86 lines
2.0 KiB
Rust
86 lines
2.0 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// As dst-struct.rs, but the unsized field is the only field in the struct.
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struct Fat<T: ?Sized> {
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ptr: T
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}
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// x is a fat pointer
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fn foo(x: &Fat<[isize]>) {
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let y = &x.ptr;
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assert_eq!(x.ptr.len(), 3);
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assert_eq!(y[0], 1);
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assert_eq!(x.ptr[1], 2);
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}
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fn foo2<T:ToBar>(x: &Fat<[T]>) {
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let y = &x.ptr;
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let bar = Bar;
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assert_eq!(x.ptr.len(), 3);
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assert_eq!(y[0].to_bar(), bar);
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assert_eq!(x.ptr[1].to_bar(), bar);
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}
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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struct Bar;
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trait ToBar {
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fn to_bar(&self) -> Bar;
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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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}
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pub fn main() {
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// With a vec of ints.
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let f1 = Fat { ptr: [1, 2, 3] };
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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<[isize]> = f2;
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foo(f3);
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let f4: &Fat<[isize]> = &f1;
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foo(f4);
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let f5: &Fat<[isize]> = &Fat { ptr: [1, 2, 3] };
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foo(f5);
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// With a vec of Bars.
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let bar = Bar;
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let f1 = Fat { ptr: [bar, bar, bar] };
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foo2(&f1);
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let f2 = &f1;
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foo2(f2);
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let f3: &Fat<[Bar]> = f2;
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foo2(f3);
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let f4: &Fat<[Bar]> = &f1;
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foo2(f4);
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let f5: &Fat<[Bar]> = &Fat { ptr: [bar, bar, bar] };
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foo2(f5);
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// Assignment.
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let f5: &mut Fat<[isize]> = &mut Fat { ptr: [1, 2, 3] };
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f5.ptr[1] = 34;
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assert_eq!(f5.ptr[0], 1);
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assert_eq!(f5.ptr[1], 34);
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assert_eq!(f5.ptr[2], 3);
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// Zero size vec.
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let f5: &Fat<[isize]> = &Fat { ptr: [] };
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assert!(f5.ptr.is_empty());
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let f5: &Fat<[Bar]> = &Fat { ptr: [] };
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assert!(f5.ptr.is_empty());
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}
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