Enum BorrowKind

pub enum BorrowKind {
    Shared,
    Fake(FakeBorrowKind),
    Mut {
        kind: MutBorrowKind,
    },
}

Variants

Shared

Data must be immutable and is aliasable.

Fake(FakeBorrowKind)

An immutable, aliasable borrow that is discarded after borrow-checking. Can behave either like a normal shared borrow or like a special shallow borrow (see FakeBorrowKind).

This is used when lowering index expressions and matches. This is used to prevent code like the following from compiling:

let mut x: &[_] = &[[0, 1]];
let y: &[_] = &[];
let _ = x[0][{x = y; 1}];

let mut x = &Some(0);
match *x {
    None => (),
    Some(_) if { x = &None; false } => (),
    Some(_) => (),
}

We can also report errors with this kind of borrow differently.

Mut

Data is mutable and not aliasable.

Fields

kind: MutBorrowKind