1 use super::TRANSMUTE_PTR_TO_REF;
2 use clippy_utils::diagnostics::span_lint_and_then;
3 use clippy_utils::source::snippet_with_applicability;
4 use clippy_utils::{meets_msrv, msrvs, sugg};
5 use rustc_errors::Applicability;
6 use rustc_hir::{self as hir, Expr, GenericArg, Mutability, Path, TyKind};
7 use rustc_lint::LateContext;
8 use rustc_middle::ty::{self, Ty, TypeVisitable};
9 use rustc_semver::RustcVersion;
11 /// Checks for `transmute_ptr_to_ref` lint.
12 /// Returns `true` if it's triggered, otherwise returns `false`.
13 pub(super) fn check<'tcx>(
14 cx: &LateContext<'tcx>,
20 msrv: Option<RustcVersion>,
22 match (&from_ty.kind(), &to_ty.kind()) {
23 (ty::RawPtr(from_ptr_ty), ty::Ref(_, to_ref_ty, mutbl)) => {
29 "transmute from a pointer type (`{}`) to a reference type (`{}`)",
33 let arg = sugg::Sugg::hir(cx, arg, "..");
34 let (deref, cast) = if *mutbl == Mutability::Mut {
39 let mut app = Applicability::MachineApplicable;
41 let sugg = if let Some(ty) = get_explicit_type(path) {
42 let ty_snip = snippet_with_applicability(cx, ty.span, "..", &mut app);
43 if meets_msrv(msrv, msrvs::POINTER_CAST) {
44 format!("{}{}.cast::<{}>()", deref, arg.maybe_par(), ty_snip)
45 } else if from_ptr_ty.has_erased_regions() {
46 sugg::make_unop(deref, arg.as_ty(format!("{} () as {} {}", cast, cast, ty_snip)))
49 sugg::make_unop(deref, arg.as_ty(format!("{} {}", cast, ty_snip))).to_string()
51 } else if from_ptr_ty.ty == *to_ref_ty {
52 if from_ptr_ty.has_erased_regions() {
53 if meets_msrv(msrv, msrvs::POINTER_CAST) {
54 format!("{}{}.cast::<{}>()", deref, arg.maybe_par(), to_ref_ty)
56 sugg::make_unop(deref, arg.as_ty(format!("{} () as {} {}", cast, cast, to_ref_ty)))
60 sugg::make_unop(deref, arg).to_string()
63 sugg::make_unop(deref, arg.as_ty(format!("{} {}", cast, to_ref_ty))).to_string()
66 diag.span_suggestion(e.span, "try", sugg, app);
75 /// Gets the type `Bar` in `…::transmute<Foo, &Bar>`.
76 fn get_explicit_type<'tcx>(path: &'tcx Path<'tcx>) -> Option<&'tcx hir::Ty<'tcx>> {
77 if let GenericArg::Type(ty) = path.segments.last()?.args?.args.get(1)?
78 && let TyKind::Rptr(_, ty) = &ty.kind