//@ stderr-per-bitwidth //@ ignore-endian-big // ignore-tidy-linelength //@ normalize-stderr-test "╾─*ALLOC[0-9]+(\+[a-z0-9]+)?()?─*╼" -> "╾ALLOC_ID$1╼" #![allow(invalid_value)] #![feature(never_type, rustc_attrs, ptr_metadata, slice_from_ptr_range, const_slice_from_ptr_range)] use std::mem; use std::alloc::Layout; use std::ptr::NonNull; use std::num::NonZero; use std::slice::{from_ptr_range, from_raw_parts}; // # Bad enums and chars #[repr(usize)] #[derive(Copy, Clone)] enum Enum { A = 0, } const BAD_ENUM: Enum = unsafe { mem::transmute(1usize) }; //~^ ERROR is undefined behavior #[repr(usize)] #[derive(Copy, Clone)] enum Enum2 { A = 2, } const BAD_ENUM2: Enum2 = unsafe { mem::transmute(0usize) }; //~^ ERROR is undefined behavior #[derive(Copy, Clone)] enum Never {} // An enum with 3 variants of which some are uninhabited -- so the uninhabited variants *do* // have a discriminant. enum UninhDiscriminant { A, B(!), C, D(Never), } const BAD_UNINHABITED_VARIANT1: UninhDiscriminant = unsafe { mem::transmute(1u8) }; //~^ ERROR is undefined behavior const BAD_UNINHABITED_VARIANT2: UninhDiscriminant = unsafe { mem::transmute(3u8) }; //~^ ERROR is undefined behavior // Invalid enum field content (mostly to test printing of paths for enum tuple // variants and tuples). // Need to create something which does not clash with enum layout optimizations. const BAD_OPTION_CHAR: Option<(char, char)> = Some(('x', unsafe { mem::transmute(!0u32) })); //~^ ERROR is undefined behavior // # Bad pointers and references const NULL_PTR: NonNull = unsafe { mem::transmute(0usize) }; //~^ ERROR it is undefined behavior to use this value const NULL_U8: NonZero = unsafe { mem::transmute(0u8) }; //~^ ERROR it is undefined behavior to use this value const NULL_USIZE: NonZero = unsafe { mem::transmute(0usize) }; //~^ ERROR it is undefined behavior to use this value #[rustc_layout_scalar_valid_range_start(10)] #[rustc_layout_scalar_valid_range_end(30)] struct RestrictedRange1(u32); const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) }; //~^ ERROR it is undefined behavior to use this value #[rustc_layout_scalar_valid_range_start(30)] #[rustc_layout_scalar_valid_range_end(10)] struct RestrictedRange2(u32); const BAD_RANGE2: RestrictedRange2 = unsafe { RestrictedRange2(20) }; //~^ ERROR it is undefined behavior to use this value const NULL_FAT_PTR: NonNull = unsafe { //~^ ERROR it is undefined behavior to use this value let x: &dyn Send = &42; let meta = std::ptr::metadata(x); mem::transmute((0_usize, meta)) }; 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 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 NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) }; //~^ ERROR it is undefined behavior to use this value 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 #[derive(Copy, Clone)] enum Bar {} const BAD_BAD_REF: &Bar = unsafe { mem::transmute(1usize) }; //~^ ERROR it is undefined behavior to use this value /// A newtype wrapper to prevent MIR generation from inserting reborrows that would affect the error /// message. #[repr(transparent)] struct W(T); #[repr(C)] union MaybeUninit { uninit: (), init: T, } trait Trait {} impl Trait for bool {} // custom unsized type struct MyStr(str); // custom unsized type with sized fields struct MySlice(bool, T); type MySliceBool = MySlice<[bool]>; const STR_TOO_LONG: &str = unsafe { mem::transmute((&42u8, 999usize)) }; //~^ ERROR it is undefined behavior to use this value const NESTED_STR_MUCH_TOO_LONG: (&str,) = (unsafe { mem::transmute((&42, usize::MAX)) },); //~^ ERROR it is undefined behavior to use this value const MY_STR_MUCH_TOO_LONG: &MyStr = unsafe { mem::transmute((&42u8, usize::MAX)) }; //~^ ERROR it is undefined behavior to use this value const STR_NO_INIT: &str = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit:: { uninit: () }]) }; //~^ ERROR it is undefined behavior to use this value const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit:: { uninit: () }]) }; //~^ ERROR it is undefined