//@ compile-flags: -Zunleash-the-miri-inside-of-you //@ normalize-stderr-test "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)" //@ normalize-stderr-test "([0-9a-f][0-9a-f] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?()?─*╼ )+ *│.*" -> "HEX_DUMP" #![allow(invalid_reference_casting, static_mut_refs)] #![deny(const_eval_mutable_ptr_in_final_value)] use std::cell::UnsafeCell; use std::sync::atomic::*; // this test ensures that our mutability story is sound struct Meh { x: &'static UnsafeCell, } unsafe impl Sync for Meh {} // the following will never be ok! no interior mut behind consts, because // all allocs interned here will be marked immutable. const MUH: Meh = Meh { //~^ ERROR encountered mutable pointer in final value of constant //~| WARNING this was previously accepted by the compiler //~| ERROR: it is undefined behavior to use this value x: &UnsafeCell::new(42), }; struct Synced { x: UnsafeCell, } unsafe impl Sync for Synced {} // Make sure we also catch this behind a type-erased `dyn Trait` reference. const SNEAKY: &dyn Sync = &Synced { x: UnsafeCell::new(42) }; //~^ ERROR: mutable pointer in final value //~| WARNING this was previously accepted by the compiler //~| ERROR it is undefined behavior to use this value // Make sure we also catch mutable references in values that shouldn't have them. static mut FOO: i32 = 0; const SUBTLE: &mut i32 = unsafe { &mut FOO }; //~^ ERROR: it is undefined behavior to use this value //~| static const BLUNT: &mut i32 = &mut 42; //~^ ERROR: mutable pointer in final value //~| WARNING this was previously accepted by the compiler //~| ERROR it is undefined behavior to use this value // Check for mutable references to read-only memory. static READONLY: i32 = 0; static mut MUT_TO_READONLY: &mut i32 = unsafe { &mut *(&READONLY as *const _ as *mut _) }; //~^ ERROR: it is undefined behavior to use this value //~| pointing to read-only memory // Check for consts pointing to mutable memory. // These are fine as long as they are not being read. static mut MUTABLE: i32 = 42; const POINTS_TO_MUTABLE1: &i32 = unsafe { &MUTABLE }; //~ERROR: undefined behavior //~| encountered reference to mutable memory const READS_FROM_MUTABLE: i32 = *POINTS_TO_MUTABLE1; static mut MUTABLE_REF: &mut i32 = &mut 42; const POINTS_TO_MUTABLE2: &i32 = unsafe { &*MUTABLE_REF }; //~^ ERROR: evaluation of constant value failed //~| accesses mutable global memory const POINTS_TO_MUTABLE_INNER: *const i32 = &mut 42 as *mut _ as *const _; //~^ ERROR: mutable pointer in final value //~| WARNING this was previously accepted by the compiler const POINTS_TO_MUTABLE_INNER2: *const i32 = &mut 42 as *const _; //~^ ERROR: mutable pointer in final value //~| WARNING this was previously accepted by the compiler const INTERIOR_MUTABLE_BEHIND_RAW: *mut i32 = &UnsafeCell::new(42) as *const _ as *mut _; //~^ ERROR: mutable pointer in final value //~| WARNING this was previously accepted by the compiler struct SyncPtr { x: *const T, } unsafe impl Sync for SyncPtr {} // These pass the lifetime checks because of the "tail expression" / "outer scope" rule. // (This relies on `SyncPtr` being a curly brace struct.) // However, we intern the inner memory as read-only, so this must be rejected. // (Also see `static-no-inner-mut` for similar tests on `static`.) const RAW_SYNC: SyncPtr = SyncPtr { x: &AtomicI32::new(42) }; //~^ ERROR mutable pointer in final value //~| WARNING this was previously accepted by the compiler const RAW_MUT_CAST: SyncPtr = SyncPtr { x: &mut 42 as *mut _ as *const _ }; //~^ ERROR mutable pointer in final value //~| WARNING this was previously accepted by the compiler const RAW_MUT_COERCE: SyncPtr = SyncPtr { x: &mut 0 }; //~^ ERROR mutable pointer in final value //~| WARNING this was previously accepted by the compiler fn main() { unsafe { *MUH.x.get() = 99; } }