pub enum ExplicitSelf<'tcx> {
    ByValue,
    ByReference(Region<'tcx>, Mutability),
    ByRawPointer(Mutability),
    ByBox,
    Other,
}

Variants

ByValue

ByReference(Region<'tcx>, Mutability)

ByRawPointer(Mutability)

ByBox

Other

Implementations

Categorizes an explicit self declaration like self: SomeType into either self, &self, &mut self, Box<self>, or Other. This is mainly used to require the arbitrary_self_types feature in the case of Other, to improve error messages in the common cases, and to make Other non-object-safe.

Examples:

impl<'a> Foo for &'a T {
    // Legal declarations:
    fn method1(self: &&'a T); // ExplicitSelf::ByReference
    fn method2(self: &'a T); // ExplicitSelf::ByValue
    fn method3(self: Box<&'a T>); // ExplicitSelf::ByBox
    fn method4(self: Rc<&'a T>); // ExplicitSelf::Other

    // Invalid cases will be caught by `check_method_receiver`:
    fn method_err1(self: &'a mut T); // ExplicitSelf::Other
    fn method_err2(self: &'static T) // ExplicitSelf::ByValue
    fn method_err3(self: &&T) // ExplicitSelf::ByReference
}

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes

Size for each variant:

  • ByValue: 0 bytes
  • ByReference: 15 bytes
  • ByRawPointer: 1 byte
  • ByBox: 0 bytes
  • Other: 0 bytes