#![feature(const_mut_refs)] #![feature(raw_ref_op)] // This file checks that our dynamic checks catch things that the static checks miss. // We do not have static checks for these, because we do not look into function bodies. // We treat all functions as not returning a mutable reference, because there is no way to // do that without causing the borrow checker to complain (see the B4/helper test in // mut_ref_in_final.rs). const fn helper() -> Option<&'static mut i32> { unsafe { // Undefined behaviour (integer as pointer), who doesn't love tests like this. // This code never gets executed, because the static checks fail before that. Some(&mut *(42 as *mut i32)) //~ ERROR evaluation of constant value failed //~| 0x2a[noalloc] is a dangling pointer } } // The error is an evaluation error and not a validation error, so the error is reported // directly at the site where it occurs. const A: Option<&mut i32> = helper(); const fn helper2() -> Option<&'static mut i32> { unsafe { // Undefined behaviour (dangling pointer), who doesn't love tests like this. // This code never gets executed, because the static checks fail before that. Some(&mut *(&mut 42 as *mut i32)) } } const B: Option<&mut i32> = helper2(); //~ ERROR encountered dangling pointer in final constant fn main() {}