Mirrors/rust-clippy
2
0
Fork 0
mirror of https://github.com/rust-lang/rust-clippy synced 2024-11-22 20:53:21 +00:00
Code Issues Projects Releases Packages Wiki Activity

implement manual_partial_ord_impl

Browse source 
first try at this
This commit is contained in:
Centri3 2023-05-15 16:50:28 -05:00 committed by Catherine
parent 3a1fc26665
commit 2a1fd22f81
6 changed files with 220 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
CHANGELOG.md
View file

@ -4921,6 +4921,7 @@ Released 2018-09-13
[`manual_next_back`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_next_back
[`manual_non_exhaustive`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_non_exhaustive
[`manual_ok_or`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_ok_or
[`manual_partial_ord_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_partial_ord_impl
[`manual_range_contains`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_range_contains
[`manual_range_patterns`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_range_patterns
[`manual_rem_euclid`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_rem_euclid

1
clippy_lints/src/declared_lints.rs
View file

@ -277,6 +277,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
crate::manual_let_else::MANUAL_LET_ELSE_INFO,
crate::manual_main_separator_str::MANUAL_MAIN_SEPARATOR_STR_INFO,
crate::manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE_INFO,
crate::manual_partial_ord_impl::MANUAL_PARTIAL_ORD_IMPL_INFO,
crate::manual_range_patterns::MANUAL_RANGE_PATTERNS_INFO,
crate::manual_rem_euclid::MANUAL_REM_EUCLID_INFO,
crate::manual_retain::MANUAL_RETAIN_INFO,

1
clippy_lints/src/lib.rs
View file

@ -188,6 +188,7 @@ mod manual_is_ascii_check;
mod manual_let_else;
mod manual_main_separator_str;
mod manual_non_exhaustive;
mod manual_partial_ord_impl;
mod manual_range_patterns;
mod manual_rem_euclid;
mod manual_retain;

132
clippy_lints/src/manual_partial_ord_impl.rs Normal file
View file

@ -0,0 +1,132 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::{
def_path_def_ids, diagnostics::span_lint_and_sugg, get_trait_def_id, match_def_path, path_res, ty::implements_trait,
};
use rustc_errors::Applicability;
use rustc_hir::def::Res;
use rustc_hir::*;
use rustc_hir_analysis::hir_ty_to_ty;
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::def_id::DefId;
use std::cell::OnceCell;
declare_clippy_lint! {
/// ### What it does
/// Checks for manual implementations of both `PartialOrd` and `Ord` when only `Ord` is
/// necessary.
///
/// ### Why is this bad?
/// If both `PartialOrd` and `Ord` are implemented, `PartialOrd` will wrap the returned value of
/// `Ord::cmp` in `Some`. Not doing this may silently introduce an error.
///
/// ### Example
/// ```rust
/// #[derive(Eq, PartialEq)]
/// struct A(u32);
///
/// impl Ord for A {
/// fn cmp(&self, other: &Self) -> Ordering {
/// todo!();
/// }
/// }
///
/// impl PartialOrd for A {
/// fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
/// todo!();
/// }
/// }
/// ```
/// Use instead:
/// ```rust
/// #[derive(Eq, PartialEq)]
/// struct A(u32);
///
/// impl Ord for A {
/// fn cmp(&self, other: &Self) -> Ordering {
/// todo!();
/// }
/// }
///
/// impl PartialOrd for A {
/// fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
/// Some(self.cmp(other))
/// }
/// }
/// ```
#[clippy::version = "1.71.0"]
pub MANUAL_PARTIAL_ORD_IMPL,
nursery,
"default lint description"
}
impl_lint_pass!(ManualPartialOrdImpl => [MANUAL_PARTIAL_ORD_IMPL]);
#[derive(Clone)]
pub struct ManualPartialOrdImpl {
pub ord_def_id: OnceCell<DefId>,
}
impl LateLintPass<'_> for ManualPartialOrdImpl {
fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
if_chain! {
if let ItemKind::Impl(imp) = &item.kind;
if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id);
if cx.tcx.is_diagnostic_item(sym!(PartialOrd), impl_trait_ref.skip_binder().def_id);
then {
lint_impl_body(self, cx, imp, item);
}
}
}
}
fn lint_impl_body(conf: &mut ManualPartialOrdImpl, cx: &LateContext<'_>, imp: &Impl<'_>, item: &Item<'_>) {
for imp_item in imp.items {
if_chain! {
if imp_item.ident.name == sym!(partial_cmp);
if let ImplItemKind::Fn(_, id) = cx.tcx.hir().impl_item(imp_item.id).kind;
then {
let body = cx.tcx.hir().body(id);
let ord_def_id = conf.ord_def_id.get_or_init(|| get_trait_def_id(cx, &["core", "cmp", "Ord"]).unwrap());
if let ExprKind::Block(block, ..)
= body.value.kind && implements_trait(cx, hir_ty_to_ty(cx.tcx, imp.self_ty), *ord_def_id, &[])
{
if_chain! {
if block.stmts.is_empty();
if let Some(expr) = block.expr;
if let ExprKind::Call(Expr { kind: ExprKind::Path(path), ..}, [cmp_expr]) = expr.kind;
if let QPath::Resolved(_, some_path) = path;
if let Some(some_seg_one) = some_path.segments.get(0);
if some_seg_one.ident.name == sym!(Some);
if let ExprKind::MethodCall(cmp_path, _, [other_expr], ..) = cmp_expr.kind;
if cmp_path.ident.name == sym!(cmp);
if let Res::Local(..) = path_res(cx, other_expr);
then {}
else {
span_lint_and_then(
cx,
MANUAL_PARTIAL_ORD_IMPL,
item.span,
"manual implementation of `PartialOrd` when `Ord` is already implemented",
|diag| {
if let Some(param) = body.params.get(1)
&& let PatKind::Binding(_, _, param_ident, ..) = param.pat.kind
{
diag.span_suggestion(
block.span,
"change this to",
format!("{{ Some(self.cmp({})) }}",
param_ident.name),
Applicability::MaybeIncorrect
);
} else {
diag.help("return the value of `self.cmp` wrapped in `Some` instead");
};
}
);
}
}
}
}
}
}
}

