rust/tests/ui/mir/enum/numbered_variants_ok.rs

//@ run-pass
//@ compile-flags: -C debug-assertions

#[allow(dead_code)]
enum Foo {
    A,
    B,
}

fn main() {
    let _val: Foo = unsafe { std::mem::transmute::<u8, Foo>(0) };
    let _val: Foo = unsafe { std::mem::transmute::<u8, Foo>(1) };
}
Insert checks for enum discriminants when debug assertions are enabled Similar to the existing nullpointer and alignment checks, this checks for valid enum discriminants on creation of enums through unsafe transmutes. Essentially this sanitizes patterns like the following: ```rust let val: MyEnum = unsafe { std::mem::transmute<u32, MyEnum>(42) }; ``` An extension of this check will be done in a follow-up that explicitly sanitizes for extern enum values that come into Rust from e.g. C/C++. This check is similar to Miri's capabilities of checking for valid construction of enum values. This PR is inspired by saethlin@'s PR https://github.com/rust-lang/rust/pull/104862. Thank you so much for keeping this code up and the detailed comments! I also pair-programmed large parts of this together with vabr-g@. 2025-05-15 19:09:13 +00:00			`//@ run-pass`
			`//@ compile-flags: -C debug-assertions`

			`#[allow(dead_code)]`
			`enum Foo {`
			`A,`
			`B,`
			`}`

			`fn main() {`
			`let _val: Foo = unsafe { std::mem::transmute::<u8, Foo>(0) };`
			`let _val: Foo = unsafe { std::mem::transmute::<u8, Foo>(1) };`
			`}`