Enum ExplicitSelf

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

Variants

ByValue

ByReference(Region<'tcx>, Mutability)

ByRawPointer(Mutability)

ByBox

Other

Implementations

impl<'tcx> ExplicitSelf<'tcx>

pub fn determine<P>(self_arg_ty: Ty<'tcx>, is_self_ty: P) -> ExplicitSelf<'tcx>

where P: Fn(Ty<'tcx>) -> bool,

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 dyn-incompatible.

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
}

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