mod borrowed_box;
-mod box_vec;
+mod box_collection;
mod linked_list;
mod option_option;
mod rc_buffer;
declare_clippy_lint! {
/// ### What it does
- /// Checks for use of `Box<Vec<_>>` anywhere in the code.
+ /// Checks for use of `Box<T>` where T is a collection such as Vec anywhere in the code.
/// Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
///
/// ### Why is this bad?
- /// `Vec` already keeps its contents in a separate area on
- /// the heap. So if you `Box` it, you just add another level of indirection
+ /// Collections already keeps their contents in a separate area on
+ /// the heap. So if you `Box` them, you just add another level of indirection
/// without any benefit whatsoever.
///
/// ### Example
/// values: Vec<Foo>,
/// }
/// ```
- pub BOX_VEC,
+ #[clippy::version = "1.57.0"]
+ pub BOX_COLLECTION,
perf,
"usage of `Box<Vec<T>>`, vector elements are already on the heap"
}
/// values: Vec<i32>,
/// }
/// ```
+ #[clippy::version = "1.33.0"]
pub VEC_BOX,
complexity,
"usage of `Vec<Box<T>>` where T: Sized, vector elements are already on the heap"
/// Contents::None
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub OPTION_OPTION,
pedantic,
"usage of `Option<Option<T>>`"
/// # use std::collections::LinkedList;
/// let x: LinkedList<usize> = LinkedList::new();
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub LINKEDLIST,
pedantic,
"usage of LinkedList, usually a vector is faster, or a more specialized data structure like a `VecDeque`"
/// ```rust,ignore
/// fn foo(bar: &T) { ... }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub BORROWED_BOX,
complexity,
"a borrow of a boxed type"
/// ```rust
/// fn foo(bar: &usize) {}
/// ```
+ #[clippy::version = "1.44.0"]
pub REDUNDANT_ALLOCATION,
perf,
"redundant allocation"
/// ```rust,ignore
/// fn foo(interned: Rc<str>) { ... }
/// ```
+ #[clippy::version = "1.48.0"]
pub RC_BUFFER,
restriction,
"shared ownership of a buffer type"
/// inner: Rc<Vec<Vec<Box<(u32, u32, u32, u32)>>>>,
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub TYPE_COMPLEXITY,
complexity,
"usage of very complex types that might be better factored into `type` definitions"
/// use std::cell::RefCell
/// fn foo(interned: Rc<RefCell<i32>>) { ... }
/// ```
+ #[clippy::version = "1.55.0"]
pub RC_MUTEX,
restriction,
"usage of `Rc<Mutex<T>>`"
avoid_breaking_exported_api: bool,
}
-impl_lint_pass!(Types => [BOX_VEC, VEC_BOX, OPTION_OPTION, LINKEDLIST, BORROWED_BOX, REDUNDANT_ALLOCATION, RC_BUFFER, RC_MUTEX, TYPE_COMPLEXITY]);
+impl_lint_pass!(Types => [BOX_COLLECTION, VEC_BOX, OPTION_OPTION, LINKEDLIST, BORROWED_BOX, REDUNDANT_ALLOCATION, RC_BUFFER, RC_MUTEX, TYPE_COMPLEXITY]);
impl<'tcx> LateLintPass<'tcx> for Types {
fn check_fn(&mut self, cx: &LateContext<'_>, _: FnKind<'_>, decl: &FnDecl<'_>, _: &Body<'_>, _: Span, id: HirId) {
fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>) {
match item.kind {
- ImplItemKind::Const(ty, _) | ImplItemKind::TyAlias(ty) => self.check_ty(
+ ImplItemKind::Const(ty, _) => self.check_ty(
cx,
ty,
CheckTyContext {
..CheckTyContext::default()
},
),
- // methods are covered by check_fn
- ImplItemKind::Fn(..) => (),
+ // Methods are covered by check_fn.
+ // Type aliases are ignored because oftentimes it's impossible to
+ // make type alias declaration in trait simpler, see #1013
+ ImplItemKind::Fn(..) | ImplItemKind::TyAlias(..) => (),
}
}
// in `clippy_lints::utils::conf.rs`
let mut triggered = false;
- triggered |= box_vec::check(cx, hir_ty, qpath, def_id);
+ triggered |= box_collection::check(cx, hir_ty, qpath, def_id);
triggered |= redundant_allocation::check(cx, hir_ty, qpath, def_id);
triggered |= rc_buffer::check(cx, hir_ty, qpath, def_id);
triggered |= vec_box::check(cx, hir_ty, qpath, def_id, self.vec_box_size_threshold);