2 use rustc_hir_analysis::check::{
3 cast::{self, CastCheckResult},
6 use rustc_lint::LateContext;
7 use rustc_middle::ty::{cast::CastKind, Ty};
8 use rustc_span::DUMMY_SP;
10 // check if the component types of the transmuted collection and the result have different ABI,
12 pub(super) fn is_layout_incompatible<'tcx>(cx: &LateContext<'tcx>, from: Ty<'tcx>, to: Ty<'tcx>) -> bool {
13 if let Ok(from) = cx.tcx.try_normalize_erasing_regions(cx.param_env, from)
14 && let Ok(to) = cx.tcx.try_normalize_erasing_regions(cx.param_env, to)
15 && let Ok(from_layout) = cx.tcx.layout_of(cx.param_env.and(from))
16 && let Ok(to_layout) = cx.tcx.layout_of(cx.param_env.and(to))
18 from_layout.size != to_layout.size || from_layout.align.abi != to_layout.align.abi
20 // no idea about layout, so don't lint
25 /// Check if the type conversion can be expressed as a pointer cast, instead of
26 /// a transmute. In certain cases, including some invalid casts from array
27 /// references to pointers, this may cause additional errors to be emitted and/or
28 /// ICE error messages. This function will panic if that occurs.
29 pub(super) fn can_be_expressed_as_pointer_cast<'tcx>(
30 cx: &LateContext<'tcx>,
35 use CastKind::{AddrPtrCast, ArrayPtrCast, FnPtrAddrCast, FnPtrPtrCast, PtrAddrCast, PtrPtrCast};
37 check_cast(cx, e, from_ty, to_ty),
38 Some(PtrPtrCast | PtrAddrCast | AddrPtrCast | ArrayPtrCast | FnPtrPtrCast | FnPtrAddrCast)
42 /// If a cast from `from_ty` to `to_ty` is valid, returns an Ok containing the kind of
43 /// the cast. In certain cases, including some invalid casts from array references
44 /// to pointers, this may cause additional errors to be emitted and/or ICE error
45 /// messages. This function will panic if that occurs.
46 fn check_cast<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) -> Option<CastKind> {
47 let hir_id = e.hir_id;
48 let local_def_id = hir_id.owner.def_id;
50 Inherited::build(cx.tcx, local_def_id).enter(|inherited| {
51 let fn_ctxt = FnCtxt::new(&inherited, cx.param_env, hir_id);
53 // If we already have errors, we can't be sure we can pointer cast.
55 !fn_ctxt.errors_reported_since_creation(),
56 "Newly created FnCtxt contained errors"
59 if let CastCheckResult::Deferred(check) = cast::check_cast(
60 &fn_ctxt, e, from_ty, to_ty,
61 // We won't show any error to the user, so we don't care what the span is here.
64 let res = check.do_check(&fn_ctxt);
66 // do_check's documentation says that it might return Ok and create
67 // errors in the fcx instead of returning Err in some cases. Those cases
68 // should be filtered out before getting here.
70 !fn_ctxt.errors_reported_since_creation(),
71 "`fn_ctxt` contained errors after cast check!"