + RecursiveEnum::Foo(f) => { + println!("{:?}", f) + } + } + + let f = GenericRecursiveEnum::Foo(1u64, Some(Box::new(GenericRecursiveEnum::Foo(2u64, None)))); + match f { + GenericRecursiveEnum::Foo(i, Some(f)) => { + println!("{} {:?}", i, f) + } + GenericRecursiveEnum::Foo(i, f) => { + println!("{} {:?}", i, f) + } + } +} + +fn main() {} diff --git a/tests/ui/significant_drop_in_scrutinee.stderr b/tests/ui/significant_drop_in_scrutinee.stderr new file mode 100644 index 00000000000..c442e93f539 --- /dev/null +++ b/tests/ui/significant_drop_in_scrutinee.stderr @@ -0,0 +1,261 @@ +error: temporary with significant drop in match scrutinee + --> $DIR/significant_drop_in_scrutinee.rs:57:11 + | +LL | match mutex.lock().unwrap().foo() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: `-D clippy::significant-drop-in-scrutinee` implied by `-D warnings` +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:130:11 + | +LL | match s.lock_m().get_the_value() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:151:11 + | +LL | match s.lock_m_m().get_the_value() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:199:11 + | +LL | match counter.temp_increment().len() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:222:16 + | +LL | match (mutex1.lock().unwrap().s.len(), true) { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:231:22 + | +LL | match (true, mutex1.lock().unwrap().s.len(), true) { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:241:16 + | +LL | match (mutex1.lock().unwrap().s.len(), true, mutex2.lock().unwrap().s.len()) { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:241:54 + | +LL | match (mutex1.lock().unwrap().s.len(), true, mutex2.lock().unwrap().s.len()) { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:252:15 + | +LL | match mutex3.lock().unwrap().s.as_str() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: temporary with significant drop in match scrutinee + --> $DIR/significant_drop_in_scrutinee.rs:263:22 + | +LL | match (true, mutex3.lock().unwrap().s.as_str()) { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: temporary with significant drop in match scrutinee + --> $DIR/significant_drop_in_scrutinee.rs:282:11 + | +LL | match mutex.lock().unwrap().s.len() > 1 { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:289:11 + | +LL | match 1 < mutex.lock().unwrap().s.len() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:305:11 + | +LL | match mutex1.lock().unwrap().s.len() < mutex2.lock().unwrap().s.len() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:312:11 + | +LL | match mutex1.lock().unwrap().s.len() >= mutex2.lock().unwrap().s.len() { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:343:11 + | +LL | match get_mutex_guard().s.len() > 1 { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:360:11 + | +LL | match match i { 100 => mutex1.lock().unwrap(), _ => mutex2.lock().unwrap() }.s.len() > 1 { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try moving the temporary above the match + | +LL ~ let value = match i { 100 => mutex1.lock().unwrap(), _ => mutex2.lock().unwrap() }.s.len() > 1; +LL ~ match value { + | + +error: temporary with significant drop in match scrutinee + --> $DIR/significant_drop_in_scrutinee.rs:379:11 + | +LL | match if i > 1 { mutex1.lock().unwrap() } else { mutex2.lock().unwrap() }.s.len() > 1 { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try moving the temporary above the match + | +LL ~ let value = if i > 1 { mutex1.lock().unwrap() } else { mutex2.lock().unwrap() }.s.len() > 1; +LL ~ match value { + | + +error: temporary with significant drop in match scrutinee + --> $DIR/significant_drop_in_scrutinee.rs:421:11 + | +LL | match s.lock().deref().deref() { + | ^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:447:11 + | +LL | match s.lock().deref().deref() { + | ^^^^^^^^^^^^^^^^^^^^^^^^ + +error: temporary with significant drop in match scrutinee + --> $DIR/significant_drop_in_scrutinee.rs:467:11 + | +LL | match mutex.lock().unwrap().i = i { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:473:11 + | +LL | match i = mutex.lock().unwrap().i { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:479:11 + | +LL | match mutex.lock().unwrap().i += 1 { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +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:485:11 + | +LL | match i += mutex.lock().unwrap().i { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try moving the temporary above the match + | +LL ~ i += mutex.lock().unwrap().i; +LL ~ match () { + | + +error: aborting due to 23 previous errors + |