0f63fa8c33
`Box::default()` had its `#[rustc_box]` attribute removed in 1.69 so is no longer a perf related lint The lint is moved to style but no longer produces suggestions containing turbofishes, as they're often longer/more annoying to type
132 lines
3.3 KiB
Rust
132 lines
3.3 KiB
Rust
#![warn(clippy::box_default)]
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#![allow(clippy::boxed_local, clippy::default_constructed_unit_structs)]
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#[derive(Default)]
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struct ImplementsDefault;
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struct OwnDefault;
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impl OwnDefault {
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fn default() -> Self {
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Self
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}
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}
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macro_rules! default {
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() => {
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Default::default()
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};
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}
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macro_rules! string_new {
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() => {
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String::new()
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};
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}
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macro_rules! box_new {
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($e:expr) => {
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Box::new($e)
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};
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}
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fn main() {
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let string1: Box<String> = Box::new(Default::default());
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let string2: Box<String> = Box::new(String::new());
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let impl1: Box<ImplementsDefault> = Box::new(Default::default());
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let vec: Box<Vec<u8>> = Box::new(Vec::new());
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let byte: Box<u8> = Box::new(u8::default());
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let vec2: Box<Vec<ImplementsDefault>> = Box::new(vec![]);
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let vec3: Box<Vec<bool>> = Box::new(Vec::from([]));
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let plain_default = Box::new(Default::default());
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let _: Box<String> = plain_default;
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let _: Box<String> = Box::new(default!());
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let _: Box<String> = Box::new(string_new!());
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let _: Box<String> = box_new!(Default::default());
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let _: Box<String> = box_new!(String::new());
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let _: Box<String> = box_new!(default!());
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let _: Box<String> = box_new!(string_new!());
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let own: Box<OwnDefault> = Box::new(OwnDefault::default()); // should not lint
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// Do not suggest where a turbofish would be required
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let impl2 = Box::new(ImplementsDefault::default());
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let impl3 = Box::new(<ImplementsDefault as Default>::default());
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let vec4: Box<_> = Box::new(Vec::from([false; 0]));
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let more = ret_ty_fn();
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call_ty_fn(Box::new(u8::default()));
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issue_10381();
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// `Box::<Option<_>>::default()` would be valid here, but not `Box::default()` or
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// `Box::<Option<{closure@...}>::default()`
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//
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// Would have a suggestion after https://github.com/rust-lang/rust/blob/fdd030127cc68afec44a8d3f6341525dd34e50ae/compiler/rustc_middle/src/ty/diagnostics.rs#L554-L563
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let mut unnameable = Box::new(Option::default());
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let _ = unnameable.insert(|| {});
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}
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fn ret_ty_fn() -> Box<bool> {
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Box::new(bool::default()) // Could lint, currently doesn't
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}
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fn call_ty_fn(_b: Box<u8>) {
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issue_9621_dyn_trait();
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}
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use std::io::{Read, Result};
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impl Read for ImplementsDefault {
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fn read(&mut self, _: &mut [u8]) -> Result<usize> {
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Ok(0)
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}
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}
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fn issue_9621_dyn_trait() {
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let _: Box<dyn Read> = Box::new(ImplementsDefault::default());
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issue_10089();
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}
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fn issue_10089() {
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let _closure = || {
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#[derive(Default)]
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struct WeirdPathed;
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let _ = Box::new(WeirdPathed::default());
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};
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}
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fn issue_10381() {
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#[derive(Default)]
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pub struct Foo {}
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pub trait Bar {}
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impl Bar for Foo {}
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fn maybe_get_bar(i: u32) -> Option<Box<dyn Bar>> {
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if i % 2 == 0 {
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Some(Box::new(Foo::default()))
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} else {
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None
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}
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}
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assert!(maybe_get_bar(2).is_some());
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}
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// Issue #11927: The quickfix for the `Box::new` suggests replacing with `Box::<Inner>::default()`,
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// removing the `outer::` segment.
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fn issue_11927() {
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mod outer {
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#[derive(Default)]
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pub struct Inner {
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_i: usize,
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}
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}
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fn foo() {
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let _b = Box::new(outer::Inner::default());
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let _b = Box::new(std::collections::HashSet::<i32>::new());
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}
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}
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