mirror of https://github.com/rust-lang/rust
103 lines
2.0 KiB
Rust
103 lines
2.0 KiB
Rust
//@ run-pass
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#![allow(type_alias_bounds)]
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#![allow(unused_features)]
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#![feature(unsized_tuple_coercion)]
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type Fat<T: ?Sized> = (isize, &'static str, T);
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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struct Bar;
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#[derive(Copy, Clone, PartialEq, Eq)]
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struct Bar1 {
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f: isize
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}
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trait ToBar {
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fn to_bar(&self) -> Bar;
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fn to_val(&self) -> isize;
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}
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impl ToBar for Bar {
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fn to_bar(&self) -> Bar {
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*self
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}
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fn to_val(&self) -> isize {
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0
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}
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}
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impl ToBar for Bar1 {
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fn to_bar(&self) -> Bar {
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Bar
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}
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fn to_val(&self) -> isize {
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self.f
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}
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}
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// x is a fat pointer
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fn foo(x: &Fat<dyn ToBar>) {
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assert_eq!(x.0, 5);
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assert_eq!(x.1, "some str");
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assert_eq!(x.2.to_bar(), Bar);
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assert_eq!(x.2.to_val(), 42);
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let y = &x.2;
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assert_eq!(y.to_bar(), Bar);
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assert_eq!(y.to_val(), 42);
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}
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fn bar(x: &dyn ToBar) {
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assert_eq!(x.to_bar(), Bar);
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assert_eq!(x.to_val(), 42);
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}
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fn baz(x: &Fat<Fat<dyn ToBar>>) {
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assert_eq!(x.0, 5);
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assert_eq!(x.1, "some str");
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assert_eq!((x.2).0, 8);
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assert_eq!((x.2).1, "deep str");
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assert_eq!((x.2).2.to_bar(), Bar);
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assert_eq!((x.2).2.to_val(), 42);
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let y = &(x.2).2;
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assert_eq!(y.to_bar(), Bar);
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assert_eq!(y.to_val(), 42);
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}
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pub fn main() {
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let f1 = (5, "some str", Bar1 {f :42});
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foo(&f1);
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let f2 = &f1;
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foo(f2);
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let f3: &Fat<dyn ToBar> = f2;
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foo(f3);
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let f4: &Fat<dyn ToBar> = &f1;
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foo(f4);
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let f5: &Fat<dyn ToBar> = &(5, "some str", Bar1 {f :42});
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foo(f5);
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// Zero size object.
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let f6: &Fat<dyn ToBar> = &(5, "some str", Bar);
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assert_eq!(f6.2.to_bar(), Bar);
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// &*
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//
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let f7: Box<dyn ToBar> = Box::new(Bar1 {f :42});
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bar(&*f7);
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// Deep nesting
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let f1 = (5, "some str", (8, "deep str", Bar1 {f :42}));
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baz(&f1);
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let f2 = &f1;
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baz(f2);
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let f3: &Fat<Fat<dyn ToBar>> = f2;
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baz(f3);
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let f4: &Fat<Fat<dyn ToBar>> = &f1;
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baz(f4);
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let f5: &Fat<Fat<dyn ToBar>> = &(5, "some str", (8, "deep str", Bar1 {f :42}));
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baz(f5);
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}
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