mod borrowed_box;
-mod box_vec;
+mod box_collection;
mod linked_list;
mod option_option;
mod rc_buffer;
+mod rc_mutex;
mod redundant_allocation;
mod type_complexity;
mod utils;
use rustc_span::source_map::Span;
declare_clippy_lint! {
- /// **What it does:** Checks for use of `Box<Vec<_>>` anywhere in the code.
+ /// ### What it does
+ /// 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
+ /// ### Why is this bad?
+ /// 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.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// struct X {
/// values: Box<Vec<Foo>>,
/// 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"
}
declare_clippy_lint! {
- /// **What it does:** Checks for use of `Vec<Box<T>>` where T: Sized anywhere in the code.
+ /// ### What it does
+ /// Checks for use of `Vec<Box<T>>` where T: Sized 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
+ /// ### Why is this bad?
+ /// `Vec` already keeps its contents in a separate area on
/// the heap. So if you `Box` its contents, you just add another level of indirection.
///
- /// **Known problems:** Vec<Box<T: Sized>> makes sense if T is a large type (see [#3530](https://github.com/rust-lang/rust-clippy/issues/3530),
+ /// ### Known problems
+ /// Vec<Box<T: Sized>> makes sense if T is a large type (see [#3530](https://github.com/rust-lang/rust-clippy/issues/3530),
/// 1st comment).
///
- /// **Example:**
+ /// ### Example
/// ```rust
/// struct X {
/// values: Vec<Box<i32>>,
/// 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"
}
declare_clippy_lint! {
- /// **What it does:** Checks for use of `Option<Option<_>>` in function signatures and type
+ /// ### What it does
+ /// Checks for use of `Option<Option<_>>` in function signatures and type
/// definitions
///
- /// **Why is this bad?** `Option<_>` represents an optional value. `Option<Option<_>>`
+ /// ### Why is this bad?
+ /// `Option<_>` represents an optional value. `Option<Option<_>>`
/// represents an optional optional value which is logically the same thing as an optional
/// value but has an unneeded extra level of wrapping.
///
/// If you have a case where `Some(Some(_))`, `Some(None)` and `None` are distinct cases,
/// consider a custom `enum` instead, with clear names for each case.
///
- /// **Known problems:** None.
- ///
- /// **Example**
+ /// ### Example
/// ```rust
/// fn get_data() -> Option<Option<u32>> {
/// None
/// Contents::None
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub OPTION_OPTION,
pedantic,
"usage of `Option<Option<T>>`"
}
declare_clippy_lint! {
- /// **What it does:** Checks for usage of any `LinkedList`, suggesting to use a
+ /// ### What it does
+ /// Checks for usage of any `LinkedList`, suggesting to use a
/// `Vec` or a `VecDeque` (formerly called `RingBuf`).
///
- /// **Why is this bad?** Gankro says:
+ /// ### Why is this bad?
+ /// Gankro says:
///
/// > The TL;DR of `LinkedList` is that it's built on a massive amount of
/// pointers and indirection.
/// can still be better
/// > because of how expensive it is to seek to the middle of a `LinkedList`.
///
- /// **Known problems:** False positives – the instances where using a
+ /// ### Known problems
+ /// False positives – the instances where using a
/// `LinkedList` makes sense are few and far between, but they can still happen.
///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # 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`"
}
declare_clippy_lint! {
- /// **What it does:** Checks for use of `&Box<T>` anywhere in the code.
+ /// ### What it does
+ /// Checks for use of `&Box<T>` anywhere in the code.
/// Check the [Box documentation](https://doc.rust-lang.org/std/boxed/index.html) for more information.
///
- /// **Why is this bad?** Any `&Box<T>` can also be a `&T`, which is more
+ /// ### Why is this bad?
+ /// Any `&Box<T>` can also be a `&T`, which is more
/// general.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// fn foo(bar: &Box<T>) { ... }
/// ```
/// ```rust,ignore
/// fn foo(bar: &T) { ... }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub BORROWED_BOX,
complexity,
"a borrow of a boxed type"
}
declare_clippy_lint! {
- /// **What it does:** Checks for use of redundant allocations anywhere in the code.
+ /// ### What it does
+ /// Checks for use of redundant allocations anywhere in the code.
///
- /// **Why is this bad?** Expressions such as `Rc<&T>`, `Rc<Rc<T>>`, `Rc<Box<T>>`, `Box<&T>`
- /// add an unnecessary level of indirection.
