diff options
| -rw-r--r-- | clippy_lints/src/types.rs | 14 | ||||
| -rw-r--r-- | tests/ui/borrow_box.rs | 18 | ||||
| -rw-r--r-- | tests/ui/borrow_box.stderr | 18 |
3 files changed, 31 insertions, 19 deletions
diff --git a/clippy_lints/src/types.rs b/clippy_lints/src/types.rs index 31d8daa2d97..153a2b7249c 100644 --- a/clippy_lints/src/types.rs +++ b/clippy_lints/src/types.rs @@ -531,11 +531,12 @@ impl Types { } else { format!("{} ", lt.name.ident().as_str()) }; - let mutopt = if mut_ty.mutbl == Mutability::Mut { - "mut " - } else { - "" - }; + + if mut_ty.mutbl == Mutability::Mut { + // Ignore `&mut Box<T>` types; see issue #2907 for + // details. + return; + } let mut applicability = Applicability::MachineApplicable; span_lint_and_sugg( cx, @@ -544,9 +545,8 @@ impl Types { "you seem to be trying to use `&Box<T>`. Consider using just `&T`", "try", format!( - "&{}{}{}", + "&{}{}", ltopt, - mutopt, &snippet_with_applicability(cx, inner.span, "..", &mut applicability) ), Applicability::Unspecified, diff --git a/tests/ui/borrow_box.rs b/tests/ui/borrow_box.rs index b30f7290ffe..1901de46ca8 100644 --- a/tests/ui/borrow_box.rs +++ b/tests/ui/borrow_box.rs @@ -4,6 +4,14 @@ #![allow(dead_code)] pub fn test1(foo: &mut Box<bool>) { + // Although this function could be changed to "&mut bool", + // avoiding the Box, mutable references to boxes are not + // flagged by this lint. + // + // This omission is intentional: By passing a mutable Box, + // the memory location of the pointed-to object could be + // modified. By passing a mutable reference, the contents + // could change, but not the location. println!("{:?}", foo) } @@ -71,6 +79,16 @@ impl<'a> Test12 for Test11<'a> { } } +pub fn test13(boxed_slice: &mut Box<[i32]>) { + // Unconditionally replaces the box pointer. + // + // This cannot be accomplished if "&mut [i32]" is passed, + // and provides a test case where passing a reference to + // a Box is valid. + let mut data = vec![12]; + *boxed_slice = data.into_boxed_slice(); +} + fn main() { test1(&mut Box::new(false)); test2(); diff --git a/tests/ui/borrow_box.stderr b/tests/ui/borrow_box.stderr index 89171ddd7c6..b5db691f89f 100644 --- a/tests/ui/borrow_box.stderr +++ b/tests/ui/borrow_box.stderr @@ -1,8 +1,8 @@ error: you seem to be trying to use `&Box<T>`. Consider using just `&T` - --> $DIR/borrow_box.rs:6:19 + --> $DIR/borrow_box.rs:19:14 | -LL | pub fn test1(foo: &mut Box<bool>) { - | ^^^^^^^^^^^^^^ help: try: `&mut bool` +LL | let foo: &Box<bool>; + | ^^^^^^^^^^ help: try: `&bool` | note: the lint level is defined here --> $DIR/borrow_box.rs:1:9 @@ -11,22 +11,16 @@ LL | #![deny(clippy::borrowed_box)] | ^^^^^^^^^^^^^^^^^^^^ error: you seem to be trying to use `&Box<T>`. Consider using just `&T` - --> $DIR/borrow_box.rs:11:14 - | -LL | let foo: &Box<bool>; - | ^^^^^^^^^^ help: try: `&bool` - -error: you seem to be trying to use `&Box<T>`. Consider using just `&T` - --> $DIR/borrow_box.rs:15:10 + --> $DIR/borrow_box.rs:23:10 | LL | foo: &'a Box<bool>, | ^^^^^^^^^^^^^ help: try: `&'a bool` error: you seem to be trying to use `&Box<T>`. Consider using just `&T` - --> $DIR/borrow_box.rs:19:17 + --> $DIR/borrow_box.rs:27:17 | LL | fn test4(a: &Box<bool>); | ^^^^^^^^^^ help: try: `&bool` -error: aborting due to 4 previous errors +error: aborting due to 3 previous errors |