diff --git a/src/libflake/flakeref.cc b/src/libflake/flakeref.cc
index 5b1c3e8b2..a562e29d2 100644
--- a/src/libflake/flakeref.cc
+++ b/src/libflake/flakeref.cc
@@ -82,7 +82,7 @@ std::pair<FlakeRef, std::string> parsePathFlakeRefWithFragment(
     auto succeeds = std::regex_match(url, match, pathFlakeRegex);
     assert(succeeds);
     auto path = match[1].str();
-    auto query = decodeQuery(match[3]);
+    auto query = decodeQuery(match[3].str());
     auto fragment = percentDecode(match[5].str());
 
     if (baseDir) {
diff --git a/src/libutil/url.cc b/src/libutil/url.cc
index cdfba8a83..07f4b29ea 100644
--- a/src/libutil/url.cc
+++ b/src/libutil/url.cc
@@ -179,7 +179,7 @@ try {
         .scheme = scheme,
         .authority = authority,
         .path = path,
-        .query = decodeQuery(std::string(query)),
+        .query = decodeQuery(query),
         .fragment = fragment,
     };
 } catch (boost::system::system_error & e) {
@@ -201,7 +201,7 @@ std::string percentEncode(std::string_view s, std::string_view keep)
         s, [keep](char c) { return boost::urls::unreserved_chars(c) || keep.find(c) != keep.npos; });
 }
 
-StringMap decodeQuery(const std::string & query)
+StringMap decodeQuery(std::string_view query)
 try {
     /* For back-compat unescaped characters are allowed. */
     auto fixedEncodedQuery = percentEncodeCharSet(query, extraAllowedCharsInQuery);