57
tests/ui/manual_partial_ord_impl.rs Normal file
View file

@ -0,0 +1,57 @@
#![allow(unused)]
#![warn(clippy::manual_partial_ord_impl)]
#![no_main]
use std::cmp::Ordering;
// lint
#[derive(Eq, PartialEq)]
struct A(u32);
impl Ord for A {
fn cmp(&self, other: &Self) -> Ordering {
todo!();
}
}
impl PartialOrd for A {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
todo!();
}
}
// do not lint
#[derive(Eq, PartialEq)]
struct B(u32);
impl Ord for B {
fn cmp(&self, other: &Self) -> Ordering {
todo!();
}
}
impl PartialOrd for B {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
// lint, but we cannot give a suggestion since &Self is not named
#[derive(Eq, PartialEq)]
struct C(u32);
impl Ord for C {
fn cmp(&self, other: &Self) -> Ordering {
todo!();
}
}
impl PartialOrd for C {
fn partial_cmp(&self, _: &Self) -> Option<Ordering> {
todo!();
}
}

28
tests/ui/manual_partial_ord_impl.stderr Normal file
View file

@ -0,0 +1,28 @@
error: manual implementation of `PartialOrd` when `Ord` is already implemented
--> $DIR/manual_partial_ord_impl.rs:18:1
|
LL | / impl PartialOrd for A {
LL | | fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
| | _____________________________________________________________-
LL | || todo!();
LL | || }
| ||_____- help: change this to: `{ Some(self.cmp(other)) }`
LL | | }
| |__^
|
= note: `-D clippy::manual-partial-ord-impl` implied by `-D warnings`
error: manual implementation of `PartialOrd` when `Ord` is already implemented
--> $DIR/manual_partial_ord_impl.rs:52:1
|
LL | / impl PartialOrd for C {
LL | | fn partial_cmp(&self, _: &Self) -> Option<Ordering> {
LL | | todo!();
LL | | }
LL | | }
| |_^
|
= help: return the value of `self.cmp` wrapped in `Some` instead
error: aborting due to 2 previous errors