error[E0277]: `RefCell<isize>` cannot be shared between threads safely
  --> $DIR/issue-7364.rs:4:15
   |
LL | static boxed: Box<RefCell<isize>> = Box::new(RefCell::new(0));
   |               ^^^^^^^^^^^^^^^^^^^ `RefCell<isize>` cannot be shared between threads safely
   |
   = help: the trait `Sync` is not implemented for `RefCell<isize>`, which is required by `Box<RefCell<isize>>: Sync`
   = note: if you want to do aliasing and mutation between multiple threads, use `std::sync::RwLock` instead
   = note: required for `Unique<RefCell<isize>>` to implement `Sync`
note: required because it appears within the type `Box<RefCell<isize>>`
  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
   = note: shared static variables must have a type that implements `Sync`

error[E0015]: cannot call non-const fn `Box::<RefCell<isize>>::new` in statics
  --> $DIR/issue-7364.rs:4:37
   |
LL | static boxed: Box<RefCell<isize>> = Box::new(RefCell::new(0));
   |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: calls in statics are limited to constant functions, tuple structs and tuple variants
   = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0015, E0277.
For more information about an error, try `rustc --explain E0015`.