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KisaragiEffectiveKisaragiEffective
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fix: handle std::ptr::null{_mut}
close #11066 close #11665 close #11911
1 parent da27c97 commit 8eea8b1

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4 files changed

+426
-5
lines changed

4 files changed

+426
-5
lines changed

‎clippy_lints/src/casts/ptr_as_ptr.rs

+51-4
Original file line numberDiff line numberDiff line change
@@ -3,12 +3,29 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
33
use clippy_utils::source::snippet_with_applicability;
44
use clippy_utils::sugg::Sugg;
55
use rustc_errors::Applicability;
6-
use rustc_hir::{Expr, ExprKind, Mutability, TyKind};
6+
use rustc_hir::{Expr, ExprKind, Mutability, QPath, TyKind};
7+
use rustc_hir_pretty::qpath_to_string;
78
use rustc_lint::LateContext;
89
use rustc_middle::ty::{self, TypeAndMut};
10+
use rustc_span::sym;
911

1012
use super::PTR_AS_PTR;
1113

14+
enum OmitFollowedCastReason<'a> {
15+
None,
16+
Null(&'a QPath<'a>),
17+
NullMut(&'a QPath<'a>),
18+
}
19+
20+
impl OmitFollowedCastReason<'_> {
21+
fn corresponding_item(&self) -> Option<&QPath<'_>> {
22+
match self {
23+
OmitFollowedCastReason::None => None,
24+
OmitFollowedCastReason::Null(x) | OmitFollowedCastReason::NullMut(x) => Some(*x),
25+
}
26+
}
27+
}
28+
1229
pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, msrv: &Msrv) {
1330
if !msrv.meets(msrvs::POINTER_CAST) {
1431
return;
@@ -25,7 +42,6 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, msrv: &Msrv) {
2542
&& to_pointee_ty.is_sized(cx.tcx, cx.param_env)
2643
{
2744
let mut app = Applicability::MachineApplicable;
28-
let cast_expr_sugg = Sugg::hir_with_applicability(cx, cast_expr, "_", &mut app);
2945
let turbofish = match &cast_to_hir_ty.kind {
3046
TyKind::Infer => String::new(),
3147
TyKind::Ptr(mut_ty) => {
@@ -41,13 +57,44 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, msrv: &Msrv) {
4157
_ => return,
4258
};
4359

60+
// following `cast` does not compile because it fails to infer what type is expected
61+
// as type argument to `std::ptr::ptr_null` or `std::ptr::ptr_null_mut`, so
62+
// we omit following `cast`:
63+
let omit_cast = if let ExprKind::Call(func, []) = cast_expr.kind
64+
&& let ExprKind::Path(ref qpath @ QPath::Resolved(None, path)) = func.kind
65+
{
66+
let method_defid = path.res.def_id();
67+
if cx.tcx.is_diagnostic_item(sym::ptr_null, method_defid) {
68+
OmitFollowedCastReason::Null(qpath)
69+
} else if cx.tcx.is_diagnostic_item(sym::ptr_null_mut, method_defid) {
70+
OmitFollowedCastReason::NullMut(qpath)
71+
} else {
72+
OmitFollowedCastReason::None
73+
}
74+
} else {
75+
OmitFollowedCastReason::None
76+
};
77+
78+
let (help, final_suggestion) = if let Some(method) = omit_cast.corresponding_item() {
79+
// don't force absolute path
80+
let method = qpath_to_string(method);
81+
("try call directly", format!("{method}{turbofish}()"))
82+
} else {
83+
let cast_expr_sugg = Sugg::hir_with_applicability(cx, cast_expr, "_", &mut app);
84+
85+
(
86+
"try `pointer::cast`, a safer alternative",
87+
format!("{}.cast{turbofish}()", cast_expr_sugg.maybe_par()),
88+
)
89+
};
90+
4491
span_lint_and_sugg(
4592
cx,
4693
PTR_AS_PTR,
4794
expr.span,
4895
"`as` casting between raw pointers without changing its mutability",
49-
"try `pointer::cast`, a safer alternative",
50-
format!("{}.cast{turbofish}()", cast_expr_sugg.maybe_par()),
96+
help,
97+
final_suggestion,
5198
app,
5299
);
53100
}

