rust/tests/ui/eta.rs

348 lines
8.3 KiB
Rust

//@run-rustfix
#![warn(clippy::redundant_closure, clippy::redundant_closure_for_method_calls)]
#![allow(unused)]
#![allow(
clippy::needless_borrow,
clippy::needless_pass_by_value,
clippy::no_effect,
clippy::option_map_unit_fn,
clippy::redundant_closure_call,
clippy::uninlined_format_args,
clippy::useless_vec
)]
use std::path::{Path, PathBuf};
macro_rules! mac {
() => {
foobar()
};
}
macro_rules! closure_mac {
() => {
|n| foo(n)
};
}
fn main() {
let a = Some(1u8).map(|a| foo(a));
let c = Some(1u8).map(|a| {1+2; foo}(a));
true.then(|| mac!()); // don't lint function in macro expansion
Some(1).map(closure_mac!()); // don't lint closure in macro expansion
let _: Option<Vec<u8>> = true.then(|| vec![]); // special case vec!
let d = Some(1u8).map(|a| foo((|b| foo2(b))(a))); //is adjusted?
all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted
unsafe {
Some(1u8).map(|a| unsafe_fn(a)); // unsafe fn
}
// See #815
let e = Some(1u8).map(|a| divergent(a));
let e = Some(1u8).map(|a| generic(a));
let e = Some(1u8).map(generic);
// See #515
let a: Option<Box<dyn (::std::ops::Deref<Target = [i32]>)>> =
Some(vec![1i32, 2]).map(|v| -> Box<dyn (::std::ops::Deref<Target = [i32]>)> { Box::new(v) });
// issue #7224
let _: Option<Vec<u32>> = Some(0).map(|_| vec![]);
// issue #10684
fn test<T>(x: impl Fn(usize, usize) -> T) -> T {
x(1, 2)
}
test(|start, end| start..=end);
}
trait TestTrait {
fn trait_foo(self) -> bool;
fn trait_foo_ref(&self) -> bool;
}
struct TestStruct<'a> {
some_ref: &'a i32,
}
impl<'a> TestStruct<'a> {
fn foo(self) -> bool {
false
}
unsafe fn foo_unsafe(self) -> bool {
true
}
}
impl<'a> TestTrait for TestStruct<'a> {
fn trait_foo(self) -> bool {
false
}
fn trait_foo_ref(&self) -> bool {
false
}
}
impl<'a> std::ops::Deref for TestStruct<'a> {
type Target = char;
fn deref(&self) -> &char {
&'a'
}
}
fn test_redundant_closures_containing_method_calls() {
let i = 10;
let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo());
let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo());
let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo_ref());
let e = Some(&mut vec![1, 2, 3]).map(|v| v.clear());
unsafe {
let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo_unsafe());
}
let e = Some("str").map(|s| s.to_string());
let e = Some('a').map(|s| s.to_uppercase());
let e: std::vec::Vec<usize> = vec!['a', 'b', 'c'].iter().map(|c| c.len_utf8()).collect();
let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_ascii_uppercase()).collect();
let e = Some(PathBuf::new()).as_ref().and_then(|s| s.to_str());
let c = Some(TestStruct { some_ref: &i })
.as_ref()
.map(|c| c.to_ascii_uppercase());
fn test_different_borrow_levels<T>(t: &[&T])
where
T: TestTrait,
{
t.iter().filter(|x| x.trait_foo_ref());
t.iter().map(|x| x.trait_foo_ref());
}
}
struct Thunk<T>(Box<dyn FnMut() -> T>);
impl<T> Thunk<T> {
fn new<F: 'static + FnOnce() -> T>(f: F) -> Thunk<T> {
let mut option = Some(f);
// This should not trigger redundant_closure (#1439)
Thunk(Box::new(move || option.take().unwrap()()))
}
fn unwrap(self) -> T {
let Thunk(mut f) = self;
f()
}
}
fn foobar() {
let thunk = Thunk::new(|| println!("Hello, world!"));
thunk.unwrap()
}
fn foo(_: u8) {}
fn foo2(_: u8) -> u8 {
1u8
}
fn all<X, F>(x: &[X], y: &X, f: F) -> bool
where
F: Fn(&X, &X) -> bool,
{
x.iter().all(|e| f(e, y))
}
fn below(x: &u8, y: &u8) -> bool {
x < y
}
unsafe fn unsafe_fn(_: u8) {}
fn divergent(_: u8) -> ! {
unimplemented!()
}
fn generic<T>(_: T) -> u8 {
0
}
fn passes_fn_mut(mut x: Box<dyn FnMut()>) {
requires_fn_once(|| x());
}
fn requires_fn_once<T: FnOnce()>(_: T) {}
fn test_redundant_closure_with_function_pointer() {
type FnPtrType = fn(u8);
let foo_ptr: FnPtrType = foo;
let a = Some(1u8).map(|a| foo_ptr(a));
}
fn test_redundant_closure_with_another_closure() {
let closure = |a| println!("{}", a);
let a = Some(1u8).map(|a| closure(a));
}
fn make_lazy(f: impl Fn() -> fn(u8) -> u8) -> impl Fn(u8) -> u8 {
// Currently f is called when result of make_lazy is called.
