error[E0369]: cannot multiply `&mut Foo` by `&Foo`
  --> $DIR/borrow-suggestion-109352.rs:21:25
   |
LL |     let _ = ref_mut_foo * ref_foo;
   |             ----------- ^ ------- &Foo
   |             |
   |             &mut Foo
   |
   = note: an implementation for `&Foo * &Foo` exists
help: consider reborrowing this side
   |
LL |     let _ = &*ref_mut_foo * ref_foo;
   |             ++

error[E0369]: cannot multiply `&mut Foo` by `&mut Foo`
  --> $DIR/borrow-suggestion-109352.rs:23:25
   |
LL |     let _ = ref_mut_foo * ref_mut_foo;
   |             ----------- ^ ----------- &mut Foo
   |             |
   |             &mut Foo
   |
   = note: an implementation for `&Foo * &Foo` exists
help: consider reborrowing both sides
   |
LL |     let _ = &*ref_mut_foo * &*ref_mut_foo;
   |             ++              ++

error[E0369]: cannot multiply `&mut Foo` by `&Foo`
  --> $DIR/borrow-suggestion-109352.rs:25:25
   |
LL |     let _ = ref_mut_foo * &owned_foo;
   |             ----------- ^ ---------- &Foo
   |             |
   |             &mut Foo
   |
   = note: an implementation for `&Foo * &Foo` exists
help: consider reborrowing this side
   |
LL |     let _ = &*ref_mut_foo * &owned_foo;
   |             ++

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0369`.