rust-clippy/tests/ui/slow_vector_initialization.rs

100 lines
2.9 KiB
Rust

use std::iter::repeat;
//@no-rustfix
fn main() {
resize_vector();
extend_vector();
mixed_extend_resize_vector();
from_empty_vec();
}
fn extend_vector() {
// Extend with constant expression
let len = 300;
let mut vec1 = Vec::with_capacity(len);
vec1.extend(repeat(0).take(len));
//~^ ERROR: slow zero-filling initialization
//~| NOTE: `-D clippy::slow-vector-initialization` implied by `-D warnings`
// Extend with len expression
let mut vec2 = Vec::with_capacity(len - 10);
vec2.extend(repeat(0).take(len - 10));
//~^ ERROR: slow zero-filling initialization
// Extend with mismatching expression should not be warned
let mut vec3 = Vec::with_capacity(24322);
vec3.extend(repeat(0).take(2));
let mut vec4 = Vec::with_capacity(len);
vec4.extend(repeat(0).take(vec4.capacity()));
//~^ ERROR: slow zero-filling initialization
}
fn mixed_extend_resize_vector() {
// Mismatching len
let mut mismatching_len = Vec::with_capacity(30);
mismatching_len.extend(repeat(0).take(40));
// Slow initialization
let mut resized_vec = Vec::with_capacity(30);
resized_vec.resize(30, 0);
//~^ ERROR: slow zero-filling initialization
let mut extend_vec = Vec::with_capacity(30);
extend_vec.extend(repeat(0).take(30));
//~^ ERROR: slow zero-filling initialization
}
fn resize_vector() {
// Resize with constant expression
let len = 300;
let mut vec1 = Vec::with_capacity(len);
vec1.resize(len, 0);
//~^ ERROR: slow zero-filling initialization
// Resize mismatch len
let mut vec2 = Vec::with_capacity(200);
vec2.resize(10, 0);
// Resize with len expression
let mut vec3 = Vec::with_capacity(len - 10);
vec3.resize(len - 10, 0);
//~^ ERROR: slow zero-filling initialization
let mut vec4 = Vec::with_capacity(len);
vec4.resize(vec4.capacity(), 0);
//~^ ERROR: slow zero-filling initialization
// Reinitialization should be warned
vec1 = Vec::with_capacity(10);
vec1.resize(10, 0);
//~^ ERROR: slow zero-filling initialization
}
fn from_empty_vec() {
// Resize with constant expression
let len = 300;
let mut vec1 = Vec::new();
vec1.resize(len, 0);
//~^ ERROR: slow zero-filling initialization
// Resize with len expression
let mut vec3 = Vec::new();
vec3.resize(len - 10, 0);
//~^ ERROR: slow zero-filling initialization
// Reinitialization should be warned
vec1 = Vec::new();
vec1.resize(10, 0);
//~^ ERROR: slow zero-filling initialization
}
fn do_stuff(vec: &mut [u8]) {}
//~^ ERROR: this argument is a mutable reference, but not used mutably
//~| NOTE: `-D clippy::needless-pass-by-ref-mut` implied by `-D warnings`
fn extend_vector_with_manipulations_between() {
let len = 300;
let mut vec1: Vec<u8> = Vec::with_capacity(len);
do_stuff(&mut vec1);
vec1.extend(repeat(0).take(len));
}