// If the closure is removed, f will be called when make_lazy itself is
// called. This changes semantics, so the closure must stay.
Box::new(move |x| f()(x))
}
fn call<F: FnOnce(&mut String) -> String>(f: F) -> String {
f(&mut "Hello".to_owned())
}
fn test_difference_in_mutability() {
call(|s| s.clone());
}
struct Bar;
impl std::ops::Deref for Bar {
type Target = str;
fn deref(&self) -> &str {
"hi"
}
}
fn test_deref_with_trait_method() {
let _ = [Bar].iter().map(|s| s.to_string()).collect::<Vec<_>>();
}
fn mutable_closure_used_again(x: Vec<i32>, y: Vec<i32>, z: Vec<i32>) {
let mut res = Vec::new();
let mut add_to_res = |n| res.push(n);
x.into_iter().for_each(|x| add_to_res(x));
y.into_iter().for_each(|x| add_to_res(x));
z.into_iter().for_each(|x| add_to_res(x));
}
fn mutable_closure_in_loop() {
let mut value = 0;
let mut closure = |n| value += n;
for _ in 0..5 {
Some(1).map(|n| closure(n));
let mut value = 0;
let mut in_loop = |n| value += n;
Some(1).map(|n| in_loop(n));
}
}
fn late_bound_lifetimes() {
fn take_asref_path<P: AsRef<Path>>(path: P) {}
fn map_str<F>(thunk: F)
where
F: FnOnce(&str),
{
}
fn map_str_to_path<F>(thunk: F)
where
F: FnOnce(&str) -> &Path,
{
}
map_str(|s| take_asref_path(s));
map_str_to_path(|s| s.as_ref());
}
mod type_param_bound {
trait Trait {
fn fun();
}
fn take<T: 'static>(_: T) {}
fn test<X: Trait>() {
// don't lint, but it's questionable that rust requires a cast
take(|| X::fun());
take(X::fun as fn());
}
}
// #8073 Don't replace closure with `Arc<F>` or `Rc<F>`
fn arc_fp() {
let rc = std::rc::Rc::new(|| 7);
let arc = std::sync::Arc::new(|n| n + 1);
let ref_arc = &std::sync::Arc::new(|_| 5);
true.then(|| rc());
(0..5).map(|n| arc(n));
Some(4).map(|n| ref_arc(n));
}
// #8460 Don't replace closures with params bounded as `ref`
mod bind_by_ref {
struct A;
struct B;
impl From<&A> for B {
fn from(A: &A) -> Self {
B
}
}
fn test() {
// should not lint
Some(A).map(|a| B::from(&a));
// should not lint
Some(A).map(|ref a| B::from(a));
}
}
// #7812 False positive on coerced closure
fn coerced_closure() {
fn function_returning_unit<F: FnMut(i32)>(f: F) {}
function_returning_unit(|x| std::process::exit(x));
fn arr() -> &'static [u8; 0] {
&[]
}
fn slice_fn(_: impl FnOnce() -> &'static [u8]) {}
slice_fn(|| arr());
}
// https://github.com/rust-lang/rust-clippy/issues/7861
fn box_dyn() {
fn f(_: impl Fn(usize) -> Box<dyn std::any::Any>) {}
f(|x| Box::new(x));
}
// https://github.com/rust-lang/rust-clippy/issues/5939
fn not_general_enough() {
fn f(_: impl FnMut(&Path) -> std::io::Result<()>) {}
f(|path| std::fs::remove_file(path));
}
// https://github.com/rust-lang/rust-clippy/issues/9369
pub fn mutable_impl_fn_mut(mut f: impl FnMut(), mut f_used_once: impl FnMut()) -> impl FnMut() {
fn takes_fn_mut(_: impl FnMut()) {}
takes_fn_mut(|| f());
fn takes_fn_once(_: impl FnOnce()) {}
takes_fn_once(|| f());
f();
move || takes_fn_mut(|| f_used_once())
}
impl dyn TestTrait + '_ {
fn method_on_dyn(&self) -> bool {
false
}
}
// https://github.com/rust-lang/rust-clippy/issues/7746
fn angle_brackets_and_substs() {
let array_opt: Option<&[u8; 3]> = Some(&[4, 8, 7]);
array_opt.map(|a| a.as_slice());
let slice_opt: Option<&[u8]> = Some(b"slice");
slice_opt.map(|s| s.len());
let ptr_opt: Option<*const usize> = Some(&487);
ptr_opt.map(|p| p.is_null());
let test_struct = TestStruct { some_ref: &487 };
let dyn_opt: Option<&dyn TestTrait> = Some(&test_struct);
dyn_opt.map(|d| d.method_on_dyn());
}