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Update/improve documentation of ExpliciSelf

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This commit is contained in:
Michael Hewson 2017-11-07 05:33:54 -05:00
parent 6fd215647d
commit 0d739b5b97
1 changed files with 14 additions and 11 deletions
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25
src/librustc_typeck/astconv.rs
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@ -1413,23 +1413,26 @@ pub enum ExplicitSelf<'tcx> {
}
impl<'tcx> ExplicitSelf<'tcx> {
/// We wish to (for now) categorize an explicit self
/// declaration like `self: SomeType` into either `self`,
/// `&self`, `&mut self`, or `Box<self>`. We do this here
/// by some simple pattern matching. A more precise check
/// is done later in `check_method_receiver()`.
/// Categorizes an explicit self declaration like `self: SomeType`
/// into either `self`, `&self`, `&mut self`, `Box<self>`, or
/// `Other` (meaning the arbitrary_self_types feature is used).
/// We do this here via a combination of pattern matching and
/// `can_eq`. A more precise check is done in `check_method_receiver()`.
///
/// Examples:
///
/// ```
/// impl Foo for &T {
/// impl<'a> Foo for &'a T {
/// // Legal declarations:
/// fn method1(self: &&T); // ExplicitSelf::ByReference
/// fn method2(self: &T); // ExplicitSelf::ByValue
/// fn method3(self: Box<&T>); // ExplicitSelf::ByBox
/// 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 later by `check_method_receiver`:
/// fn method_err1(self: &mut T); // ExplicitSelf::ByReference
/// // 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
/// }
/// ```
///