+ /// ### Why is this bad?
+ /// Expressions such as `Rc<&T>`, `Rc<Rc<T>>`, `Rc<Arc<T>>`, `Rc<Box<T>>`, `Arc<&T>`, `Arc<Rc<T>>`,
+ /// `Arc<Arc<T>>`, `Arc<Box<T>>`, `Box<&T>`, `Box<Rc<T>>`, `Box<Arc<T>>`, `Box<Box<T>>`, add an unnecessary level of indirection.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # use std::rc::Rc;
/// fn foo(bar: Rc<&usize>) {}
/// ```rust
/// fn foo(bar: &usize) {}
/// ```
+ #[clippy::version = "1.44.0"]
pub REDUNDANT_ALLOCATION,
perf,
"redundant allocation"
}
declare_clippy_lint! {
- /// **What it does:** Checks for `Rc<T>` and `Arc<T>` when `T` is a mutable buffer type such as `String` or `Vec`.
+ /// ### What it does
+ /// Checks for `Rc<T>` and `Arc<T>` when `T` is a mutable buffer type such as `String` or `Vec`.
///
- /// **Why is this bad?** Expressions such as `Rc<String>` usually have no advantage over `Rc<str>`, since
+ /// ### Why is this bad?
+ /// Expressions such as `Rc<String>` usually have no advantage over `Rc<str>`, since
/// it is larger and involves an extra level of indirection, and doesn't implement `Borrow<str>`.
///
/// While mutating a buffer type would still be possible with `Rc::get_mut()`, it only
/// type with an interior mutable container (such as `RefCell` or `Mutex`) would normally
/// be used.
///
- /// **Known problems:** This pattern can be desirable to avoid the overhead of a `RefCell` or `Mutex` for
+ /// ### Known problems
+ /// This pattern can be desirable to avoid the overhead of a `RefCell` or `Mutex` for
/// cases where mutation only happens before there are any additional references.
///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// # use std::rc::Rc;
/// fn foo(interned: Rc<String>) { ... }
/// ```rust,ignore
/// fn foo(interned: Rc<str>) { ... }
/// ```
+ #[clippy::version = "1.48.0"]
pub RC_BUFFER,
restriction,
"shared ownership of a buffer type"
}
declare_clippy_lint! {
- /// **What it does:** Checks for types used in structs, parameters and `let`
+ /// ### What it does
+ /// Checks for types used in structs, parameters and `let`
/// declarations above a certain complexity threshold.
///
- /// **Why is this bad?** Too complex types make the code less readable. Consider
+ /// ### Why is this bad?
+ /// Too complex types make the code less readable. Consider
/// using a `type` definition to simplify them.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # use std::rc::Rc;
/// struct Foo {
/// 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"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for `Rc<Mutex<T>>`.
+ ///
+ /// ### Why is this bad?
+ /// `Rc` is used in single thread and `Mutex` is used in multi thread.
+ /// Consider using `Rc<RefCell<T>>` in single thread or `Arc<Mutex<T>>` in multi thread.
+ ///
+ /// ### Known problems
+ /// Sometimes combining generic types can lead to the requirement that a
+ /// type use Rc in conjunction with Mutex. We must consider those cases false positives, but
+ /// alas they are quite hard to rule out. Luckily they are also rare.
