mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-30 08:30:45 +00:00
473 lines
11 KiB
Rust
473 lines
11 KiB
Rust
#![warn(clippy::redundant_closure, clippy::redundant_closure_for_method_calls)]
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#![allow(unused)]
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#![allow(
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clippy::needless_borrow,
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clippy::needless_pass_by_value,
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clippy::no_effect,
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clippy::option_map_unit_fn,
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clippy::redundant_closure_call,
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clippy::uninlined_format_args,
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clippy::useless_vec,
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clippy::unnecessary_map_on_constructor
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)]
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use std::path::{Path, PathBuf};
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macro_rules! mac {
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() => {
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foobar()
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};
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}
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macro_rules! closure_mac {
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() => {
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|n| foo(n)
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};
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}
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fn main() {
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let a = Some(1u8).map(foo);
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let c = Some(1u8).map(|a| {1+2; foo}(a));
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true.then(|| mac!()); // don't lint function in macro expansion
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Some(1).map(closure_mac!()); // don't lint closure in macro expansion
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let _: Option<Vec<u8>> = true.then(std::vec::Vec::new); // special case vec!
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let d = Some(1u8).map(|a| foo(foo2(a))); //is adjusted?
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all(&[1, 2, 3], &&2, below); //is adjusted
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unsafe {
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Some(1u8).map(|a| unsafe_fn(a)); // unsafe fn
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}
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// See #815
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let e = Some(1u8).map(|a| divergent(a));
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let e = Some(1u8).map(generic);
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let e = Some(1u8).map(generic);
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// See #515
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let a: Option<Box<dyn (::std::ops::Deref<Target = [i32]>)>> =
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Some(vec![1i32, 2]).map(|v| -> Box<dyn (::std::ops::Deref<Target = [i32]>)> { Box::new(v) });
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// issue #7224
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let _: Option<Vec<u32>> = Some(0).map(|_| vec![]);
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// issue #10684
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fn test<T>(x: impl Fn(usize, usize) -> T) -> T {
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x(1, 2)
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}
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test(|start, end| start..=end);
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}
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trait TestTrait {
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fn trait_foo(self) -> bool;
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fn trait_foo_ref(&self) -> bool;
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}
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struct TestStruct<'a> {
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some_ref: &'a i32,
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}
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impl<'a> TestStruct<'a> {
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fn foo(self) -> bool {
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false
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}
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unsafe fn foo_unsafe(self) -> bool {
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true
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}
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}
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impl<'a> TestTrait for TestStruct<'a> {
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fn trait_foo(self) -> bool {
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false
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}
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fn trait_foo_ref(&self) -> bool {
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false
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}
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}
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impl<'a> std::ops::Deref for TestStruct<'a> {
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type Target = char;
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fn deref(&self) -> &char {
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&'a'
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}
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}
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fn test_redundant_closures_containing_method_calls() {
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let i = 10;
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let e = Some(TestStruct { some_ref: &i }).map(TestStruct::foo);
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let e = Some(TestStruct { some_ref: &i }).map(TestTrait::trait_foo);
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let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo_ref());
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let e = Some(&mut vec![1, 2, 3]).map(std::vec::Vec::clear);
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unsafe {
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let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo_unsafe());
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}
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let e = Some("str").map(std::string::ToString::to_string);
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let e = Some('a').map(char::to_uppercase);
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let e: std::vec::Vec<usize> = vec!['a', 'b', 'c'].iter().map(|c| c.len_utf8()).collect();
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let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(char::to_ascii_uppercase).collect();
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let e = Some(PathBuf::new()).as_ref().and_then(|s| s.to_str());
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let c = Some(TestStruct { some_ref: &i })
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.as_ref()
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.map(|c| c.to_ascii_uppercase());
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fn test_different_borrow_levels<T>(t: &[&T])
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where
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T: TestTrait,
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{
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t.iter().filter(|x| x.trait_foo_ref());
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t.iter().map(|x| x.trait_foo_ref());
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}
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}
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struct Thunk<T>(Box<dyn FnMut() -> T>);
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impl<T> Thunk<T> {
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fn new<F: 'static + FnOnce() -> T>(f: F) -> Thunk<T> {
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let mut option = Some(f);
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// This should not trigger redundant_closure (#1439)
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Thunk(Box::new(move || option.take().unwrap()()))
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}
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fn unwrap(self) -> T {
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let Thunk(mut f) = self;
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f()
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}
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}
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fn foobar() {
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let thunk = Thunk::new(|| println!("Hello, world!"));
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thunk.unwrap()
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}
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fn foo(_: u8) {}
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fn foo2(_: u8) -> u8 {
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1u8
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}
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fn all<X, F>(x: &[X], y: &X, f: F) -> bool
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where
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F: Fn(&X, &X) -> bool,
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{
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x.iter().all(|e| f(e, y))
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}
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fn below(x: &u8, y: &u8) -> bool {
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x < y
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}
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unsafe fn unsafe_fn(_: u8) {}
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fn divergent(_: u8) -> ! {
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unimplemented!()
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}
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fn generic<T>(_: T) -> u8 {
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0
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}
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fn passes_fn_mut(mut x: Box<dyn FnMut()>) {
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requires_fn_once(x);
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}
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fn requires_fn_once<T: FnOnce()>(_: T) {}
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fn test_redundant_closure_with_function_pointer() {
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type FnPtrType = fn(u8);
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let foo_ptr: FnPtrType = foo;
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let a = Some(1u8).map(foo_ptr);
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}
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fn test_redundant_closure_with_another_closure() {
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let closure = |a| println!("{}", a);
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let a = Some(1u8).map(closure);
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}
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fn make_lazy(f: impl Fn() -> fn(u8) -> u8) -> impl Fn(u8) -> u8 {
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// Currently f is called when result of make_lazy is called.
