51 lines
1.9 KiB
Rust
51 lines
1.9 KiB
Rust
|
// check-fail
|
||
|
|
|
||
|
|
#![feature(ptr_from_ref)]
|
||
|
|
|
||
|
|
extern "C" {
|
||
|
|
// N.B., mutability can be easily incorrect in FFI calls -- as
|
||
|
|
// in C, the default is mutable pointers.
|
||
|
|
fn ffi(c: *mut u8);
|
||
|
|
fn int_ffi(c: *mut i32);
|
||
|
|
}
|
||
|
|
|
||
|
|
fn main() {
|
||
|
|
let s = String::from("Hello");
|
||
|
|
let a = &s;
|
||
|
|
unsafe {
|
||
|
|
let num = &3i32;
|
||
|
|
let mut_num = &mut 3i32;
|
||
|
|
|
||
|
|
(*(a as *const _ as *mut String)).push_str(" world");
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
*(a as *const _ as *mut _) = String::from("Replaced");
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
*(a as *const _ as *mut String) += " world";
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
let _num = &mut *(num as *const i32 as *mut i32);
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
let _num = &mut *(num as *const i32).cast_mut();
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
let _num = *{ num as *const i32 }.cast_mut();
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
*std::ptr::from_ref(num).cast_mut() += 1;
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
*std::ptr::from_ref({ num }).cast_mut() += 1;
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
*{ std::ptr::from_ref(num) }.cast_mut() += 1;
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
*(std::ptr::from_ref({ num }) as *mut i32) += 1;
|
||
|
|
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
|
||
|
|
|
||
|
|
// Shouldn't be warned against
|
||
|
|
println!("{}", *(num as *const _ as *const i16));
|
||
|
|
println!("{}", *(mut_num as *mut _ as *mut i16));
|
||
|
|
ffi(a.as_ptr() as *mut _);
|
||
|
|
int_ffi(num as *const _ as *mut _);
|
||
|
|
int_ffi(&3 as *const _ as *mut _);
|
||
|
|
let mut value = 3;
|
||
|
|
let value: *const i32 = &mut value;
|
||
|
|
*(value as *const i16 as *mut i16) = 42;
|
||
|
|
}
|
||
|
|
}
|