74 lines
1.5 KiB
Rust
74 lines
1.5 KiB
Rust
//@ run-pass
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#![allow(dead_code)]
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use std::rc::Rc;
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use std::ops::Deref;
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#[derive(Copy, Clone)]
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struct DerefWrapper<X, Y> {
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x: X,
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y: Y
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}
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impl<X, Y> DerefWrapper<X, Y> {
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fn get_x(self) -> X {
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self.x
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}
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}
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impl<X, Y> Deref for DerefWrapper<X, Y> {
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type Target = Y;
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fn deref(&self) -> &Y {
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&self.y
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}
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}
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mod priv_test {
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use std::ops::Deref;
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#[derive(Copy, Clone)]
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pub struct DerefWrapperHideX<X, Y> {
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x: X,
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pub y: Y
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}
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impl<X, Y> DerefWrapperHideX<X, Y> {
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pub fn new(x: X, y: Y) -> DerefWrapperHideX<X, Y> {
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DerefWrapperHideX {
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x: x,
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y: y
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}
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}
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}
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impl<X, Y> Deref for DerefWrapperHideX<X, Y> {
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type Target = Y;
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fn deref(&self) -> &Y {
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&self.y
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}
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}
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}
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pub fn main() {
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let nested = DerefWrapper {x: true, y: DerefWrapper {x: 0, y: 1}};
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// Use the first field that you can find.
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assert_eq!(nested.x, true);
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assert_eq!((*nested).x, 0);
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// Same for methods, even though there are multiple
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// candidates (at different nesting levels).
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assert_eq!(nested.get_x(), true);
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assert_eq!((*nested).get_x(), 0);
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// Also go through multiple levels of indirection.
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assert_eq!(Rc::new(nested).x, true);
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let nested_priv = priv_test::DerefWrapperHideX::new(true, DerefWrapper {x: 0, y: 1});
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assert_eq!(nested_priv.x, 0);
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assert_eq!((*nested_priv).x, 0);
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}
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