rust/tests/ui/float_cmp.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::float_cmp)]
#![allow(unused, clippy::no_effect, clippy::unnecessary_operation, clippy::cast_lossless)]

use std::ops::Add;

const ZERO: f32 = 0.0;
const ONE: f32 = ZERO + 1.0;

fn twice<T>(x: T) -> T
where
    T: Add<T, Output = T>,
    T: Copy,
{
    x + x
}

fn eq_fl(x: f32, y: f32) -> bool {
    if x.is_nan() {
        y.is_nan()
    } else {
        x == y
    } // no error, inside "eq" fn
}

fn fl_eq(x: f32, y: f32) -> bool {
    if x.is_nan() {
        y.is_nan()
    } else {
        x == y
    } // no error, inside "eq" fn
}

struct X {
    val: f32,
}

impl PartialEq for X {
    fn eq(&self, o: &X) -> bool {
        if self.val.is_nan() {
            o.val.is_nan()
        } else {
            self.val == o.val // no error, inside "eq" fn
        }
    }
}

fn main() {
    ZERO == 0f32; //no error, comparison with zero is ok
    1.0f32 != ::std::f32::INFINITY; // also comparison with infinity
    1.0f32 != ::std::f32::NEG_INFINITY; // and negative infinity
    ZERO == 0.0; //no error, comparison with zero is ok
    ZERO + ZERO != 1.0; //no error, comparison with zero is ok

    ONE == 1f32;
    ONE == 1.0 + 0.0;
    ONE + ONE == ZERO + ONE + ONE;
    ONE != 2.0;
    ONE != 0.0; // no error, comparison with zero is ok
    twice(ONE) != ONE;
    ONE as f64 != 2.0;
    ONE as f64 != 0.0; // no error, comparison with zero is ok

    let x: f64 = 1.0;

    x == 1.0;
    x != 0f64; // no error, comparison with zero is ok

    twice(x) != twice(ONE as f64);

    x < 0.0; // no errors, lower or greater comparisons need no fuzzyness
    x > 0.0;
    x <= 0.0;
    x >= 0.0;

    let xs: [f32; 1] = [0.0];
    let a: *const f32 = xs.as_ptr();
    let b: *const f32 = xs.as_ptr();

    assert_eq!(a, b); // no errors
}