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 clippy_utils::match_any_diagnostic_items;
   5 use rustc_hir::Expr;
   6 use rustc_lint::LateContext;
   7 use rustc_middle::ty::{self, Ty};
   8 use rustc_span::symbol::{sym, Symbol};
   9
  10 // used to check for UNSOUND_COLLECTION_TRANSMUTE
  11 static COLLECTIONS: &[Symbol] = &[
  12     sym::Vec,
  13     sym::VecDeque,
  14     sym::BinaryHeap,
  15     sym::BTreeSet,
  16     sym::BTreeMap,
  17     sym::HashSet,
  18     sym::HashMap,
  19 ];
  20
  21 /// Checks for `unsound_collection_transmute` lint.
  22 /// Returns `true` if it's triggered, otherwise returns `false`.
  23 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) -> bool {
  24     match (&from_ty.kind(), &to_ty.kind()) {
  25         (ty::Adt(from_adt, from_substs), ty::Adt(to_adt, to_substs)) => {
  26             if from_adt.did != to_adt.did || match_any_diagnostic_items(cx, to_adt.did, COLLECTIONS).is_none() {
  27                 return false;
  28             }
  29             if from_substs
  30                 .types()
  31                 .zip(to_substs.types())
  32                 .any(|(from_ty, to_ty)| is_layout_incompatible(cx, from_ty, to_ty))
  33             {
  34                 span_lint(
  35                     cx,
  36                     UNSOUND_COLLECTION_TRANSMUTE,
  37                     e.span,
  38                     &format!(
  39                         "transmute from `{}` to `{}` with mismatched layout is unsound",
  40                         from_ty, to_ty
  41                     ),
  42                 );
  43                 true
  44             } else {
  45                 false
  46             }
  47         },
  48         _ => false,
  49     }
  50 }