rust/tests/ui/consts/required-consts/collect-in-dead-closure.rs

//@revisions: noopt opt
//@ build-fail
//@[noopt] compile-flags: -Copt-level=0
//@[opt] compile-flags: -O
//! This fails without optimizations, so it should also fail with optimizations.

struct Fail<T>(T);
impl<T> Fail<T> {
    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
}

// This function is not actually called, but it is mentioned in a closure that is coerced to a
// function pointer in dead code in a function that is called. Make sure we still find this error.
#[inline(never)]
fn not_called<T>() {
    if false {
        let _ = Fail::<T>::C;
    }
}

#[inline(never)]
fn called<T>() {
    if false {
        let _closure: fn() = || not_called::<T>();
    }
}

pub fn main() {
    called::<i32>();
}