#![allow(unused)] #![allow(const_err)] // make sure we cannot allow away the errors tested here // normalize-stderr-test "alignment \d+" -> "alignment N" // normalize-stderr-test "offset \d+" -> "offset N" // normalize-stderr-test "allocation \d+" -> "allocation N" // normalize-stderr-test "size \d+" -> "size N" union BoolTransmute { val: u8, bl: bool, } #[repr(C)] #[derive(Copy, Clone)] struct SliceRepr { ptr: *const u8, len: usize, } #[repr(C)] #[derive(Copy, Clone)] struct BadSliceRepr { ptr: *const u8, len: &'static u8, } union SliceTransmute { repr: SliceRepr, bad: BadSliceRepr, slice: &'static [u8], str: &'static str, my_str: &'static MyStr, my_slice: &'static MySliceBool, } #[repr(C)] #[derive(Copy, Clone)] struct DynRepr { ptr: *const u8, vtable: *const u8, } #[repr(C)] #[derive(Copy, Clone)] struct DynRepr2 { ptr: *const u8, vtable: *const u64, } #[repr(C)] #[derive(Copy, Clone)] struct BadDynRepr { ptr: *const u8, vtable: usize, } union DynTransmute { repr: DynRepr, repr2: DynRepr2, bad: BadDynRepr, rust: &'static Trait, } 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]>; // OK const A: &str = unsafe { SliceTransmute { repr: SliceRepr { ptr: &42, len: 1 } }.str}; // bad str const B: &str = unsafe { SliceTransmute { repr: SliceRepr { ptr: &42, len: 999 } }.str}; //~^ ERROR it is undefined behavior to use this value // bad str const C: &str = unsafe { SliceTransmute { bad: BadSliceRepr { ptr: &42, len: &3 } }.str}; //~^ ERROR it is undefined behavior to use this value // bad str in user-defined unsized type const C2: &MyStr = unsafe { SliceTransmute { bad: BadSliceRepr { ptr: &42, len: &3 } }.my_str}; //~^ ERROR it is undefined behavior to use this value // OK const A2: &[u8] = unsafe { SliceTransmute { repr: SliceRepr { ptr: &42, len: 1 } }.slice}; // bad slice const B2: &[u8] = unsafe { SliceTransmute { repr: SliceRepr { ptr: &42, len: 999 } }.slice}; //~^ ERROR it is undefined behavior to use this value // bad slice const C3: &[u8] = unsafe { SliceTransmute { bad: BadSliceRepr { ptr: &42, len: &3 } }.slice}; //~^ ERROR it is undefined behavior to use this value // bad trait object const D: &Trait = unsafe { DynTransmute { repr: DynRepr { ptr: &92, vtable: &3 } }.rust}; //~^ ERROR it is undefined behavior to use this value // bad trait object const E: &Trait = unsafe { DynTransmute { repr2: DynRepr2 { ptr: &92, vtable: &3 } }.rust}; //~^ ERROR it is undefined behavior to use this value // bad trait object const F: &Trait = unsafe { DynTransmute { bad: BadDynRepr { ptr: &92, vtable: 3 } }.rust}; //~^ ERROR it is undefined behavior to use this value // bad data *inside* the trait object const G: &Trait = &unsafe { BoolTransmute { val: 3 }.bl }; //~^ ERROR it is undefined behavior to use this value // bad data *inside* the slice const H: &[bool] = &[unsafe { BoolTransmute { val: 3 }.bl }]; //~^ ERROR it is undefined behavior to use this value // good MySliceBool const I1: &MySliceBool = &MySlice(true, [false]); // bad: sized field is not okay const I2: &MySliceBool = &MySlice(unsafe { BoolTransmute { val: 3 }.bl }, [false]); //~^ ERROR it is undefined behavior to use this value // bad: unsized part is not okay const I3: &MySliceBool = &MySlice(true, [unsafe { BoolTransmute { val: 3 }.bl }]); //~^ ERROR it is undefined behavior to use this value // invalid UTF-8 const J1: &str = unsafe { SliceTransmute { slice: &[0xFF] }.str }; //~^ ERROR it is undefined behavior to use this value // invalid UTF-8 in user-defined str-like const J2: &MyStr = unsafe { SliceTransmute { slice: &[0xFF] }.my_str }; //~^ ERROR it is undefined behavior to use this value fn main() { }