diff --git a/src/string.hh b/src/string.hh
index 4604cd6f..50926787 100644
--- a/src/string.hh
+++ b/src/string.hh
@@ -25,8 +25,7 @@ public:
    explicit String(Codepoint cp, CharCount count = 1)
    {
        std::string str;
-       auto it = back_inserter(str);
-       utf8::dump(it, cp);
+       utf8::dump(back_inserter(str), cp);
        for (CharCount i = 0; i < count; ++i)
            m_content += str;
    }
@@ -113,8 +112,7 @@ inline String operator"" _str(const char* str, size_t)
 inline String codepoint_to_str(Codepoint cp)
 {
     std::string str;
-    auto it = back_inserter(str);
-    utf8::dump(it, cp);
+    utf8::dump(back_inserter(str), cp);
     return String(str);
 }
 
diff --git a/src/utf8.hh b/src/utf8.hh
index 7b247092..ebbb430f 100644
--- a/src/utf8.hh
+++ b/src/utf8.hh
@@ -140,7 +140,7 @@ Codepoint codepoint(Iterator it)
 struct invalid_codepoint{};
 
 template<typename OutputIterator>
-void dump(OutputIterator& it, Codepoint cp)
+void dump(OutputIterator&& it, Codepoint cp)
 {
     if (cp <= 0x7F)
         *it++ = cp;