diff --git a/clang/lib/Analysis/ThreadSafety.cpp b/clang/lib/Analysis/ThreadSafety.cpp
index 9041000b0ff7a..ef7d2cf1ebec2 100644
--- a/clang/lib/Analysis/ThreadSafety.cpp
+++ b/clang/lib/Analysis/ThreadSafety.cpp
@@ -402,7 +402,7 @@ class LocalVariableMap {
     // The map with which Exp should be interpreted.
     Context Ctx;
 
-    bool isReference() { return !Exp; }
+    bool isReference() const { return !Exp; }
 
   private:
     // Create ordinary variable definition