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::source::snippet_with_applicability;
   3 use clippy_utils::{match_def_path, meets_msrv, msrvs, paths};
   4 use if_chain::if_chain;
   5 use rustc_errors::Applicability;
   6 use rustc_hir::{def_id::DefId, Expr, ExprKind};
   7 use rustc_lint::LateContext;
   8 use rustc_middle::ty::{self, Ty};
   9 use rustc_semver::RustcVersion;
  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(
  29     cx: &LateContext<'_>,
  30     expr: &Expr<'_>,
  31     cast_expr: &Expr<'_>,
  32     cast_to: Ty<'_>,
  33     msrv: Option<RustcVersion>,
  34 ) {
  35     if_chain! {
  36         if meets_msrv(msrv, msrvs::PTR_SLICE_RAW_PARTS);
  37         if let ty::RawPtr(ptrty) = cast_to.kind();
  38         if let ty::Slice(_) = ptrty.ty.kind();
  39         if let ExprKind::Call(fun, [ptr_arg, len_arg]) = cast_expr.peel_blocks().kind;
  40         if let ExprKind::Path(ref qpath) = fun.kind;
  41         if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
  42         if let Some(rpk) = raw_parts_kind(cx, fun_def_id);
  43         then {
  44             let func = match rpk {
  45                 RawPartsKind::Immutable => "from_raw_parts",
  46                 RawPartsKind::Mutable => "from_raw_parts_mut"
  47             };
  48             let span = expr.span;
  49             let mut applicability = Applicability::MachineApplicable;
  50             let ptr = snippet_with_applicability(cx, ptr_arg.span, "ptr", &mut applicability);
  51             let len = snippet_with_applicability(cx, len_arg.span, "len", &mut applicability);
  52             span_lint_and_sugg(
  53                 cx,
  54                 CAST_SLICE_FROM_RAW_PARTS,
  55                 span,
  56                 &format!("casting the result of `{func}` to {cast_to}"),
  57                 "replace with",
  58                 format!("core::ptr::slice_{func}({ptr}, {len})"),
  59                 applicability
  60             );
  61         }
  62     }
  63 }