rust-clippy/tests/ui/modulo_one.rs

#![warn(clippy::modulo_one)]
#![allow(clippy::no_effect, clippy::unnecessary_operation, clippy::identity_op)]

static STATIC_ONE: usize = 2 - 1;
static STATIC_NEG_ONE: i64 = 1 - 2;

fn main() {
    10 % 1;
    //~^ ERROR: any number modulo 1 will be 0
    //~| NOTE: `-D clippy::modulo-one` implied by `-D warnings`
    10 % -1;
    //~^ ERROR: any number modulo -1 will panic/overflow or result in 0
    10 % 2;
    // also caught by rustc
    i32::MIN % (-1);
    //~^ ERROR: this operation will panic at runtime
    //~| NOTE: `#[deny(unconditional_panic)]` on by default
    //~| ERROR: any number modulo -1 will panic/overflow or result in 0

    const ONE: u32 = 1 * 1;
    const NEG_ONE: i64 = 1 - 2;
    const INT_MIN: i64 = i64::MIN;

    2 % ONE;
    //~^ ERROR: any number modulo 1 will be 0
    // NOT caught by lint
    5 % STATIC_ONE;
    2 % NEG_ONE;
    //~^ ERROR: any number modulo -1 will panic/overflow or result in 0
    // NOT caught by lint
    5 % STATIC_NEG_ONE;
    // also caught by rustc
    INT_MIN % NEG_ONE;
    //~^ ERROR: this operation will panic at runtime
    //~| ERROR: any number modulo -1 will panic/overflow or result in 0
    // Not caught by lint, we don't look into static items, even if entirely immutable.
    INT_MIN % STATIC_NEG_ONE;
}