diff --git a/src/reader/internal/block_cache.cpp b/src/reader/internal/block_cache.cpp
index 696cf365..8d8199f5 100644
--- a/src/reader/internal/block_cache.cpp
+++ b/src/reader/internal/block_cache.cpp
@@ -147,7 +147,7 @@ class block_request {
   block_request(block_request&&) = default;
   block_request& operator=(block_request&&) = default;
 
-  bool operator<(const block_request& rhs) const { return end_ < rhs.end_; }
+  bool operator<(block_request const& rhs) const { return end_ < rhs.end_; }
 
   size_t end() const { return end_; }