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Add test using early-bound lifetimes in trait generic parameters.
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pnkfelix committed Mar 26, 2014
1 parent ab8e026 commit 0cbb1ce
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135 changes: 135 additions & 0 deletions src/test/run-pass/regions-early-bound-trait-param.rs
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

// Tests that you can use an early-bound lifetime parameter as
// on of the generic parameters in a trait.

trait Trait<'a> {
fn long(&'a self) -> int;
fn short<'b>(&'b self) -> int;
}

fn poly_invoke<'c, T: Trait<'c>>(x: &'c T) -> (int, int) {
let l = x.long();
let s = x.short();
(l,s)
}

fn object_invoke1<'d>(x: &'d Trait<'d>) -> (int, int) {
let l = x.long();
let s = x.short();
(l,s)
}

struct Struct1<'e> {
f: &'e Trait<'e>
}

fn field_invoke1<'f, 'g>(x: &'g Struct1<'f>) -> (int,int) {
let l = x.f.long();
let s = x.f.short();
(l,s)
}

struct Struct2<'h, 'i> {
f: &'h Trait<'i>
}

fn object_invoke2<'j, 'k>(x: &'k Trait<'j>) -> int {
x.short()
}

fn field_invoke2<'l, 'm, 'n>(x: &'n Struct2<'l,'m>) -> int {
x.f.short()
}

trait MakerTrait<'o> {
fn mk() -> Self;
}

fn make_val<'p, T:MakerTrait<'p>>() -> T {
MakerTrait::mk()
}

trait RefMakerTrait<'q> {
fn mk(Self) -> &'q Self;
}

fn make_ref<'r, T:RefMakerTrait<'r>>(t:T) -> &'r T {
RefMakerTrait::mk(t)
}

impl<'s> Trait<'s> for (int,int) {
fn long(&'s self) -> int {
let &(x,_) = self;
x
}
fn short<'b>(&'b self) -> int {
let &(_,y) = self;
y
}
}

impl<'t> MakerTrait<'t> for ~Trait<'t> {
fn mk() -> ~Trait<'t> { ~(4,5) as ~Trait }
}

enum List<'l> {
Cons(int, &'l List<'l>),
Null
}

impl<'l> List<'l> {
fn car<'m>(&'m self) -> int {
match self {
&Cons(car, _) => car,
&Null => fail!(),
}
}
fn cdr<'n>(&'n self) -> &'l List<'l> {
match self {
&Cons(_, cdr) => cdr,
&Null => fail!(),
}
}
}

impl<'t> RefMakerTrait<'t> for List<'t> {
fn mk(l:List<'t>) -> &'t List<'t> {
l.cdr()
}
}

pub fn main() {
let t = (2,3);
let o = &t as &Trait;
let s1 = Struct1 { f: o };
let s2 = Struct2 { f: o };
assert_eq!(poly_invoke(&t), (2,3));
assert_eq!(object_invoke1(&t), (2,3));
assert_eq!(field_invoke1(&s1), (2,3));
assert_eq!(object_invoke2(&t), 3);
assert_eq!(field_invoke2(&s2), 3);

let m : ~Trait = make_val();
assert_eq!(object_invoke1(m), (4,5));
assert_eq!(object_invoke2(m), 5);

// The RefMakerTrait above is pretty strange (i.e. it is strange
// to consume a value of type T and return a &T). Easiest thing
// that came to my mind: consume a cell of a linked list and
// return a reference to the list it points to.
let l0 = Null;
let l1 = Cons(1, &l0);
let l2 = Cons(2, &l1);
let rl1 = &l1;
let r = make_ref(l2);
assert_eq!(rl1.car(), r.car());
}

5 comments on commit 0cbb1ce

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@bors bors commented on 0cbb1ce Mar 29, 2014

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saw approval from nikomatsakis
at pnkfelix@0cbb1ce

@bors
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@bors bors commented on 0cbb1ce Mar 29, 2014

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merging pnkfelix/rust/fsk-iss13140 = 0cbb1ce into auto

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@bors bors commented on 0cbb1ce Mar 29, 2014

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pnkfelix/rust/fsk-iss13140 = 0cbb1ce merged ok, testing candidate = b334f7c

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@bors bors commented on 0cbb1ce Mar 29, 2014

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@bors
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@bors bors commented on 0cbb1ce Mar 29, 2014

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fast-forwarding master to auto = b334f7c

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