Enum BorrowKind

pub enum BorrowKind {
    Shared,
    Shallow,
    Mut {
        kind: MutBorrowKind,
    },
}

Variants

Shared

Data must be immutable and is aliasable.

Shallow

The immediately borrowed place must be immutable, but projections from it don’t need to be. For example, a shallow borrow of a.b doesn’t conflict with a mutable borrow of a.b.c.

This is used when lowering matches: when matching on a place we want to ensure that place have the same value from the start of the match until an arm is selected. This prevents this code from compiling:

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

This can’t be a shared borrow because mutably borrowing (*x as Some).0 should not prevent if let None = x { ... }, for example, because the mutating (*x as Some).0 can’t affect the discriminant of x. We can also report errors with this kind of borrow differently.

Mut

Data is mutable and not aliasable.

Fields

kind: MutBorrowKind

Trait Implementations

impl Clone for BorrowKind

fn clone(&self) -> BorrowKind

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BorrowKind

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Ord for BorrowKind

fn cmp(&self, other: &BorrowKind) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for BorrowKind

fn eq(&self, other: &BorrowKind) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for BorrowKind

fn partial_cmp(&self, other: &BorrowKind) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for BorrowKind

impl Eq for BorrowKind

impl StructuralPartialEq for BorrowKind