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//! False-positive tests to ensure we don't suggest `const` for things where it would cause a
//! compilation error.
//! The .stderr output of this test should be empty. Otherwise it's a bug somewhere.
// aux-build:helper.rs
// aux-build:../../auxiliary/proc_macro_with_span.rs
#![warn(clippy::missing_const_for_fn)]
#![feature(start)]
#![feature(custom_inner_attributes)]
extern crate helper;
extern crate proc_macro_with_span;
use proc_macro_with_span::with_span;
struct Game;
// This should not be linted because it's already const
const fn already_const() -> i32 {
32
}
impl Game {
// This should not be linted because it's already const
pub const fn already_const() -> i32 {
32
}
}
// Allowing on this function, because it would lint, which we don't want in this case.
#[allow(clippy::missing_const_for_fn)]
fn random() -> u32 {
42
}
// We should not suggest to make this function `const` because `random()` is non-const
fn random_caller() -> u32 {
random()
}
static Y: u32 = 0;
// We should not suggest to make this function `const` because const functions are not allowed to
// refer to a static variable
fn get_y() -> u32 {
Y
//~^ ERROR E0013
}
// Don't lint entrypoint functions
#[start]
fn init(num: isize, something: *const *const u8) -> isize {
1
}
trait Foo {
// This should not be suggested to be made const
// (rustc doesn't allow const trait methods)
fn f() -> u32;
// This should not be suggested to be made const either
fn g() -> u32 {
33
}
}
// Don't lint in external macros (derive)
#[derive(PartialEq, Eq)]
struct Point(isize, isize);
impl std::ops::Add for Point {
type Output = Self;
// Don't lint in trait impls of derived methods
fn add(self, other: Self) -> Self {
Point(self.0 + other.0, self.1 + other.1)
}
}
mod with_drop {
pub struct A;
pub struct B;
impl Drop for A {
fn drop(&mut self) {}
}
impl A {
// This can not be const because the type implements `Drop`.
pub fn b(self) -> B {
B
}
}
impl B {
// This can not be const because `a` implements `Drop`.
pub fn a(self, a: A) -> B {
B
}
}
}
fn const_generic_params<T, const N: usize>(t: &[T; N]) -> &[T; N] {
t
}
fn const_generic_return<T, const N: usize>(t: &[T]) -> &[T; N] {
let p = t.as_ptr() as *const [T; N];
unsafe { &*p }
}
// Do not lint this because it calls a function whose constness is unstable.
fn unstably_const_fn() {
helper::unstably_const_fn()
}
mod const_fn_stabilized_after_msrv {
#![clippy::msrv = "1.46.0"]
// Do not lint this because `u8::is_ascii_digit` is stabilized as a const function in 1.47.0.
fn const_fn_stabilized_after_msrv(byte: u8) {
byte.is_ascii_digit();
}
}
with_span! {
span
fn dont_check_in_proc_macro() {}
}
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