#![allow(warnings)] struct Foo<'a, 'b, T: 'a + 'b> { x: &'a T, y: &'b T } fn gimme(_: impl for<'a, 'b, 'c> FnOnce(&'a Foo<'a, 'b, u32>, &'a Foo<'a, 'c, u32>) -> &'a Foo<'a, 'b, u32>) { } fn main() { gimme(|x, y| y) //~^ ERROR lifetime may not live long enough }