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// If the closure is removed, f will be called when make_lazy itself is
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// called. This changes semantics, so the closure must stay.
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Box::new(move |x| f()(x))
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}
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fn call<F: FnOnce(&mut String) -> String>(f: F) -> String {
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f(&mut "Hello".to_owned())
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}
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fn test_difference_in_mutability() {
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call(|s| s.clone());
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}
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struct Bar;
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impl std::ops::Deref for Bar {
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type Target = str;
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fn deref(&self) -> &str {
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"hi"
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}
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}
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fn test_deref_with_trait_method() {
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let _ = [Bar].iter().map(|s| s.to_string()).collect::<Vec<_>>();
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}
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fn mutable_closure_used_again(x: Vec<i32>, y: Vec<i32>, z: Vec<i32>) {
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let mut res = Vec::new();
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let mut add_to_res = |n| res.push(n);
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x.into_iter().for_each(&mut add_to_res);
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y.into_iter().for_each(&mut add_to_res);
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z.into_iter().for_each(add_to_res);
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}
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fn mutable_closure_in_loop() {
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let mut value = 0;
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let mut closure = |n| value += n;
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for _ in 0..5 {
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Some(1).map(&mut closure);
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let mut value = 0;
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let mut in_loop = |n| value += n;
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Some(1).map(in_loop);
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}
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}
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fn late_bound_lifetimes() {
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fn take_asref_path<P: AsRef<Path>>(path: P) {}
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fn map_str<F>(thunk: F)
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where
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F: FnOnce(&str),
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{
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}
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fn map_str_to_path<F>(thunk: F)
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where
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F: FnOnce(&str) -> &Path,
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{
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}
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map_str(|s| take_asref_path(s));
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map_str_to_path(|s| s.as_ref());
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}
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mod type_param_bound {
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trait Trait {
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fn fun();
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}
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fn take<T: 'static>(_: T) {}
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fn test<X: Trait>() {
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// don't lint, but it's questionable that rust requires a cast
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take(|| X::fun());
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take(X::fun as fn());
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}
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}
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// #8073 Don't replace closure with `Arc<F>` or `Rc<F>`
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fn arc_fp() {
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let rc = std::rc::Rc::new(|| 7);
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let arc = std::sync::Arc::new(|n| n + 1);
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let ref_arc = &std::sync::Arc::new(|_| 5);
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true.then(|| rc());
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(0..5).map(|n| arc(n));
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Some(4).map(|n| ref_arc(n));
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}
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// #8460 Don't replace closures with params bounded as `ref`
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mod bind_by_ref {
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struct A;
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struct B;
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impl From<&A> for B {
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fn from(A: &A) -> Self {
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B
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}
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}
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fn test() {
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// should not lint
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Some(A).map(|a| B::from(&a));
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// should not lint
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Some(A).map(|ref a| B::from(a));
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}
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}
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// #7812 False positive on coerced closure
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fn coerced_closure() {
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fn function_returning_unit<F: FnMut(i32)>(f: F) {}
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function_returning_unit(|x| std::process::exit(x));
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fn arr() -> &'static [u8; 0] {
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&[]
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}
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fn slice_fn(_: impl FnOnce() -> &'static [u8]) {}
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slice_fn(|| arr());
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}
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// https://github.com/rust-lang/rust-clippy/issues/7861
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fn box_dyn() {
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fn f(_: impl Fn(usize) -> Box<dyn std::any::Any>) {}
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f(|x| Box::new(x));
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}
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// https://github.com/rust-lang/rust-clippy/issues/5939
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fn not_general_enough() {
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fn f(_: impl FnMut(&Path) -> std::io::Result<()>) {}
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f(|path| std::fs::remove_file(path));
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}
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// https://github.com/rust-lang/rust-clippy/issues/9369
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pub fn mutable_impl_fn_mut(mut f: impl FnMut(), mut f_used_once: impl FnMut()) -> impl FnMut() {
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fn takes_fn_mut(_: impl FnMut()) {}
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takes_fn_mut(&mut f);
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fn takes_fn_once(_: impl FnOnce()) {}
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takes_fn_once(&mut f);
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f();
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move || takes_fn_mut(&mut f_used_once)
