rust-clippy/tests/ui/unit_arg.rs

// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![warn(clippy::unit_arg)]
#![allow(clippy::no_effect)]

use std::fmt::Debug;

fn foo<T: Debug>(t: T) {
    println!("{:?}", t);
}

fn foo3<T1: Debug, T2: Debug, T3: Debug>(t1: T1, t2: T2, t3: T3) {
    println!("{:?}, {:?}, {:?}", t1, t2, t3);
}

struct Bar;

impl Bar {
    fn bar<T: Debug>(&self, t: T) {
        println!("{:?}", t);
    }
}

fn bad() {
    foo({});
    foo({
        1;
    });
    foo(foo(1));
    foo({
        foo(1);
        foo(2);
    });
    foo3({}, 2, 2);
    let b = Bar;
    b.bar({
        1;
    });
}

fn ok() {
    foo(());
    foo(1);
    foo({ 1 });
    foo3("a", 3, vec![3]);
    let b = Bar;
    b.bar({ 1 });
    b.bar(());
    question_mark();
}

fn question_mark() -> Result<(), ()> {
    Ok(Ok(())?)?;
    Ok(Ok(()))??;
    Ok(())
}

fn main() {
    bad();
    ok();
}