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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.
100 lines
2.0 KiB
Rust
100 lines
2.0 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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