mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-12-01 00:49:30 +00:00
0ef5dee3b8
Update the "borrow box" lint to avoid recommending the following
conversion:
```
// Old
pub fn f(&mut Box<T>) {...}
// New
pub fn f(&mut T) {...}
```
Given a mutable reference to a box, functions may want to change
"which" object the Box is pointing at.
This change avoids recommending removing the "Box" parameter
for mutable references.
99 lines
2 KiB
Rust
99 lines
2 KiB
Rust
#![deny(clippy::borrowed_box)]
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#![allow(clippy::blacklisted_name)]
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#![allow(unused_variables)]
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#![allow(dead_code)]
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pub fn test1(foo: &mut Box<bool>) {
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// Although this function could be changed to "&mut bool",
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// avoiding the Box, mutable references to boxes are not
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// flagged by this lint.
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//
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// This omission is intentional: By passing a mutable Box,
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// the memory location of the pointed-to object could be
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// modified. By passing a mutable reference, the contents
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// could change, but not the location.
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println!("{:?}", foo)
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}
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pub fn test2() {
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let foo: &Box<bool>;
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}
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struct Test3<'a> {
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foo: &'a Box<bool>,
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}
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trait Test4 {
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fn test4(a: &Box<bool>);
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}
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impl<'a> Test4 for Test3<'a> {
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fn test4(a: &Box<bool>) {
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unimplemented!();
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}
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}
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use std::any::Any;
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pub fn test5(foo: &mut Box<dyn Any>) {
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println!("{:?}", foo)
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}
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pub fn test6() {
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let foo: &Box<dyn Any>;
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}
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struct Test7<'a> {
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foo: &'a Box<dyn Any>,
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}
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trait Test8 {
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fn test8(a: &Box<dyn Any>);
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}
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impl<'a> Test8 for Test7<'a> {
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fn test8(a: &Box<dyn Any>) {
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unimplemented!();
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}
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}
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pub fn test9(foo: &mut Box<dyn Any + Send + Sync>) {
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let _ = foo;
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}
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pub fn test10() {
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let foo: &Box<dyn Any + Send + 'static>;
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}
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struct Test11<'a> {
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foo: &'a Box<dyn Any + Send>,
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}
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trait Test12 {
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fn test4(a: &Box<dyn Any + 'static>);
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}
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impl<'a> Test12 for Test11<'a> {
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fn test4(a: &Box<dyn Any + 'static>) {
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unimplemented!();
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}
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}
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pub fn test13(boxed_slice: &mut Box<[i32]>) {
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// Unconditionally replaces the box pointer.
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//
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// This cannot be accomplished if "&mut [i32]" is passed,
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// and provides a test case where passing a reference to
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// a Box is valid.
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let mut data = vec![12];
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*boxed_slice = data.into_boxed_slice();
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}
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fn main() {
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test1(&mut Box::new(false));
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test2();
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test5(&mut (Box::new(false) as Box<dyn Any>));
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test6();
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test9(&mut (Box::new(false) as Box<dyn Any + Send + Sync>));
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test10();
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}
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