rust/tests/ui/manual_slice_size_calculation.rs

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//@run-rustfix
//@aux-build:proc_macros.rs:proc-macro
#![allow(unused)]
#![warn(clippy::manual_slice_size_calculation)]
extern crate proc_macros;
use core::mem::{align_of, size_of};
use proc_macros::external;
fn main() {
let v_i32 = Vec::<i32>::new();
let s_i32 = v_i32.as_slice();
// True positives:
let _ = s_i32.len() * size_of::<i32>(); // WARNING
let _ = size_of::<i32>() * s_i32.len(); // WARNING
let _ = size_of::<i32>() * s_i32.len() * 5; // WARNING
let len = s_i32.len();
let size = size_of::<i32>();
let _ = len * size_of::<i32>(); // WARNING
let _ = s_i32.len() * size; // WARNING
let _ = len * size; // WARNING
let _ = external!(&[1u64][..]).len() * size_of::<u64>();
// True negatives:
let _ = size_of::<i32>() + s_i32.len(); // Ok, not a multiplication
let _ = size_of::<i32>() * s_i32.partition_point(|_| true); // Ok, not len()
let _ = size_of::<i32>() * v_i32.len(); // Ok, not a slice
let _ = align_of::<i32>() * s_i32.len(); // Ok, not size_of()
let _ = size_of::<u32>() * s_i32.len(); // Ok, different types
let _ = external!($s_i32.len() * size_of::<i32>());
let _ = external!($s_i32.len()) * size_of::<i32>();
// False negatives:
let _ = 5 * size_of::<i32>() * s_i32.len(); // Ok (MISSED OPPORTUNITY)
let _ = size_of::<i32>() * 5 * s_i32.len(); // Ok (MISSED OPPORTUNITY)
}
const fn _const(s_i32: &[i32]) {
// True negative:
let _ = s_i32.len() * size_of::<i32>(); // Ok, can't use size_of_val in const
}