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// Test that we can handle unsized types with an extern type tail part.
// Regression test for issue #91827.
#![feature(extern_types)]
use std::ptr::addr_of;
extern "C" {
type Opaque;
}
struct Newtype(Opaque);
struct S {
i: i32,
j: i32,
a: Newtype,
}
const NEWTYPE: () = unsafe {
let buf = [0i32; 4];
let x: &Newtype = &*(&buf as *const _ as *const Newtype);
// Projecting to the newtype works, because it is always at offset 0.
let field = &x.0;
};
const OFFSET: () = unsafe {
let buf = [0i32; 4];
let x: &S = &*(&buf as *const _ as *const S);
// Accessing sized fields is perfectly fine, even at non-zero offsets.
let field = &x.i;
let field = &x.j;
// This needs to compute the field offset, but we don't know the type's alignment, so this
// fails.
let field = &x.a;
//~^ ERROR: evaluation of constant value failed
//~| does not have a known offset
};
fn main() {}
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