disable indexing_slicing for custom Index impls

This commit is contained in:
Jacherr 2024-03-15 00:04:27 +00:00 committed by Jacher
parent 03654badfd
commit 93b39d8910
5 changed files with 80 additions and 47 deletions

View file

@ -3,6 +3,7 @@
use clippy_utils::consts::{constant, Constant};
use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
use clippy_utils::higher;
use clippy_utils::ty::{adt_has_inherent_method, deref_chain};
use rustc_ast::ast::RangeLimits;
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
@ -104,7 +105,15 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
return;
}
if let ExprKind::Index(array, index, _) = &expr.kind {
if let ExprKind::Index(array, index, _) = &expr.kind
&& let expr_ty = cx.typeck_results().expr_ty(array)
&& let mut deref = deref_chain(cx, expr_ty)
&& deref.any(|l| {
l.peel_refs().is_slice()
|| l.peel_refs().is_array()
|| adt_has_inherent_method(cx, l.peel_refs(), sym!(get))
})
{
let note = "the suggestion might not be applicable in constant blocks";
let ty = cx.typeck_results().expr_ty(array).peel_refs();
if let Some(range) = higher::Range::hir(index) {

View file

@ -1,7 +1,7 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::get_parent_as_impl;
use clippy_utils::source::snippet;
use clippy_utils::ty::{implements_trait, make_normalized_projection};
use clippy_utils::ty::{adt_has_inherent_method, deref_chain, implements_trait, make_normalized_projection};
use rustc_ast::Mutability;
use rustc_errors::Applicability;
use rustc_hir::{FnRetTy, ImplItemKind, ImplicitSelfKind, ItemKind, TyKind};
@ -9,8 +9,7 @@ use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty::{self, Ty};
use rustc_session::declare_lint_pass;
use rustc_span::{sym, Symbol};
use std::iter;
use rustc_span::sym;
declare_clippy_lint! {
/// ### What it does
@ -124,33 +123,6 @@ fn is_ty_exported(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
.is_some_and(|did| cx.effective_visibilities.is_exported(did))
}
/// Returns the deref chain of a type, starting with the type itself.
fn deref_chain<'cx, 'tcx>(cx: &'cx LateContext<'tcx>, ty: Ty<'tcx>) -> impl Iterator<Item = Ty<'tcx>> + 'cx {
iter::successors(Some(ty), |&ty| {
if let Some(deref_did) = cx.tcx.lang_items().deref_trait()
&& implements_trait(cx, ty, deref_did, &[])
{
make_normalized_projection(cx.tcx, cx.param_env, deref_did, sym::Target, [ty])
} else {
None
}
})
}
fn adt_has_inherent_method(cx: &LateContext<'_>, ty: Ty<'_>, method_name: Symbol) -> bool {
if let Some(ty_did) = ty.ty_adt_def().map(ty::AdtDef::did) {
cx.tcx.inherent_impls(ty_did).into_iter().flatten().any(|&did| {
cx.tcx
.associated_items(did)
.filter_by_name_unhygienic(method_name)
.next()
.is_some_and(|item| item.kind == ty::AssocKind::Fn)
})
} else {
false
}
}
impl LateLintPass<'_> for IterWithoutIntoIter {
fn check_item(&mut self, cx: &LateContext<'_>, item: &rustc_hir::Item<'_>) {
if !in_external_macro(cx.sess(), item.span)

View file

@ -1328,3 +1328,33 @@ pub fn normalize_with_regions<'tcx>(tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>
pub fn is_manually_drop(ty: Ty<'_>) -> bool {
ty.ty_adt_def().map_or(false, AdtDef::is_manually_drop)
}
/// Returns the deref chain of a type, starting with the type itself.
pub fn deref_chain<'cx, 'tcx>(cx: &'cx LateContext<'tcx>, ty: Ty<'tcx>) -> impl Iterator<Item = Ty<'tcx>> + 'cx {
iter::successors(Some(ty), |&ty| {
if let Some(deref_did) = cx.tcx.lang_items().deref_trait()
&& implements_trait(cx, ty, deref_did, &[])
{
make_normalized_projection(cx.tcx, cx.param_env, deref_did, sym::Target, [ty])
} else {
None
}
})
}
/// Checks if a Ty<'_> has some inherent method Symbol.
/// This does not look for impls in the type's Deref::Target type.
/// If you need this, you should wrap this call in clippy_utils::ty::deref_chain().any(...).
pub fn adt_has_inherent_method(cx: &LateContext<'_>, ty: Ty<'_>, method_name: Symbol) -> bool {
if let Some(ty_did) = ty.ty_adt_def().map(ty::AdtDef::did) {
cx.tcx.inherent_impls(ty_did).into_iter().flatten().any(|&did| {
cx.tcx
.associated_items(did)
.filter_by_name_unhygienic(method_name)
.next()
.is_some_and(|item| item.kind == ty::AssocKind::Fn)
})
} else {
false
}
}