‎tests/ui/ptr_as_ptr.fixed

+115
Original file line numberDiff line numberDiff line change
@@ -71,3 +71,118 @@ fn _msrv_1_38() {
7171
let _ = ptr.cast::<i32>();
7272
let _ = mut_ptr.cast::<i32>();
7373
}
74+
75+
#[allow(clippy::unnecessary_cast)]
76+
mod null {
77+
fn use_path_mut() -> *mut u32 {
78+
use std::ptr;
79+
ptr::null_mut::<u32>()
80+
}
81+
82+
fn full_path_mut() -> *mut u32 {
83+
std::ptr::null_mut::<u32>()
84+
}
85+
86+
fn core_path_mut() -> *mut u32 {
87+
use core::ptr;
88+
ptr::null_mut::<u32>()
89+
}
90+
91+
fn full_core_path_mut() -> *mut u32 {
92+
core::ptr::null_mut::<u32>()
93+
}
94+
95+
fn use_path() -> *const u32 {
96+
use std::ptr;
97+
ptr::null::<u32>()
98+
}
99+
100+
fn full_path() -> *const u32 {
101+
std::ptr::null::<u32>()
102+
}
103+
104+
fn core_path() -> *const u32 {
105+
use core::ptr;
106+
ptr::null::<u32>()
107+
}
108+
109+
fn full_core_path() -> *const u32 {
110+
core::ptr::null::<u32>()
111+
}
112+
}
113+
114+
mod null_ptr_infer {
115+
fn use_path_mut() -> *mut u32 {
116+
use std::ptr;
117+
ptr::null_mut()
118+
}
119+
120+
fn full_path_mut() -> *mut u32 {
121+
std::ptr::null_mut()
122+
}
123+
124+
fn core_path_mut() -> *mut u32 {
125+
use core::ptr;
126+
ptr::null_mut()
127+
}
128+
129+
fn full_core_path_mut() -> *mut u32 {
130+
core::ptr::null_mut()
131+
}
132+
133+
fn use_path() -> *const u32 {
134+
use std::ptr;
135+
ptr::null()
136+
}
137+
138+
fn full_path() -> *const u32 {
139+
std::ptr::null()
140+
}
141+
142+
fn core_path() -> *const u32 {
143+
use core::ptr;
144+
ptr::null()
145+
}
146+
147+
fn full_core_path() -> *const u32 {
148+
core::ptr::null()
149+
}
150+
}
151+
152+
mod null_entire_infer {
153+
fn use_path_mut() -> *mut u32 {
154+
use std::ptr;
155+
ptr::null_mut()
156+
}
157+
158+
fn full_path_mut() -> *mut u32 {
159+
std::ptr::null_mut()
160+
}
161+
162+
fn core_path_mut() -> *mut u32 {
163+
use core::ptr;
164+
ptr::null_mut()
165+
}
166+
167+
fn full_core_path_mut() -> *mut u32 {
168+
core::ptr::null_mut()
169+
}
170+
171+
fn use_path() -> *const u32 {
172+
use std::ptr;
173+
ptr::null()
174+
}
175+
176+
fn full_path() -> *const u32 {
177+
std::ptr::null()
178+
}
179+
180+
fn core_path() -> *const u32 {
181+
use core::ptr;
182+
ptr::null()
183+
}
184+
185+
fn full_core_path() -> *const u32 {
186+
core::ptr::null()
187+
}
188+
}

‎tests/ui/ptr_as_ptr.rs

+115
Original file line numberDiff line numberDiff line change
@@ -71,3 +71,118 @@ fn _msrv_1_38() {
7171
let _ = ptr as *const i32;
7272
let _ = mut_ptr as *mut i32;
7373
}
74+
75+
#[allow(clippy::unnecessary_cast)]
76+
mod null {
77+
fn use_path_mut() -> *mut u32 {
78+
use std::ptr;
79+
ptr::null_mut() as *mut u32
80+
}
81+
82+
fn full_path_mut() -> *mut u32 {
83+
std::ptr::null_mut() as *mut u32
84+
}
85+
86+
fn core_path_mut() -> *mut u32 {
87+
use core::ptr;
88+
ptr::null_mut() as *mut u32
89+
}
90+
91+
fn full_core_path_mut() -> *mut u32 {
92+
core::ptr::null_mut() as *mut u32
93+
}
94+
95+
fn use_path() -> *const u32 {
96+
use std::ptr;
97+
ptr::null() as *const u32
98+
}
99+
100+
fn full_path() -> *const u32 {
101+
std::ptr::null() as *const u32
102+
}
103+
104+
fn core_path() -> *const u32 {
105+
use core::ptr;
106+
ptr::null() as *const u32
107+
}
108+
109+
fn full_core_path() -> *const u32 {
110+
core::ptr::null() as *const u32
111+
}
112+
}
113+
114+
mod null_ptr_infer {
115+
fn use_path_mut() -> *mut u32 {
116+
use std::ptr;
117+
ptr::null_mut() as *mut _
118+
}
119+
120+
fn full_path_mut() -> *mut u32 {
121+
std::ptr::null_mut() as *mut _
122+
}
123+
124+
fn core_path_mut() -> *mut u32 {
125+
use core::ptr;
126+
ptr::null_mut() as *mut _
127+
}
128+
129+
fn full_core_path_mut() -> *mut u32 {
130+
core::ptr::null_mut() as *mut _
131+
}
132+
133+
fn use_path() -> *const u32 {
134+
use std::ptr;
135+
ptr::null() as *const _
136+
}
137+
138+
fn full_path() -> *const u32 {
139+
std::ptr::null() as *const _
140+
}
141+
142+
fn core_path() -> *const u32 {
143+
use core::ptr;
144+
ptr::null() as *const _
145+
}
146+
147+
fn full_core_path() -> *const u32 {
148+
core::ptr::null() as *const _
149+
}
150+
}
151+
152+
mod null_entire_infer {
153+
fn use_path_mut() -> *mut u32 {
154+
use std::ptr;
155+
ptr::null_mut() as _
156+
}
157+
158+
fn full_path_mut() -> *mut u32 {
159+
std::ptr::null_mut() as _
160+
}
161+
162+
fn core_path_mut() -> *mut u32 {
163+
use core::ptr;
164+
ptr::null_mut() as _
165+
}
166+
167+
fn full_core_path_mut() -> *mut u32 {
168+
core::ptr::null_mut() as _
169+
}
170+
171+
fn use_path() -> *const u32 {
172+
use std::ptr;
173+
ptr::null() as _
174+
}
175+
176+
fn full_path() -> *const u32 {
177+
std::ptr::null() as _
178+
}
179+
180+
fn core_path() -> *const u32 {
181+
use core::ptr;
182+
ptr::null() as _
183+
}
184+
185+
fn full_core_path() -> *const u32 {
186+
core::ptr::null() as _
187+
}
188+
}

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