1 files changed, 22 insertions, 0 deletions
diff --git a/compiler/rustc_mir_dataflow/src/un_derefer.rs b/compiler/rustc_mir_dataflow/src/un_derefer.rs
new file mode 100644
index 000000000..7e6e25cc6
--- /dev/null
+++ b/compiler/rustc_mir_dataflow/src/un_derefer.rs
@@ -0,0 +1,22 @@
+use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::mir::*;
+use rustc_middle::ty::TyCtxt;
+
+/// Used for reverting changes made by `DerefSeparator`
+pub struct UnDerefer<'tcx> {
+    pub tcx: TyCtxt<'tcx>,
+    pub derefer_sidetable: FxHashMap<Local, Place<'tcx>>,
+}
+
+impl<'tcx> UnDerefer<'tcx> {
+    #[inline]
+    pub fn derefer(&self, place: PlaceRef<'tcx>, body: &Body<'tcx>) -> Option<Place<'tcx>> {
+        let reffed = self.derefer_sidetable.get(&place.local)?;
+
+        let new_place = reffed.project_deeper(place.projection, self.tcx);
+        if body.local_decls[new_place.local].is_deref_temp() {
+            return self.derefer(new_place.as_ref(), body);
+        }
+        Some(new_place)
+    }
+}