error[E0596]: cannot borrow immutable argument `x` as mutable --> $DIR/borrowck-borrow-overloaded-deref-mut.rs:29:25 | LL | fn deref_mut1(x: Own) { | - help: make this binding mutable: `mut x` LL | let __isize = &mut *x; //~ ERROR cannot borrow | ^ cannot borrow mutably error[E0596]: cannot borrow immutable borrowed content `*x` as mutable --> $DIR/borrowck-borrow-overloaded-deref-mut.rs:41:11 | LL | fn deref_extend_mut1<'a>(x: &'a Own) -> &'a mut isize { | -------------- use `&'a mut Own` here to make mutable LL | &mut **x //~ ERROR cannot borrow | ^^ cannot borrow as mutable error[E0596]: cannot borrow immutable argument `x` as mutable --> $DIR/borrowck-borrow-overloaded-deref-mut.rs:49:6 | LL | fn assign1<'a>(x: Own) { | - help: make this binding mutable: `mut x` LL | *x = 3; //~ ERROR cannot borrow | ^ cannot borrow mutably error[E0596]: cannot borrow immutable borrowed content `*x` as mutable --> $DIR/borrowck-borrow-overloaded-deref-mut.rs:53:6 | LL | fn assign2<'a>(x: &'a Own) { | -------------- use `&'a mut Own` here to make mutable LL | **x = 3; //~ ERROR cannot borrow | ^^ cannot borrow as mutable error: aborting due to 4 previous errors For more information about this error, try `rustc --explain E0596`.