1 error[E0596]: cannot borrow immutable `Box` content `*a` as mutable
2 --> $DIR/borrowck-borrow-immut-deref-of-box-as-mut.rs:22:5
4 LL | let a: Box<_> = box A;
5 | - help: make this binding mutable: `mut a`
7 | ^ cannot borrow as mutable
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0596`.