19f6c17df4
This makes the following API stable in const contexts:
impl<T> Option<T> {
pub const fn as_mut(&mut self) -> Option<&mut T>;
pub const fn expect(self, msg: &str) -> T;
pub const fn unwrap(self) -> T;
pub const unsafe fn unwrap_unchecked(self) -> T;
pub const fn take(&mut self) -> Option<T>;
pub const fn replace(&mut self, value: T) -> Option<T>;
}
impl<T> Option<&T> {
pub const fn copied(self) -> Option<T>
where T: Copy;
}
impl<T> Option<&mut T> {
pub const fn copied(self) -> Option<T>
where T: Copy;
}
impl<T, E> Option<Result<T, E>> {
pub const fn transpose(self) -> Result<Option<T>, E>
}
impl<T> Option<Option<T>> {
pub const fn flatten(self) -> Option<T>;
}
The following functions make use of the unstable
`const_precise_live_drops` feature:
- `expect`
- `unwrap`
- `unwrap_unchecked`
- `transpose`
- `flatten`
Fixes: <https://github.com/rust-lang/rust/issues/67441>
18 lines
467 B
Rust
18 lines
467 B
Rust
//@ check-fail
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// Verify that panicking `const_option` methods do the correct thing
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const FOO: i32 = Some(42i32).unwrap();
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const BAR: i32 = Option::<i32>::None.unwrap();
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//~^ ERROR: evaluation of constant value failed
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//~| NOTE: the evaluated program panicked
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const BAZ: i32 = Option::<i32>::None.expect("absolutely not!");
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//~^ ERROR: evaluation of constant value failed
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//~| NOTE: absolutely not!
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fn main() {
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println!("{}", FOO);
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println!("{}", BAR);
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}
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