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//@ run-pass
// Test that we are able to handle the relationships between free
// regions bound in a closure callback.
#[derive(Copy, Clone)]
struct MyCx<'short, 'long: 'short> {
short: &'short u32,
long: &'long u32,
}
impl<'short, 'long> MyCx<'short, 'long> {
fn short(self) -> &'short u32 { self.short }
fn long(self) -> &'long u32 { self.long }
fn set_short(&mut self, v: &'short u32) { self.short = v; }
}
fn with<F, R>(op: F) -> R
where
F: for<'short, 'long> FnOnce(MyCx<'short, 'long>) -> R,
{
op(MyCx {
short: &22,
long: &22,
})
}
fn main() {
with(|mut cx| {
// For this to type-check, we need to be able to deduce that
// the lifetime of `l` can be `'short`, even though it has
// input from `'long`.
let l = if true { cx.long() } else { cx.short() };
cx.set_short(l);
});
}
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