error[E0658]: references in constants may only refer to immutable values
  --> $DIR/issue-17718-const-bad-values.rs:1:34
   |
LL | const C1: &'static mut [usize] = &mut [];
   |                                  ^^^^^^^ constants require immutable values
   |
   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable

error[E0013]: constants cannot refer to statics
  --> $DIR/issue-17718-const-bad-values.rs:5:46
   |
LL | const C2: &'static mut usize = unsafe { &mut S };
   |                                              ^
   |
   = help: consider extracting the value of the `static` to a `const`, and referring to that

error[E0013]: constants cannot refer to statics
  --> $DIR/issue-17718-const-bad-values.rs:5:46
   |
LL | const C2: &'static mut usize = unsafe { &mut S };
   |                                              ^
   |
   = help: consider extracting the value of the `static` to a `const`, and referring to that

error[E0658]: references in constants may only refer to immutable values
  --> $DIR/issue-17718-const-bad-values.rs:5:41
   |
LL | const C2: &'static mut usize = unsafe { &mut S };
   |                                         ^^^^^^ constants require immutable values
   |
   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable

error: aborting due to 4 previous errors

Some errors have detailed explanations: E0013, E0658.
For more information about an error, try `rustc --explain E0013`.