tests/ui/mismatched_types/suggest-option-asderef-unfixable.rs

fn produces_string() -> Option<String> {
    Some("my cool string".to_owned())
}

fn takes_str_but_too_many_refs(_: &&str) -> Option<()> {
    Some(())
}

fn no_args() -> Option<()> {
    Some(())
}

extern "C" fn takes_str_but_wrong_abi(_: &str) -> Option<()> {
    Some(())
}

unsafe fn takes_str_but_unsafe(_: &str) -> Option<()> {
    Some(())
}

struct TypeWithoutDeref;

fn main() {
    let _ = produces_string().and_then(takes_str_but_too_many_refs);
    //~^ ERROR type mismatch in function arguments
    let _ = produces_string().and_then(takes_str_but_wrong_abi);
    //~^ ERROR expected a `FnOnce(String)` closure, found `for<'a> extern "C" fn(&'a str) -> Option<()> {takes_str_but_wrong_abi}`
    let _ = produces_string().and_then(takes_str_but_unsafe);
    //~^ ERROR expected a `FnOnce(String)` closure, found `for<'a> unsafe fn(&'a str) -> Option<()> {takes_str_but_unsafe}`
    let _ = produces_string().and_then(no_args);
    //~^ ERROR function is expected to take 1 argument, but it takes 0 arguments
    let _ = Some(TypeWithoutDeref).and_then(takes_str_but_too_many_refs);
    //~^ ERROR type mismatch in function arguments
}