static static_x : i32 = 1; static mut static_x_mut : i32 = 1; fn main() { let x = 1; let mut x_mut = 1; { // borrow of local let _y1 = &mut x; //~ ERROR [E0596] let _y2 = &mut x_mut; // No error } { // borrow of static let _y1 = &mut static_x; //~ ERROR [E0596] unsafe { let _y2 = &mut static_x_mut; } // No error } { // borrow of deref to box let box_x = Box::new(1); let mut box_x_mut = Box::new(1); let _y1 = &mut *box_x; //~ ERROR [E0596] let _y2 = &mut *box_x_mut; // No error } { // borrow of deref to reference let ref_x = &x; let ref_x_mut = &mut x_mut; let _y1 = &mut *ref_x; //~ ERROR [E0596] let _y2 = &mut *ref_x_mut; // No error } { // borrow of deref to pointer let ptr_x : *const _ = &x; let ptr_mut_x : *mut _ = &mut x_mut; unsafe { let _y1 = &mut *ptr_x; //~ ERROR [E0596] let _y2 = &mut *ptr_mut_x; // No error } } { // borrowing mutably through an immutable reference struct Foo<'a> { f: &'a mut i32, g: &'a i32 }; let mut foo = Foo { f: &mut x_mut, g: &x }; let foo_ref = &foo; let _y = &mut *foo_ref.f; //~ ERROR [E0596] } }