Fix Double Copy implementation vulnerability

Author: VulnBandit

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -267,6 +267,11 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                 kind,
                 self.is_upvar_field_projection(original_path.as_ref())
             );
+            if self.maybe_copy(original_path.ty(self.body, self.infcx.tcx).ty) {
+                // If the type may implement Copy, skip the error.
+                // It's an error with the Copy implementation (e.g. duplicate Copy) rather than borrow check
+                return;
+            }
             (
                 match kind {
                     &IllegalMoveOriginKind::BorrowedContent { target_place } => self
@@ -291,6 +296,12 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         self.buffer_error(err);
     }
 
+    fn maybe_copy(&mut self, ty: Ty<'tcx>) -> bool {
+        use rustc_trait_selection::infer::InferCtxtExt;
+        let Some(copy_trait_def) = self.infcx.tcx.lang_items().copy_trait() else { return false };
+        self.infcx.type_implements_trait(copy_trait_def, [ty], self.param_env).may_apply()
+    }
+
     fn report_cannot_move_from_static(&mut self, place: Place<'tcx>, span: Span) -> Diag<'infcx> {
         let description = if place.projection.len() == 1 {
             format!("static item {}", self.describe_any_place(place.as_ref()))