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}
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impl dyn TestTrait + '_ {
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fn method_on_dyn(&self) -> bool {
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false
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}
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}
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// https://github.com/rust-lang/rust-clippy/issues/7746
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fn angle_brackets_and_args() {
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let array_opt: Option<&[u8; 3]> = Some(&[4, 8, 7]);
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array_opt.map(<[u8; 3]>::as_slice);
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let slice_opt: Option<&[u8]> = Some(b"slice");
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slice_opt.map(<[u8]>::len);
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let ptr_opt: Option<*const usize> = Some(&487);
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ptr_opt.map(<*const usize>::is_null);
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let test_struct = TestStruct { some_ref: &487 };
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let dyn_opt: Option<&dyn TestTrait> = Some(&test_struct);
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dyn_opt.map(<dyn TestTrait>::method_on_dyn);
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}
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// https://github.com/rust-lang/rust-clippy/issues/12199
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fn track_caller_fp() {
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struct S;
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impl S {
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#[track_caller]
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fn add_location(self) {}
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}
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#[track_caller]
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fn add_location() {}
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fn foo(_: fn()) {}
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fn foo2(_: fn(S)) {}
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foo(|| add_location());
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foo2(|s| s.add_location());
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}
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fn _late_bound_to_early_bound_regions() {
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struct Foo<'a>(&'a u32);
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impl<'a> Foo<'a> {
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fn f(x: &'a u32) -> Self {
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Foo(x)
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}
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}
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fn f(f: impl for<'a> Fn(&'a u32) -> Foo<'a>) -> Foo<'static> {
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f(&0)
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}
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let _ = f(|x| Foo::f(x));
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struct Bar;
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impl<'a> From<&'a u32> for Bar {
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fn from(x: &'a u32) -> Bar {
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Bar
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}
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}
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fn f2(f: impl for<'a> Fn(&'a u32) -> Bar) -> Bar {
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f(&0)
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}
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let _ = f2(|x| <Bar>::from(x));
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struct Baz<'a>(&'a u32);
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fn f3(f: impl Fn(&u32) -> Baz<'_>) -> Baz<'static> {
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f(&0)
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}
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let _ = f3(|x| Baz(x));
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}
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fn _mixed_late_bound_and_early_bound_regions() {
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fn f<T>(t: T, f: impl Fn(T, &u32) -> u32) -> u32 {
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f(t, &0)
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}
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fn f2<'a, T: 'a>(_: &'a T, y: &u32) -> u32 {
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*y
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}
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let _ = f(&0, f2);
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}
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fn _closure_with_types() {
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fn f<T>(x: T) -> T {
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x
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}
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fn f2<T: Default>(f: impl Fn(T) -> T) -> T {
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f(T::default())
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}
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let _ = f2(|x: u32| f(x));
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let _ = f2(|x| -> u32 { f(x) });
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}
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/// https://github.com/rust-lang/rust-clippy/issues/10854
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/// This is to verify that redundant_closure_for_method_calls resolves suggested paths to relative.
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mod issue_10854 {
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pub mod test_mod {
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pub struct Test;
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impl Test {
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pub fn method(self) -> i32 {
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0
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}
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}
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pub fn calls_test(test: Option<Test>) -> Option<i32> {
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test.map(Test::method)
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}
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pub fn calls_outer(test: Option<super::Outer>) -> Option<i32> {
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test.map(super::Outer::method)
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}
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}
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pub struct Outer;
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impl Outer {
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pub fn method(self) -> i32 {
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0
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}
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}
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pub fn calls_into_mod(test: Option<test_mod::Test>) -> Option<i32> {
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test.map(test_mod::Test::method)
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}
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mod a {
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pub mod b {
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pub mod c {
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pub fn extreme_nesting(test: Option<super::super::super::d::Test>) -> Option<i32> {
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test.map(crate::issue_10854::d::Test::method)
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}
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}
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}
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}
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mod d {
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pub struct Test;
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impl Test {
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pub fn method(self) -> i32 {
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0
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}
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}
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}
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}
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