diff --git a/src/nsolid/nsolid_util.h b/src/nsolid/nsolid_util.h
index d4e4fdb3be..460a762aa6 100644
--- a/src/nsolid/nsolid_util.h
+++ b/src/nsolid/nsolid_util.h
@@ -226,7 +226,7 @@ class RingBuffer {
     size_--;
   }
 
-  void push(T& value) {
+  void push(const T& value) {
     buffer_[tail_] = value;
     tail_ = (tail_ + 1) % capacity_;