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| 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 | +} |
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