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//@ run-pass
//@ needs-unwind
#![allow(dead_code, unreachable_code)]
use std::cell::RefCell;
use std::rc::Rc;
use std::panic::{self, AssertUnwindSafe, UnwindSafe};
// This struct is used to record the order in which elements are dropped
struct PushOnDrop {
vec: Rc<RefCell<Vec<u32>>>,
val: u32
}
impl PushOnDrop {
fn new(val: u32, vec: Rc<RefCell<Vec<u32>>>) -> PushOnDrop {
PushOnDrop { vec, val }
}
}
impl Drop for PushOnDrop {
fn drop(&mut self) {
self.vec.borrow_mut().push(self.val)
}
}
impl UnwindSafe for PushOnDrop { }
// Structs
struct TestStruct {
x: PushOnDrop,
y: PushOnDrop,
z: PushOnDrop
}
// Tuple structs
struct TestTupleStruct(PushOnDrop, PushOnDrop, PushOnDrop);
// Enum variants
enum TestEnum {
Tuple(PushOnDrop, PushOnDrop, PushOnDrop),
Struct { x: PushOnDrop, y: PushOnDrop, z: PushOnDrop }
}
fn test_drop_tuple() {
// Tuple fields are dropped in the same order they are declared
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let test_tuple = (PushOnDrop::new(1, dropped_fields.clone()),
PushOnDrop::new(2, dropped_fields.clone()));
drop(test_tuple);
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
// Panic during construction means that fields are treated as local variables
// Therefore they are dropped in reverse order of initialization
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
(PushOnDrop::new(2, cloned.clone()),
PushOnDrop::new(1, cloned.clone()),
panic!("this panic is caught :D"));
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
}
fn test_drop_struct() {
// Struct fields are dropped in the same order they are declared
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let test_struct = TestStruct {
x: PushOnDrop::new(1, dropped_fields.clone()),
y: PushOnDrop::new(2, dropped_fields.clone()),
z: PushOnDrop::new(3, dropped_fields.clone()),
};
drop(test_struct);
assert_eq!(*dropped_fields.borrow(), &[1, 2, 3]);
// The same holds for tuple structs
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let test_tuple_struct = TestTupleStruct(PushOnDrop::new(1, dropped_fields.clone()),
PushOnDrop::new(2, dropped_fields.clone()),
PushOnDrop::new(3, dropped_fields.clone()));
drop(test_tuple_struct);
assert_eq!(*dropped_fields.borrow(), &[1, 2, 3]);
// Panic during struct construction means that fields are treated as local variables
// Therefore they are dropped in reverse order of initialization
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
TestStruct {
x: PushOnDrop::new(2, cloned.clone()),
y: PushOnDrop::new(1, cloned.clone()),
z: panic!("this panic is caught :D")
};
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
// Test with different initialization order
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
TestStruct {
y: PushOnDrop::new(2, cloned.clone()),
x: PushOnDrop::new(1, cloned.clone()),
z: panic!("this panic is caught :D")
};
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
// The same holds for tuple structs
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
TestTupleStruct(PushOnDrop::new(2, cloned.clone()),
PushOnDrop::new(1, cloned.clone()),
panic!("this panic is caught :D"));
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
}
fn test_drop_enum() {
// Enum variants are dropped in the same order they are declared
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let test_struct_enum = TestEnum::Struct {
x: PushOnDrop::new(1, dropped_fields.clone()),
y: PushOnDrop::new(2, dropped_fields.clone()),
z: PushOnDrop::new(3, dropped_fields.clone())
};
drop(test_struct_enum);
assert_eq!(*dropped_fields.borrow(), &[1, 2, 3]);
// The same holds for tuple enum variants
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let test_tuple_enum = TestEnum::Tuple(PushOnDrop::new(1, dropped_fields.clone()),
PushOnDrop::new(2, dropped_fields.clone()),
PushOnDrop::new(3, dropped_fields.clone()));
drop(test_tuple_enum);
assert_eq!(*dropped_fields.borrow(), &[1, 2, 3]);
// Panic during enum construction means that fields are treated as local variables
// Therefore they are dropped in reverse order of initialization
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
TestEnum::Struct {
x: PushOnDrop::new(2, cloned.clone()),
y: PushOnDrop::new(1, cloned.clone()),
z: panic!("this panic is caught :D")
};
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
// Test with different initialization order
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
TestEnum::Struct {
y: PushOnDrop::new(2, cloned.clone()),
x: PushOnDrop::new(1, cloned.clone()),
z: panic!("this panic is caught :D")
};
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
// The same holds for tuple enum variants
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
TestEnum::Tuple(PushOnDrop::new(2, cloned.clone()),
PushOnDrop::new(1, cloned.clone()),
panic!("this panic is caught :D"));
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
}
fn test_drop_list() {
// Elements in a Vec are dropped in the same order they are pushed
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let xs = vec![PushOnDrop::new(1, dropped_fields.clone()),
PushOnDrop::new(2, dropped_fields.clone()),
PushOnDrop::new(3, dropped_fields.clone())];
drop(xs);
assert_eq!(*dropped_fields.borrow(), &[1, 2, 3]);
// The same holds for arrays
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let xs = [PushOnDrop::new(1, dropped_fields.clone()),
PushOnDrop::new(2, dropped_fields.clone()),
PushOnDrop::new(3, dropped_fields.clone())];
drop(xs);
assert_eq!(*dropped_fields.borrow(), &[1, 2, 3]);
// Panic during vec construction means that fields are treated as local variables
// Therefore they are dropped in reverse order of initialization
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
vec![
PushOnDrop::new(2, cloned.clone()),
PushOnDrop::new(1, cloned.clone()),
panic!("this panic is caught :D")
];
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
// The same holds for arrays
let dropped_fields = Rc::new(RefCell::new(Vec::new()));
let cloned = AssertUnwindSafe(dropped_fields.clone());
panic::catch_unwind(|| {
[
PushOnDrop::new(2, cloned.clone()),
PushOnDrop::new(1, cloned.clone()),
panic!("this panic is caught :D")
];
}).err().unwrap();
assert_eq!(*dropped_fields.borrow(), &[1, 2]);
}
fn main() {
test_drop_tuple();
test_drop_struct();
test_drop_enum();
test_drop_list();
}
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