// ignore-tidy-linelength // Strip out raw byte dumps to make comparison platform-independent: //@ normalize-stderr-test: "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)" //@ normalize-stderr-test: "([0-9a-f][0-9a-f] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?()?─*╼ )+ *│.*" -> "HEX_DUMP" #![allow(invalid_value)] use std::mem; #[repr(C)] union MaybeUninit { uninit: (), init: T, } const UNALIGNED: &u16 = unsafe { mem::transmute(&[0u8; 4]) }; //~^ ERROR it is undefined behavior to use this value //~| constructing invalid value: encountered an unaligned reference (required 2 byte alignment but found 1) const UNALIGNED_BOX: Box = unsafe { mem::transmute(&[0u8; 4]) }; //~^ ERROR it is undefined behavior to use this value //~| constructing invalid value: encountered an unaligned box (required 2 byte alignment but found 1) const NULL: &u16 = unsafe { mem::transmute(0usize) }; //~^ ERROR it is undefined behavior to use this value const NULL_BOX: Box = unsafe { mem::transmute(0usize) }; //~^ ERROR it is undefined behavior to use this value // It is very important that we reject this: We do promote `&(4 * REF_AS_USIZE)`, // but that would fail to compile; so we ended up breaking user code that would // have worked fine had we not promoted. const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) }; //~^ ERROR evaluation of constant value failed const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }]; //~^ ERROR evaluation of constant value failed const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) }; //~^ ERROR evaluation of constant value failed const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) }; //~^ ERROR it is undefined behavior to use this value const USIZE_AS_BOX: Box = unsafe { mem::transmute(1337usize) }; //~^ ERROR it is undefined behavior to use this value const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init }; //~^ ERROR evaluation of constant value failed //~| uninitialized const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) }; //~^ ERROR it is undefined behavior to use this value const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init }; //~^ ERROR evaluation of constant value failed //~| uninitialized const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) }; //~^ ERROR it is undefined behavior to use this value const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) }; //~^ ERROR it is undefined behavior to use this value const UNALIGNED_READ: () = unsafe { let x = &[0u8; 4]; let ptr = x.as_ptr().cast::(); ptr.read(); //~ inside `UNALIGNED_READ` }; fn main() {}