diff --git a/src/evaluator/evaluator.cc b/src/evaluator/evaluator.cc
index 62f6bef8..8c1029f8 100644
--- a/src/evaluator/evaluator.cc
+++ b/src/evaluator/evaluator.cc
@@ -94,7 +94,7 @@ auto Evaluator::validate(const Template &schema,
 const sourcemeta::jsontoolkit::JSON Evaluator::null{nullptr};
 const sourcemeta::jsontoolkit::JSON Evaluator::empty_string{""};
 
-auto Evaluator::hash(const std::size_t &resource,
+auto Evaluator::hash(const std::size_t resource,
                      const sourcemeta::jsontoolkit::JSON::String &fragment)
     const noexcept -> std::size_t {
   return resource + this->hasher_(fragment);
diff --git a/src/evaluator/include/sourcemeta/blaze/evaluator.h b/src/evaluator/include/sourcemeta/blaze/evaluator.h
index 8be4032f..45025589 100644
--- a/src/evaluator/include/sourcemeta/blaze/evaluator.h
+++ b/src/evaluator/include/sourcemeta/blaze/evaluator.h
@@ -154,7 +154,7 @@ class SOURCEMETA_BLAZE_EVALUATOR_EXPORT Evaluator {
   static const sourcemeta::jsontoolkit::JSON empty_string;
 
   auto
-  hash(const std::size_t &resource,
+  hash(const std::size_t resource,
        const sourcemeta::jsontoolkit::JSON::String &fragment) const noexcept
       -> std::size_t;