rust/tests/ui/consts/const-eval/transmute-size-mismatch.rs
Scott McMurray 64cce5fc7d Add CastKind::Transmute to MIR
Updates `interpret`, `codegen_ssa`, and `codegen_cranelift` to consume the new cast instead of the intrinsic.

Includes `CastTransmute` for custom MIR building, to be able to test the extra UB.
2023-03-22 15:15:41 -07:00

25 lines
664 B
Rust

#![feature(core_intrinsics)]
#![feature(custom_mir)]
// These cases are statically rejected by `mem::transmute`, so we need custom
// MIR to be able to get to constant evaluation.
use std::intrinsics::mir::*;
#[custom_mir(dialect = "runtime", phase = "initial")]
const unsafe fn mir_transmute<T, U>(x: T) -> U {
mir!{
{
RET = CastTransmute(x);
//~^ ERROR evaluation of constant value failed
//~| ERROR evaluation of constant value failed
Return()
}
}
}
const FROM_BIGGER: u16 = unsafe { mir_transmute(123_i32) };
const FROM_SMALLER: u32 = unsafe { mir_transmute(123_i16) };
fn main() {}