114 lines
2.3 KiB
Rust
114 lines
2.3 KiB
Rust
// run-pass
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// revisions: stock precise
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#![feature(const_trait_impl)]
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#![feature(const_mut_refs)]
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#![feature(never_type)]
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#![cfg_attr(precise, feature(const_precise_live_drops))]
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use std::marker::Destruct;
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struct S<'a>(&'a mut u8);
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impl<'a> const Drop for S<'a> {
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fn drop(&mut self) {
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*self.0 += 1;
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}
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}
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const fn a<T: ~const Destruct>(_: T) {}
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const fn b() -> u8 {
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let mut c = 0;
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let _ = S(&mut c);
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a(S(&mut c));
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c
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}
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const C: u8 = b();
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macro_rules! implements_const_drop {
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($($exp:expr),*$(,)?) => {
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$(
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const _: () = a($exp);
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)*
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}
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}
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#[allow(dead_code)]
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mod t {
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pub struct Foo;
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pub enum Bar { A }
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pub fn foo() {}
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pub struct ConstDrop;
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impl const Drop for ConstDrop {
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fn drop(&mut self) {}
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}
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pub struct HasConstDrop(pub ConstDrop);
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pub struct TrivialFields(pub u8, pub i8, pub usize, pub isize);
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#[const_trait]
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pub trait SomeTrait {
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fn foo();
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}
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impl const SomeTrait for () {
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fn foo() {}
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}
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// non-const impl
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impl SomeTrait for i32 {
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fn foo() {}
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}
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pub struct ConstDropWithBound<T: ~const SomeTrait>(pub core::marker::PhantomData<T>);
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impl<T: ~const SomeTrait> const Drop for ConstDropWithBound<T> {
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fn drop(&mut self) {
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T::foo();
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}
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}
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pub struct ConstDropWithNonconstBound<T: SomeTrait>(pub core::marker::PhantomData<T>);
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impl<T: SomeTrait> const Drop for ConstDropWithNonconstBound<T> {
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fn drop(&mut self) {
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// Note: we DON'T use the `T: SomeTrait` bound
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}
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}
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}
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use t::*;
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implements_const_drop! {
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1u8,
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2,
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3.0,
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Foo,
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Bar::A,
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foo,
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ConstDrop,
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HasConstDrop(ConstDrop),
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TrivialFields(1, 2, 3, 4),
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&1,
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&1 as *const i32,
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ConstDropWithBound::<()>,
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ConstDropWithNonconstBound::<i32>,
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Result::<i32, !>::Ok(1),
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}
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fn main() {
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struct HasDropGlue(#[allow(unused_tuple_struct_fields)] Box<u8>);
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struct HasDropImpl;
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impl Drop for HasDropImpl {
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fn drop(&mut self) {
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println!("not trivial drop");
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}
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}
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// These types should pass because ~const in a non-const context should have no effect.
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a(HasDropGlue(Box::new(0)));
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a(HasDropImpl);
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assert_eq!(C, 2);
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}
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