behavior to use this value const MYSTR_NO_INIT_ISSUE83182: &MyStr = unsafe { mem::transmute::<&[_], _>(&[&()]) }; //~^ ERROR: it is undefined behavior to use this value // # slice const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) }; //~^ ERROR it is undefined behavior to use this value const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, isize::MAX)) }; //~^ ERROR it is undefined behavior to use this value // bad slice box: length too big const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999usize)) }; //~^ ERROR it is undefined behavior to use this value // bad data *inside* the slice const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }]; //~^ ERROR it is undefined behavior to use this value //~| constant // bad: sized field is not okay const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]); //~^ ERROR it is undefined behavior to use this value //~| constant // bad: unsized part is not okay const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]); //~^ ERROR it is undefined behavior to use this value //~| constant // bad trait object const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u8))) }; //~^ ERROR it is undefined behavior to use this value //~| expected a vtable // bad trait object const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u64))) }; //~^ ERROR it is undefined behavior to use this value //~| expected a vtable // bad trait object const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, 4usize))) }; //~^ ERROR it is undefined behavior to use this value //~| expected a vtable const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &[&42u8; 8]))) }; //~^ ERROR it is undefined behavior to use this value //~| expected a vtable // bad data *inside* the trait object const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) }; //~^ ERROR it is undefined behavior to use this value //~| expected a boolean const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) }; //~^ ERROR it is undefined behavior to use this value const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) }; //~^ ERROR it is undefined behavior to use this value // Uninhabited types const _: &[!; 1] = unsafe { &*(1_usize as *const [!; 1]) }; //~ ERROR undefined behavior const _: &[!] = unsafe { &*(1_usize as *const [!; 1]) }; //~ ERROR undefined behavior const _: &[!] = unsafe { &*(1_usize as *const [!; 42]) }; //~ ERROR undefined behavior // Reading uninitialized data pub static S4: &[u8] = unsafe { from_raw_parts((&D1) as *const _ as _, 1) }; //~^ ERROR: it is undefined behavior to use this value // Reinterpret pointers as integers (UB in CTFE.) pub static S5: &[u8] = unsafe { from_raw_parts((&D3) as *const _ as _, mem::size_of::<&u32>()) }; //~^ ERROR: it is undefined behavior to use this value // Layout mismatch pub static S6: &[bool] = unsafe { from_raw_parts((&D0) as *const _ as _, 4) }; //~^ ERROR: it is undefined behavior to use this value // Reading padding is not ok pub static S7: &[u16] = unsafe { //~^ ERROR: it is undefined behavior to use this value let ptr = (&D2 as *const Struct as *const u16).add(1); from_raw_parts(ptr, 4) }; pub static R4: &[u8] = unsafe { //~^ ERROR: it is undefined behavior to use this value let ptr = (&D1) as *const mem::MaybeUninit<&u32> as *const u8; from_ptr_range(ptr..ptr.add(1)) }; pub static R5: &[u8] = unsafe { //~^ ERROR: it is undefined behavior to use this value let ptr = &D3 as *const &u32; from_ptr_range(ptr.cast()..ptr.add(1).cast()) }; pub static R6: &[bool] = unsafe { //~^ ERROR: it is undefined behavior to use this value let ptr = &D0 as *const u32 as *const bool; from_ptr_range(ptr..ptr.add(4)) }; const D0: u32 = 0x11111111; // Constant chosen for endianness-independent behavior. const D1: mem::MaybeUninit<&u32> = mem::MaybeUninit::uninit(); const D2: Struct = Struct { a: 1, b: 2, c: 3, d: 4 }; const D3: &u32 = &42; #[repr(C)] struct Struct { a: u8, // _pad: [mem::MaybeUninit; 3] b: u32, c: u16, d: u8, // _pad: [mem::MaybeUninit; 1] } fn main() {}