src/tools/clippy/clippy_lints/src/casts/cast_slice_from_raw_parts.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::msrvs::{self, Msrv};
   3 use clippy_utils::source::snippet_with_applicability;
   4 use clippy_utils::{match_def_path, paths};
   5 use if_chain::if_chain;
   6 use rustc_errors::Applicability;
   7 use rustc_hir::{def_id::DefId, Expr, ExprKind};
   8 use rustc_lint::LateContext;
   9 use rustc_middle::ty::{self, Ty};
  10
  11 use super::CAST_SLICE_FROM_RAW_PARTS;
  12
  13 enum RawPartsKind {
  14     Immutable,
  15     Mutable,
  16 }
  17
  18 fn raw_parts_kind(cx: &LateContext<'_>, did: DefId) -> Option<RawPartsKind> {
  19     if match_def_path(cx, did, &paths::SLICE_FROM_RAW_PARTS) {
  20         Some(RawPartsKind::Immutable)
  21     } else if match_def_path(cx, did, &paths::SLICE_FROM_RAW_PARTS_MUT) {
  22         Some(RawPartsKind::Mutable)
  23     } else {
  24         None
  25     }
  26 }
  27
  28 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>, cast_to: Ty<'_>, msrv: &Msrv) {
  29     if_chain! {
  30         if msrv.meets(msrvs::PTR_SLICE_RAW_PARTS);
  31         if let ty::RawPtr(ptrty) = cast_to.kind();
  32         if let ty::Slice(_) = ptrty.ty.kind();
  33         if let ExprKind::Call(fun, [ptr_arg, len_arg]) = cast_expr.peel_blocks().kind;
  34         if let ExprKind::Path(ref qpath) = fun.kind;
  35         if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
  36         if let Some(rpk) = raw_parts_kind(cx, fun_def_id);
  37         then {
  38             let func = match rpk {
  39                 RawPartsKind::Immutable => "from_raw_parts",
  40                 RawPartsKind::Mutable => "from_raw_parts_mut"
  41             };
  42             let span = expr.span;
  43             let mut applicability = Applicability::MachineApplicable;
  44             let ptr = snippet_with_applicability(cx, ptr_arg.span, "ptr", &mut applicability);
  45             let len = snippet_with_applicability(cx, len_arg.span, "len", &mut applicability);
  46             span_lint_and_sugg(
  47                 cx,
  48                 CAST_SLICE_FROM_RAW_PARTS,
  49                 span,
  50                 &format!("casting the result of `{func}` to {cast_to}"),
  51                 "replace with",
  52                 format!("core::ptr::slice_{func}({ptr}, {len})"),
  53                 applicability
  54             );
  55         }
  56     }
  57 }