diff --git a/include/ada/url_pattern.h b/include/ada/url_pattern.h
index aa891d7f3..079c917a2 100644
--- a/include/ada/url_pattern.h
+++ b/include/ada/url_pattern.h
@@ -211,7 +211,7 @@ class url_pattern_component {
   // @see https://urlpattern.spec.whatwg.org/#compile-a-component
   template <url_pattern_encoding_callback F>
   static tl::expected<url_pattern_component, url_pattern_errors> compile(
-      std::string_view input, F encoding_callback,
+      std::string_view input, F& encoding_callback,
       url_pattern_compile_component_options& options);
 
   // @see https://urlpattern.spec.whatwg.org/#create-a-component-match-result
diff --git a/include/ada/url_pattern_helpers-inl.h b/include/ada/url_pattern_helpers-inl.h
index 63d161a08..61126abe9 100644
--- a/include/ada/url_pattern_helpers-inl.h
+++ b/include/ada/url_pattern_helpers-inl.h
@@ -654,7 +654,7 @@ template <url_pattern_encoding_callback F>
 tl::expected<std::vector<url_pattern_part>, url_pattern_errors>
 parse_pattern_string(std::string_view input,
                      url_pattern_compile_component_options& options,
-                     F&& encoding_callback) {
+                     F& encoding_callback) {
   ada_log("parse_pattern_string input=", input);
   // Let parser be a new pattern parser whose encoding callback is encoding
   // callback and segment wildcard regexp is the result of running generate a
@@ -706,7 +706,7 @@ parse_pattern_string(std::string_view input,
       // Run add a part given parser, prefix, name token, regexp or wildcard
       // token, the empty string, and modifier token.
       if (auto error =
-              parser.add_part(prefix, name_token, regexp_or_wildcard_token, {},
+              parser.add_part(prefix, name_token, regexp_or_wildcard_token, "",
                               modifier_token)) {
         ada_log("parser.add_part failed");
         return tl::unexpected(*error);
diff --git a/include/ada/url_pattern_helpers.h b/include/ada/url_pattern_helpers.h
index a2f685992..4c4bdb29c 100644
--- a/include/ada/url_pattern_helpers.h
+++ b/include/ada/url_pattern_helpers.h
@@ -54,7 +54,7 @@ struct Token {
 template <url_pattern_encoding_callback F>
 class url_pattern_parser {
  public:
-  url_pattern_parser(F&& encoding_callback_,
+  url_pattern_parser(F& encoding_callback_,
                      std::string_view segment_wildcard_regexp_)
       : encoding_callback(encoding_callback_),
         segment_wildcard_regexp(std::string(segment_wildcard_regexp_)) {}
@@ -84,7 +84,7 @@ class url_pattern_parser {
   bool is_duplicate_name(std::string_view name);
 
   std::vector<Token> tokens{};
-  F encoding_callback;
+  F& encoding_callback;
   std::string segment_wildcard_regexp;
   std::vector<url_pattern_part> parts{};
   std::string pending_fixed_value{};
@@ -310,7 +310,7 @@ template <url_pattern_encoding_callback F>
 tl::expected<std::vector<url_pattern_part>, url_pattern_errors>
 parse_pattern_string(std::string_view input,
                      url_pattern_compile_component_options& options,
-                     F&& encoding_callback);
+                     F& encoding_callback);
 
 // @see https://urlpattern.spec.whatwg.org/#generate-a-pattern-string
 std::string generate_pattern_string(
diff --git a/src/url_pattern.cpp b/src/url_pattern.cpp
index 68de19967..a468cf32c 100644
--- a/src/url_pattern.cpp
+++ b/src/url_pattern.cpp
@@ -481,7 +481,7 @@ std::string url_pattern_init::to_string() const {
 
 template <url_pattern_encoding_callback F>
 tl::expected<url_pattern_component, url_pattern_errors>
-url_pattern_component::compile(std::string_view input, F encoding_callback,
+url_pattern_component::compile(std::string_view input, F& encoding_callback,
                                url_pattern_compile_component_options& options) {
   ada_log("url_pattern_component::compile input: ", input);
   // Let part list be the result of running parse a pattern string given input,