rust/tests/ui/needless_return.fixed
bors 806a9dfddd Auto merge of #13464 - y21:issue13458, r=flip1995
Don't warn on proc macro generated code in `needless_return`

Fixes #13458
Fixes #13457
Fixes #13467
Fixes #13479
Fixes #13481
Fixes #13526
Fixes #13486

The fix is unfortunately a little more convoluted than just simply adding a `is_from_proc_macro`. That check *does*  fix the issue, however it also introduces a bunch of false negatives in the tests, specifically when the returned expression is in a different syntax context, e.g. `return format!(..)`.

The proc macro check builds up a start and end pattern based on the HIR nodes and compares it to a snippet of the span, however that would currently fail for `return format!(..)` because we would have the patterns `("return", <something inside of the format macro>)`, which doesn't compare equal. So we now return an empty string pattern for when it's in a different syntax context.

"Hide whitespace" helps a bit for reviewing the proc macro detection change

changelog: none
2024-10-10 11:34:13 +02:00

391 lines
6.3 KiB
Rust

//@aux-build:proc_macros.rs
#![feature(yeet_expr)]
#![allow(unused)]
#![allow(
clippy::if_same_then_else,
clippy::single_match,
clippy::needless_bool,
clippy::equatable_if_let,
clippy::needless_else
)]
#![warn(clippy::needless_return)]
extern crate proc_macros;
use proc_macros::with_span;
use std::cell::RefCell;
macro_rules! the_answer {
() => {
42
};
}
fn test_end_of_fn() -> bool {
if true {
// no error!
return true;
}
true
}
fn test_no_semicolon() -> bool {
true
}
#[rustfmt::skip]
fn test_multiple_semicolon() -> bool {
true
}
#[rustfmt::skip]
fn test_multiple_semicolon_with_spaces() -> bool {
true
}
fn test_if_block() -> bool {
if true {
true
} else {
false
}
}
fn test_match(x: bool) -> bool {
match x {
true => false,
false => {
true
},
}
}
fn test_closure() {
let _ = || {
true
};
let _ = || true;
}
fn test_macro_call() -> i32 {
the_answer!()
}
fn test_void_fun() {
}
fn test_void_if_fun(b: bool) {
if b {
} else {
}
}
fn test_void_match(x: u32) {
match x {
0 => (),
_ => (),
}
}
fn test_nested_match(x: u32) {
match x {
0 => (),
1 => {
let _ = 42;
},
_ => (),
}
}
fn temporary_outlives_local() -> String {
let x = RefCell::<String>::default();
return x.borrow().clone();
}
fn borrows_but_not_last(value: bool) -> String {
if value {
let x = RefCell::<String>::default();
let _a = x.borrow().clone();
String::from("test")
} else {
String::new()
}
}
macro_rules! needed_return {
($e:expr) => {
if $e > 3 {
return;
}
};
}
fn test_return_in_macro() {
// This will return and the macro below won't be executed. Removing the `return` from the macro
// will change semantics.
needed_return!(10);
needed_return!(0);
}
mod issue6501 {
#[allow(clippy::unnecessary_lazy_evaluations)]
fn foo(bar: Result<(), ()>) {
bar.unwrap_or_else(|_| {})
}
fn test_closure() {
let _ = || {
};
let _ = || {};
}
struct Foo;
#[allow(clippy::unnecessary_lazy_evaluations)]
fn bar(res: Result<Foo, u8>) -> Foo {
res.unwrap_or_else(|_| Foo)
}
}
async fn async_test_end_of_fn() -> bool {
if true {
// no error!
return true;
}
true
}
async fn async_test_no_semicolon() -> bool {
true
}
async fn async_test_if_block() -> bool {
if true {
true
} else {
false
}
}
async fn async_test_match(x: bool) -> bool {
match x {
true => false,
false => {
true
},
}
}
async fn async_test_closure() {
let _ = || {
true
};
let _ = || true;
}
async fn async_test_macro_call() -> i32 {
the_answer!()
}
async fn async_test_void_fun() {
}
async fn async_test_void_if_fun(b: bool) {
if b {
} else {
}
}
async fn async_test_void_match(x: u32) {
match x {
0 => (),
_ => (),
}
}
async fn async_temporary_outlives_local() -> String {
let x = RefCell::<String>::default();
return x.borrow().clone();
}
async fn async_borrows_but_not_last(value: bool) -> String {
if value {
let x = RefCell::<String>::default();
let _a = x.borrow().clone();
String::from("test")
} else {
String::new()
}
}
async fn async_test_return_in_macro() {
needed_return!(10);
needed_return!(0);
}
fn let_else() {
let Some(1) = Some(1) else { return };
}
fn needless_return_macro() -> String {
let _ = "foo";
let _ = "bar";
format!("Hello {}", "world!")
}
fn issue_9361(n: i32) -> i32 {
#[expect(clippy::arithmetic_side_effects)]
return n + n;
}
mod issue_12998 {
fn expect_lint() -> i32 {
let x = 1;
#[expect(clippy::needless_return)]
return x;
}
fn expect_group() -> i32 {
let x = 1;
#[expect(clippy::style)]
return x;
}
fn expect_all() -> i32 {
let x = 1;
#[expect(clippy::all)]
return x;
}
fn expect_warnings() -> i32 {
let x = 1;
#[expect(warnings)]
return x;
}
}
fn issue8336(x: i32) -> bool {
if x > 0 {
println!("something");
true
} else {
false
}
}
fn issue8156(x: u8) -> u64 {
match x {
80 => {
10
},
_ => {
100
},
}
}
// Ideally the compiler should throw `unused_braces` in this case
fn issue9192() -> i32 {
{
0
}
}
fn issue9503(x: usize) -> isize {
unsafe {
if x > 12 {
*(x as *const isize)
} else {
!*(x as *const isize)
}
}
}
mod issue9416 {
pub fn with_newline() {
let _ = 42;
}
#[rustfmt::skip]
pub fn oneline() {
let _ = 42;
}
}
fn issue9947() -> Result<(), String> {
do yeet "hello";
}
// without anyhow, but triggers the same bug I believe
#[expect(clippy::useless_format)]
fn issue10051() -> Result<String, String> {
if true {
Ok(format!("ok!"))
} else {
Err(format!("err!"))
}
}
mod issue10049 {
fn single() -> u32 {
if true { 1 } else { 2 }
}
fn multiple(b1: bool, b2: bool, b3: bool) -> u32 {
(if b1 { 0 } else { 1 } | if b2 { 2 } else { 3 } | if b3 { 4 } else { 5 })
}
}
fn test_match_as_stmt() {
let x = 9;
match x {
1 => 2,
2 => return,
_ => 0,
};
}
fn allow_works() -> i32 {
#[allow(clippy::needless_return, clippy::match_single_binding)]
match () {
() => return 42,
}
}
fn conjunctive_blocks() -> String {
({ "a".to_string() } + "b" + { "c" })
}
fn issue12907() -> String {
"".split("").next().unwrap().to_string()
}
fn issue13458() {
with_span!(span return);
}
fn main() {}
fn a(x: Option<u8>) -> Option<u8> {
match x {
Some(_) => None,
None => {
#[expect(clippy::needless_return, reason = "Use early return for errors.")]
return None;
},
}
}
fn b(x: Option<u8>) -> Option<u8> {
match x {
Some(_) => None,
None => {
#[expect(clippy::needless_return)]
return None;
},
}
}