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#![warn(clippy::box_default)]
#![allow(clippy::default_constructed_unit_structs)]
#[derive(Default)]
struct ImplementsDefault;
struct OwnDefault;
impl OwnDefault {
fn default() -> Self {
Self
}
}
macro_rules! outer {
($e: expr) => {
$e
};
}
fn main() {
let _string: Box<String> = Box::new(Default::default());
let _byte = Box::new(u8::default());
let _vec = Box::new(Vec::<u8>::new());
let _impl = Box::new(ImplementsDefault::default());
let _impl2 = Box::new(<ImplementsDefault as Default>::default());
let _impl3: Box<ImplementsDefault> = Box::new(Default::default());
let _own = Box::new(OwnDefault::default()); // should not lint
let _in_macro = outer!(Box::new(String::new()));
let _string_default = outer!(Box::new(String::from("")));
let _vec2: Box<Vec<ImplementsDefault>> = Box::new(vec![]);
let _vec3: Box<Vec<bool>> = Box::new(Vec::from([]));
let _vec4: Box<_> = Box::new(Vec::from([false; 0]));
let _more = ret_ty_fn();
call_ty_fn(Box::new(u8::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(|| {});
}
fn ret_ty_fn() -> Box<bool> {
Box::new(bool::default())
}
#[allow(clippy::boxed_local)]
fn call_ty_fn(_b: Box<u8>) {
issue_9621_dyn_trait();
}
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());
}
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