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#![warn(clippy::box_default)]
#![allow(clippy::boxed_local, clippy::default_constructed_unit_structs)]
#[derive(Default)]
struct ImplementsDefault;
struct OwnDefault;
impl OwnDefault {
fn default() -> Self {
Self
}
}
macro_rules! default {
() => {
Default::default()
};
}
macro_rules! string_new {
() => {
String::new()
};
}
macro_rules! box_new {
($e:expr) => {
Box::new($e)
};
}
fn main() {
let string1: Box<String> = Box::default();
let string2: Box<String> = Box::default();
let impl1: Box<ImplementsDefault> = Box::default();
let vec: Box<Vec<u8>> = Box::default();
let byte: Box<u8> = Box::default();
let vec2: Box<Vec<ImplementsDefault>> = Box::default();
let vec3: Box<Vec<bool>> = Box::default();
let plain_default = Box::default();
let _: Box<String> = plain_default;
let _: Box<String> = Box::new(default!());
let _: Box<String> = Box::new(string_new!());
let _: Box<String> = box_new!(Default::default());
let _: Box<String> = box_new!(String::new());
let _: Box<String> = box_new!(default!());
let _: Box<String> = box_new!(string_new!());
let own: Box<OwnDefault> = Box::new(OwnDefault::default()); // should not lint
// Do not suggest where a turbofish would be required
let impl2 = Box::new(ImplementsDefault::default());
let impl3 = Box::new(<ImplementsDefault as Default>::default());
let vec4: Box<_> = Box::new(Vec::from([false; 0]));
let more = ret_ty_fn();
call_ty_fn(Box::default());
issue_10381();
// `Box::<Option<_>>::default()` would be valid here, but not `Box::default()` or
// `Box::<Option<{closure@...}>::default()`
//
// Would have a suggestion after https://github.com/rust-lang/rust/blob/fdd030127cc68afec44a8d3f6341525dd34e50ae/compiler/rustc_middle/src/ty/diagnostics.rs#L554-L563
let mut unnameable = Box::new(Option::default());
let _ = unnameable.insert(|| {});
let _ = Box::into_raw(Box::new(String::default()));
}
fn ret_ty_fn() -> Box<bool> {
Box::new(bool::default()) // Could lint, currently doesn't
}
fn call_ty_fn(_b: Box<u8>) {
issue_9621_dyn_trait();
}
struct X<T>(T);
impl<T: Default> X<T> {
fn x(_: Box<T>) {}
fn same_generic_param() {
Self::x(Box::default());
}
}
use std::io::{Read, Result};
impl Read for ImplementsDefault {
fn read(&mut self, _: &mut [u8]) -> Result<usize> {
Ok(0)
}
}
fn issue_9621_dyn_trait() {
let _: Box<dyn Read> = Box::new(ImplementsDefault::default());
issue_10089();
}
fn issue_10089() {
let _closure = || {
#[derive(Default)]
struct WeirdPathed;
let _ = Box::new(WeirdPathed::default());
};
}
fn issue_10381() {
#[derive(Default)]
pub struct Foo {}
pub trait Bar {}
impl Bar for Foo {}
fn maybe_get_bar(i: u32) -> Option<Box<dyn Bar>> {
if i % 2 == 0 {
Some(Box::new(Foo::default()))
} else {
None
}
}
assert!(maybe_get_bar(2).is_some());
}
// Issue #11927: The quickfix for the `Box::new` suggests replacing with `Box::<Inner>::default()`,
// removing the `outer::` segment.
fn issue_11927() {
mod outer {
#[derive(Default)]
pub struct Inner {
_i: usize,
}
}
fn foo() {
let _b = Box::new(outer::Inner::default());
let _b = Box::new(std::collections::HashSet::<i32>::new());
}
}
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