error: any use of this value will cause an error
  --> $DIR/mutable_const.rs:18:9
   |
LL | / const MUTATING_BEHIND_RAW: () = {
LL | |     // Test that `MUTABLE_BEHIND_RAW` is actually immutable, by doing this at const time.
LL | |     unsafe {
LL | |         *MUTABLE_BEHIND_RAW = 99
   | |         ^^^^^^^^^^^^^^^^^^^^^^^^ writing to allocN which is read-only
...  |
LL | |     }
LL | | };
   | |__-
   |
note: the lint level is defined here
  --> $DIR/mutable_const.rs:4:9
   |
LL | #![deny(const_err)] // The `allow` variant is tested by `mutable_const2`.
   |         ^^^^^^^^^

warning: skipping const checks
   |
help: skipping check that does not even have a feature gate
  --> $DIR/mutable_const.rs:13:38
   |
LL | const MUTABLE_BEHIND_RAW: *mut i32 = &UnsafeCell::new(42) as *const _ as *mut _;
   |                                      ^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_raw_ptr_deref` feature
  --> $DIR/mutable_const.rs:18:9
   |
LL |         *MUTABLE_BEHIND_RAW = 99
   |         ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_mut_refs` feature
  --> $DIR/mutable_const.rs:18:9
   |
LL |         *MUTABLE_BEHIND_RAW = 99
   |         ^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error; 1 warning emitted