src/tools/clippy/clippy_lints/src/transmute/unsound_collection_transmute.rs

   1 use super::utils::is_layout_incompatible;
   2 use super::UNSOUND_COLLECTION_TRANSMUTE;
   3 use clippy_utils::diagnostics::span_lint;
   4 use rustc_hir::Expr;
   5 use rustc_lint::LateContext;
   6 use rustc_middle::ty::{self, Ty};
   7 use rustc_span::symbol::sym;
   8
   9 /// Checks for `unsound_collection_transmute` lint.
  10 /// Returns `true` if it's triggered, otherwise returns `false`.
  11 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) -> bool {
  12     match (&from_ty.kind(), &to_ty.kind()) {
  13         (ty::Adt(from_adt, from_substs), ty::Adt(to_adt, to_substs)) => {
  14             if from_adt.did() != to_adt.did() {
  15                 return false;
  16             }
  17             if !matches!(
  18                 cx.tcx.get_diagnostic_name(to_adt.did()),
  19                 Some(
  20                     sym::BTreeMap
  21                         | sym::BTreeSet
  22                         | sym::BinaryHeap
  23                         | sym::HashMap
  24                         | sym::HashSet
  25                         | sym::Vec
  26                         | sym::VecDeque
  27                 )
  28             ) {
  29                 return false;
  30             }
  31             if from_substs
  32                 .types()
  33                 .zip(to_substs.types())
  34                 .any(|(from_ty, to_ty)| is_layout_incompatible(cx, from_ty, to_ty))
  35             {
  36                 span_lint(
  37                     cx,
  38                     UNSOUND_COLLECTION_TRANSMUTE,
  39                     e.span,
  40                     &format!("transmute from `{from_ty}` to `{to_ty}` with mismatched layout is unsound"),
  41                 );
  42                 true
  43             } else {
  44                 false
  45             }
  46         },
  47         _ => false,
  48     }
  49 }