diff --git a/src/librustc_mir/borrow_check/nll/renumber.rs b/src/librustc_mir/borrow_check/nll/renumber.rs
index c54acda8a62..5267941c8a8 100644
--- a/src/librustc_mir/borrow_check/nll/renumber.rs
+++ b/src/librustc_mir/borrow_check/nll/renumber.rs
@@ -10,7 +10,7 @@
 
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, ClosureSubsts, GeneratorInterior, Ty, TypeFoldable};
-use rustc::mir::{BasicBlock, Location, Mir, Statement, StatementKind};
+use rustc::mir::{BasicBlock, Local, Location, Mir, Statement, StatementKind};
 use rustc::mir::visit::{MutVisitor, TyContext};
 use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
 
@@ -118,6 +118,11 @@ impl<'a, 'gcx, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'gcx, 'tcx> {
         debug!("visit_closure_substs: substs={:?}", substs);
     }
 
+    fn visit_user_assert_ty(&mut self, _ty: &mut Ty<'tcx>, _local: &mut Local,
+                            _location: Location) {
+        debug!("visit_user_assert_ty: skipping renumber");
+    }
+
     fn visit_statement(
         &mut self,
         block: BasicBlock,