os-rust/tests/ui/borrowck/regions-bound-missing-bound-in-impl.rs

// Check that explicit region bounds are allowed on the various
// nominal types (but not on other types) and that they are type
// checked.

struct Inv<'a> { // invariant w/r/t 'a
    x: &'a mut &'a isize
}

pub trait Foo<'a, 't> {
    fn no_bound<'b>(self, b: Inv<'b>);
    fn has_bound<'b:'a>(self, b: Inv<'b>);
    fn wrong_bound1<'b,'c,'d:'a+'b>(self, b: Inv<'b>, c: Inv<'c>, d: Inv<'d>);
    fn wrong_bound2<'b,'c,'d:'a+'b>(self, b: Inv<'b>, c: Inv<'c>, d: Inv<'d>);
    fn okay_bound<'b,'c,'d:'a+'b+'c>(self, b: Inv<'b>, c: Inv<'c>, d: Inv<'d>);
    fn another_bound<'x: 'a>(self, x: Inv<'x>, y: Inv<'t>);
}

impl<'a, 't> Foo<'a, 't> for &'a isize {
    fn no_bound<'b:'a>(self, b: Inv<'b>) {
        //~^ ERROR lifetime parameters or bounds on method `no_bound` do not match
    }

    fn has_bound<'b>(self, b: Inv<'b>) {
        //~^ ERROR lifetime parameters or bounds on method `has_bound` do not match
    }

    fn wrong_bound1<'b,'c,'d:'a+'c>(self, b: Inv<'b>, c: Inv<'c>, d: Inv<'d>) {
        //~^ ERROR method not compatible with trait
        //~| ERROR method not compatible with trait
        //
        // Note: This is a terrible error message. It is caused
        // because, in the trait, 'b is early bound, and in the impl,
        // 'c is early bound, so -- after substitution -- the
        // lifetimes themselves look isomorphic.  We fail because the
        // lifetimes that appear in the types are in the wrong
        // order. This should really be fixed by keeping more
        // information about the lifetime declarations in the trait so
        // that we can compare better to the impl, even in cross-crate
        // cases.
    }

    fn wrong_bound2(self, b: Inv, c: Inv, d: Inv) {
        //~^ ERROR lifetime parameters or bounds on method `wrong_bound2` do not match the trait
    }

    fn okay_bound<'b,'c,'e:'b+'c>(self, b: Inv<'b>, c: Inv<'c>, e: Inv<'e>) {
    }

    fn another_bound<'x: 't>(self, x: Inv<'x>, y: Inv<'t>) {
        //~^ ERROR E0276
    }
}

fn main() { }