rust/src/test/ui/issues/issue-40000.rs

// revisions: base nll
// ignore-compare-mode-nll
//[nll] compile-flags: -Z borrowck=mir

fn main() {
    let bar: fn(&mut u32) = |_| {};

    fn foo(x: Box<dyn Fn(&i32)>) {}
    let bar = Box::new(|x: &i32| {}) as Box<dyn Fn(_)>;
    foo(bar);
    //~^ ERROR E0308
    //[nll]~^^ ERROR mismatched types
}