View file

@ -3,6 +3,21 @@
// we want to avoid false positives.
#![warn(clippy::out_of_bounds_indexing)]
#![allow(clippy::no_effect, clippy::unnecessary_operation, clippy::useless_vec)]
#![warn(clippy::indexing_slicing)]
use std::ops::Index;
struct BoolMap<T> {
false_value: T,
true_value: T,
}
impl<T> Index<bool> for BoolMap<T> {
type Output = T;
fn index(&self, index: bool) -> &T {
if index { &self.true_value } else { &self.false_value }
}
}
fn main() {
let x = [1, 2, 3, 4];
@ -51,4 +66,11 @@ fn main() {
//~^ ERROR: slicing may panic
&v[..]; // Ok, should not produce stderr.
let map = BoolMap {
false_value: 2,
true_value: 4,
};
map[true]; // Ok, because `get` does not exist (custom indexing)
}

View file

@ -1,5 +1,5 @@
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:12:6
--> tests/ui/indexing_slicing_slice.rs:27:6
|
LL | &x[index..];
| ^^^^^^^^^^
@ -9,7 +9,7 @@ LL | &x[index..];
= help: to override `-D warnings` add `#[allow(clippy::indexing_slicing)]`
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:14:6
--> tests/ui/indexing_slicing_slice.rs:29:6
|
LL | &x[..index];
| ^^^^^^^^^^
@ -17,7 +17,7 @@ LL | &x[..index];
= help: consider using `.get(..n)`or `.get_mut(..n)` instead
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:16:6
--> tests/ui/indexing_slicing_slice.rs:31:6
|
LL | &x[index_from..index_to];
| ^^^^^^^^^^^^^^^^^^^^^^^
@ -25,7 +25,7 @@ LL | &x[index_from..index_to];
= help: consider using `.get(n..m)` or `.get_mut(n..m)` instead
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:18:6
--> tests/ui/indexing_slicing_slice.rs:33:6
|
LL | &x[index_from..][..index_to];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -33,7 +33,7 @@ LL | &x[index_from..][..index_to];
= help: consider using `.get(..n)`or `.get_mut(..n)` instead
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:18:6
--> tests/ui/indexing_slicing_slice.rs:33:6
|
LL | &x[index_from..][..index_to];
| ^^^^^^^^^^^^^^^
@ -41,7 +41,7 @@ LL | &x[index_from..][..index_to];
= help: consider using `.get(n..)` or .get_mut(n..)` instead
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:21:6
--> tests/ui/indexing_slicing_slice.rs:36:6
|
LL | &x[5..][..10];
| ^^^^^^^^^^^^
@ -49,7 +49,7 @@ LL | &x[5..][..10];
= help: consider using `.get(..n)`or `.get_mut(..n)` instead
error: range is out of bounds
--> tests/ui/indexing_slicing_slice.rs:21:8
--> tests/ui/indexing_slicing_slice.rs:36:8
|
LL | &x[5..][..10];
| ^
@ -58,7 +58,7 @@ LL | &x[5..][..10];
= help: to override `-D warnings` add `#[allow(clippy::out_of_bounds_indexing)]`
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:25:6
--> tests/ui/indexing_slicing_slice.rs:40:6
|
LL | &x[0..][..3];
| ^^^^^^^^^^^
@ -66,7 +66,7 @@ LL | &x[0..][..3];
= help: consider using `.get(..n)`or `.get_mut(..n)` instead
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:27:6
--> tests/ui/indexing_slicing_slice.rs:42:6
|
LL | &x[1..][..5];
| ^^^^^^^^^^^
@ -74,19 +74,19 @@ LL | &x[1..][..5];
= help: consider using `.get(..n)`or `.get_mut(..n)` instead
error: range is out of bounds
--> tests/ui/indexing_slicing_slice.rs:35:12
--> tests/ui/indexing_slicing_slice.rs:50:12
|
LL | &y[0..=4];
| ^
error: range is out of bounds
--> tests/ui/indexing_slicing_slice.rs:37:11
--> tests/ui/indexing_slicing_slice.rs:52:11
|
LL | &y[..=4];
| ^
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:43:6
--> tests/ui/indexing_slicing_slice.rs:58:6
|
LL | &v[10..100];
| ^^^^^^^^^^
@ -94,7 +94,7 @@ LL | &v[10..100];
= help: consider using `.get(n..m)` or `.get_mut(n..m)` instead
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:45:6
--> tests/ui/indexing_slicing_slice.rs:60:6
|
LL | &x[10..][..100];
| ^^^^^^^^^^^^^^
@ -102,13 +102,13 @@ LL | &x[10..][..100];
= help: consider using `.get(..n)`or `.get_mut(..n)` instead
error: range is out of bounds
--> tests/ui/indexing_slicing_slice.rs:45:8
--> tests/ui/indexing_slicing_slice.rs:60:8
|
LL | &x[10..][..100];
| ^^
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:48:6
--> tests/ui/indexing_slicing_slice.rs:63:6
|
LL | &v[10..];
| ^^^^^^^
@ -116,7 +116,7 @@ LL | &v[10..];
= help: consider using `.get(n..)` or .get_mut(n..)` instead
error: slicing may panic
--> tests/ui/indexing_slicing_slice.rs:50:6
--> tests/ui/indexing_slicing_slice.rs:65:6
|
LL | &v[..100];
| ^^^^^^^^