+ ///
+ /// ### Example
+ /// ```rust,ignore
+ /// use std::rc::Rc;
+ /// use std::sync::Mutex;
+ /// fn foo(interned: Rc<Mutex<i32>>) { ... }
+ /// ```
+ ///
+ /// Better:
+ ///
+ /// ```rust,ignore
+ /// use std::rc::Rc;
+ /// use std::cell::RefCell
+ /// fn foo(interned: Rc<RefCell<i32>>) { ... }
+ /// ```
+ #[clippy::version = "1.55.0"]
+ pub RC_MUTEX,
+ restriction,
+ "usage of `Rc<Mutex<T>>`"
+}
+
pub struct Types {
vec_box_size_threshold: u64,
type_complexity_threshold: u64,
+ avoid_breaking_exported_api: bool,
}
-impl_lint_pass!(Types => [BOX_VEC, VEC_BOX, OPTION_OPTION, LINKEDLIST, BORROWED_BOX, REDUNDANT_ALLOCATION, RC_BUFFER, 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) {
false
};
+ let is_exported = cx.access_levels.is_exported(cx.tcx.hir().local_def_id(id));
+
self.check_fn_decl(
cx,
decl,
CheckTyContext {
is_in_trait_impl,
+ is_exported,
..CheckTyContext::default()
},
);
}
fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
+ let is_exported = cx.access_levels.is_exported(item.def_id);
+
match item.kind {
- ItemKind::Static(ty, _, _) | ItemKind::Const(ty, _) => self.check_ty(cx, ty, CheckTyContext::default()),
+ ItemKind::Static(ty, _, _) | ItemKind::Const(ty, _) => self.check_ty(
+ cx,
+ ty,
+ CheckTyContext {
+ is_exported,
+ ..CheckTyContext::default()
+ },
+ ),
// functions, enums, structs, impls and traits are covered
_ => (),
}
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(..) => (),
}
}
fn check_field_def(&mut self, cx: &LateContext<'_>, field: &hir::FieldDef<'_>) {
- self.check_ty(cx, field.ty, CheckTyContext::default());
+ let is_exported = cx.access_levels.is_exported(cx.tcx.hir().local_def_id(field.hir_id));
+
+ self.check_ty(
+ cx,
+ field.ty,
+ CheckTyContext {
+ is_exported,
+ ..CheckTyContext::default()
+ },
+ );
}
- fn check_trait_item(&mut self, cx: &LateContext<'_>, item: &TraitItem<'_>) {
+ fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &TraitItem<'_>) {
+ let is_exported = cx.access_levels.is_exported(item.def_id);
+
+ let context = CheckTyContext {
+ is_exported,
+ ..CheckTyContext::default()
+ };
+
match item.kind {
TraitItemKind::Const(ty, _) | TraitItemKind::Type(_, Some(ty)) => {
- self.check_ty(cx, ty, CheckTyContext::default());
+ self.check_ty(cx, ty, context);
},
- TraitItemKind::Fn(ref sig, _) => self.check_fn_decl(cx, sig.decl, CheckTyContext::default()),
+ TraitItemKind::Fn(ref sig, _) => self.check_fn_decl(cx, sig.decl, context),
TraitItemKind::Type(..) => (),
}
}
}
impl Types {
- pub fn new(vec_box_size_threshold: u64, type_complexity_threshold: u64) -> Self {
+ pub fn new(vec_box_size_threshold: u64, type_complexity_threshold: u64, avoid_breaking_exported_api: bool) -> Self {
Self {
vec_box_size_threshold,
type_complexity_threshold,
+ avoid_breaking_exported_api,
}
}
let hir_id = hir_ty.hir_id;
let res = cx.qpath_res(qpath, hir_id);
if let Some(def_id) = res.opt_def_id() {
- let mut triggered = false;
- triggered |= box_vec::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);
- triggered |= option_option::check(cx, hir_ty, qpath, def_id);
- triggered |= linked_list::check(cx, hir_ty, def_id);
-
- if triggered {
- return;
+ if self.is_type_change_allowed(context) {
+ // All lints that are being checked in this block are guarded by
+ // the `avoid_breaking_exported_api` configuration. When adding a
+ // new lint, please also add the name to the configuration documentation
+ // in `clippy_lints::utils::conf.rs`
+
+ let mut triggered = false;
+ 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);
+ triggered |= option_option::check(cx, hir_ty, qpath, def_id);
+ triggered |= linked_list::check(cx, hir_ty, def_id);
+ triggered |= rc_mutex::check(cx, hir_ty, qpath, def_id);
+
+ if triggered {
+ return;
+ }
}
}
match *qpath {
_ => {},
}
}
+
+ /// This function checks if the type is allowed to change in the current context
+ /// based on the `avoid_breaking_exported_api` configuration
+ fn is_type_change_allowed(&self, context: CheckTyContext) -> bool {
+ !(context.is_exported && self.avoid_breaking_exported_api)
+ }
}
+#[allow(clippy::struct_excessive_bools)]
#[derive(Clone, Copy, Default)]
struct CheckTyContext {
is_in_trait_impl: bool,
+ /// `true` for types on local variables.
is_local: bool,
+ /// `true` for types that are part of the public API.
+ is_exported: bool,
is_nested_call: bool,
}
projects / rust.git / blobdiff