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// 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 static_u8() -> &'static u8 {
&8
}
unsafe fn ref_to_mut() {
let num = &3i32;
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 = &mut *std::ptr::from_ref(num).cast_mut();
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *std::ptr::from_ref({ num }).cast_mut();
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *{ std::ptr::from_ref(num) }.cast_mut();
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *(std::ptr::from_ref({ num }) as *mut i32);
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *(num as *const i32).cast::<i32>().cast_mut();
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *(num as *const i32).cast::<i32>().cast_mut().cast_const().cast_mut();
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *(std::ptr::from_ref(static_u8()) as *mut i32);
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *std::mem::transmute::<_, *mut i32>(num);
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let deferred = num as *const i32 as *mut i32;
let _num = &mut *deferred;
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let deferred = (std::ptr::from_ref(num) as *const i32 as *const i32).cast_mut() as *mut i32;
let _num = &mut *deferred;
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
let _num = &mut *(num as *const _ as usize as *mut i32);
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
unsafe fn generic_ref_cast_mut<T>(this: &T) -> &mut T {
&mut *((this as *const _) as *mut _)
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
}
}
unsafe fn assign_to_ref() {
let s = String::from("Hello");
let a = &s;
let num = &3i32;
*(a as *const _ as *mut _) = String::from("Replaced");
//~^ ERROR assigning to `&T` is undefined behavior
*(a as *const _ as *mut String) += " world";
//~^ ERROR assigning to `&T` is undefined behavior
*std::ptr::from_ref(num).cast_mut() += 1;
//~^ ERROR assigning to `&T` is undefined behavior
*std::ptr::from_ref({ num }).cast_mut() += 1;
//~^ ERROR assigning to `&T` is undefined behavior
*{ std::ptr::from_ref(num) }.cast_mut() += 1;
//~^ ERROR assigning to `&T` is undefined behavior
*(std::ptr::from_ref({ num }) as *mut i32) += 1;
//~^ ERROR assigning to `&T` is undefined behavior
*std::mem::transmute::<_, *mut i32>(num) += 1;
//~^ ERROR assigning to `&T` is undefined behavior
let value = num as *const i32 as *mut i32;
*value = 1;
//~^ ERROR assigning to `&T` is undefined behavior
*(num as *const i32).cast::<i32>().cast_mut() = 2;
//~^ ERROR assigning to `&T` is undefined behavior
*(num as *const _ as usize as *mut i32) = 2;
//~^ ERROR assigning to `&T` is undefined behavior
unsafe fn generic_assign_to_ref<T>(this: &T, a: T) {
*(this as *const _ as *mut _) = a;
//~^ ERROR assigning to `&T` is undefined behavior
}
}
unsafe fn no_warn() {
let num = &3i32;
let mut_num = &mut 3i32;
let a = &String::from("ffi");
*(num as *const i32 as *mut i32);
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;
}
fn main() {}
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