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5099ac24 FG |
1 | use clippy_utils::diagnostics::span_lint_and_sugg; |
2 | use clippy_utils::is_no_std_crate; | |
3 | use clippy_utils::source::snippet_opt; | |
4 | use clippy_utils::{meets_msrv, msrvs}; | |
5 | use if_chain::if_chain; | |
6 | use rustc_errors::Applicability; | |
7 | use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, TyKind}; | |
8 | use rustc_lint::{LateContext, LateLintPass}; | |
9 | use rustc_semver::RustcVersion; | |
10 | use rustc_session::{declare_tool_lint, impl_lint_pass}; | |
11 | ||
12 | declare_clippy_lint! { | |
13 | /// ### What it does | |
14 | /// Checks for the usage of `&expr as *const T` or | |
15 | /// `&mut expr as *mut T`, and suggest using `ptr::addr_of` or | |
16 | /// `ptr::addr_of_mut` instead. | |
17 | /// | |
18 | /// ### Why is this bad? | |
19 | /// This would improve readability and avoid creating a reference | |
20 | /// that points to an uninitialized value or unaligned place. | |
21 | /// Read the `ptr::addr_of` docs for more information. | |
22 | /// | |
23 | /// ### Example | |
24 | /// ```rust | |
25 | /// let val = 1; | |
26 | /// let p = &val as *const i32; | |
27 | /// | |
28 | /// let mut val_mut = 1; | |
29 | /// let p_mut = &mut val_mut as *mut i32; | |
30 | /// ``` | |
31 | /// Use instead: | |
32 | /// ```rust | |
33 | /// let val = 1; | |
34 | /// let p = std::ptr::addr_of!(val); | |
35 | /// | |
36 | /// let mut val_mut = 1; | |
37 | /// let p_mut = std::ptr::addr_of_mut!(val_mut); | |
38 | /// ``` | |
39 | #[clippy::version = "1.60.0"] | |
40 | pub BORROW_AS_PTR, | |
41 | pedantic, | |
42 | "borrowing just to cast to a raw pointer" | |
43 | } | |
44 | ||
45 | impl_lint_pass!(BorrowAsPtr => [BORROW_AS_PTR]); | |
46 | ||
47 | pub struct BorrowAsPtr { | |
48 | msrv: Option<RustcVersion>, | |
49 | } | |
50 | ||
51 | impl BorrowAsPtr { | |
52 | #[must_use] | |
53 | pub fn new(msrv: Option<RustcVersion>) -> Self { | |
54 | Self { msrv } | |
55 | } | |
56 | } | |
57 | ||
58 | impl<'tcx> LateLintPass<'tcx> for BorrowAsPtr { | |
59 | fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { | |
60 | if !meets_msrv(self.msrv.as_ref(), &msrvs::BORROW_AS_PTR) { | |
61 | return; | |
62 | } | |
63 | ||
64 | if expr.span.from_expansion() { | |
65 | return; | |
66 | } | |
67 | ||
68 | if_chain! { | |
69 | if let ExprKind::Cast(left_expr, ty) = &expr.kind; | |
70 | if let TyKind::Ptr(_) = ty.kind; | |
71 | if let ExprKind::AddrOf(BorrowKind::Ref, mutability, e) = &left_expr.kind; | |
72 | ||
73 | then { | |
74 | let core_or_std = if is_no_std_crate(cx) { "core" } else { "std" }; | |
75 | let macro_name = match mutability { | |
76 | Mutability::Not => "addr_of", | |
77 | Mutability::Mut => "addr_of_mut", | |
78 | }; | |
79 | ||
80 | span_lint_and_sugg( | |
81 | cx, | |
82 | BORROW_AS_PTR, | |
83 | expr.span, | |
84 | "borrow as raw pointer", | |
85 | "try", | |
86 | format!( | |
87 | "{}::ptr::{}!({})", | |
88 | core_or_std, | |
89 | macro_name, | |
90 | snippet_opt(cx, e.span).unwrap() | |
91 | ), | |
92 | Applicability::MachineApplicable, | |
93 | ); | |
94 | } | |
95 | } | |
96 | } | |
97 | ||
98 | extract_msrv_attr!(LateContext); | |
99 | } |