error[E0594]: cannot assign to `**t1`, which is behind a `&` reference
  --> $DIR/borrowck-borrow-mut-base-ptr-in-aliasable-loc.rs:9:5
   |
LL |     **t1 = 22;
   |     ^^^^^^^^^ `t1` is a `&` reference, so the data it refers to cannot be written
   |
help: consider specifying this binding's type
   |
LL |     let t1: &mut &mut isize = t0;
   |           +++++++++++++++++

error[E0502]: cannot borrow `**t0` as immutable because it is also borrowed as mutable
  --> $DIR/borrowck-borrow-mut-base-ptr-in-aliasable-loc.rs:14:21
   |
LL |     let t1 = &mut *t0;
   |              -------- mutable borrow occurs here
LL |     let p: &isize = &**t0;
   |                     ^^^^^ immutable borrow occurs here
LL |     **t1 = 22;
   |     --------- mutable borrow later used here

error[E0596]: cannot borrow `**t0` as mutable, as it is behind a `&` reference
  --> $DIR/borrowck-borrow-mut-base-ptr-in-aliasable-loc.rs:19:26
   |
LL |     let x:  &mut isize = &mut **t0;
   |                          ^^^^^^^^^ `t0` is a `&` reference, so the data it refers to cannot be borrowed as mutable
   |
help: consider changing this to be a mutable reference
   |
LL | fn foo4(t0: &mut  &mut isize) {
   |              +++

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0502, E0594, E0596.
For more information about an error, try `rustc --explain E0502`.