Enum rustc_middle::ty::util::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 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
}