rust/src/test/run-pass/regions-no-variance-from-fn-generics.rs

// 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.

// Issue #12856: a lifetime formal binding introduced by a generic fn
// should not upset the variance inference for actual occurrences of
// that lifetime in type expressions.

pub trait HasLife<'a> {
    fn dummy(&'a self) { } // just to induce a variance on 'a
}

trait UseLife01 {
    fn refs<'a, H: HasLife<'a>>(&'a self) -> H;
}

trait UseLife02 {
    fn refs<'a, T, H: HasType<&'a T>>(&'a self) -> H;
}


pub trait HasType<T>
{
    fn dummy(&self, t: T) -> T { panic!() }
}


trait UseLife03<T> {
    fn refs<'a, H: HasType<&'a T>>(&'a self) -> H;
}


// (The functions below were not actually a problem observed during
// fixing of #12856; they just seem like natural tests to put in to
// cover a couple more points in the testing space)

pub fn top_refs_1<'a, H: HasLife<'a>>(_s: &'a ()) -> H {
    unimplemented!()
}

pub fn top_refs_2<'a, T, H: HasType<&'a T>>(_s: &'a ()) -> H {
    unimplemented!()
}

pub fn main() {}