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//@ check-pass
//! Accept lifetime extensions with `Assume::LIFETIMES`.
#![feature(transmutability, core_intrinsics)]
use std::mem::{Assume, TransmuteFrom};
unsafe fn transmute<Src, Dst>(src: Src) -> Dst
where
Dst: TransmuteFrom<Src, { Assume::SAFETY.and(Assume::LIFETIMES) }>,
{
core::intrinsics::transmute_unchecked(src)
}
mod bare {
use super::*;
fn extend_bare<'a>(src: &'a u8) -> &'static u8 {
unsafe { transmute(src) }
}
}
mod nested {
use super::*;
fn extend_nested<'a>(src: &'a &'a u8) -> &'a &'static u8 {
unsafe { transmute(src) }
}
}
mod tuple {
use super::*;
fn extend_unit<'a>(src: (&'a u8,)) -> (&'static u8,) {
unsafe { transmute(src) }
}
fn extend_pair<'a>(src: (&'a u8, u8)) -> (&'static u8, u8) {
unsafe { transmute(src) }
}
}
mod r#struct {
use super::*;
struct Struct<'a>(&'a u8);
fn extend_struct<'a>(src: Struct<'a>) -> Struct<'static> {
unsafe { transmute(src) }
}
}
mod r#enum {
use super::*;
enum Single<'a> {
A(&'a u8),
}
fn extend_single<'a>(src: Single<'a>) -> Single<'static> {
unsafe { transmute(src) }
}
enum Multi<'a> {
A(&'a u8),
B,
C,
}
fn extend_multi<'a>(src: Multi<'a>) -> Multi<'static> {
unsafe { transmute(src) }
}
}
mod hrtb {
use super::*;
fn call_extend_hrtb<'a>(src: &'a u8) -> &'static u8 {
unsafe { extend_hrtb(src) }
}
unsafe fn extend_hrtb<'a>(src: &'a u8) -> &'static u8
where
for<'b> &'b u8: TransmuteFrom<&'a u8, { Assume::LIFETIMES }>,
{
core::intrinsics::transmute_unchecked(src)
}
}
fn main() {}
|
