2 files changed, 22 insertions, 12 deletions
diff --git a/src/util/string.h b/src/util/string.h
index b8e2a06235..cdb41630c6 100644
--- a/src/util/string.h
+++ b/src/util/string.h
@@ -30,10 +30,11 @@ NODISCARD inline std::string TrimString(const std::string& str, const std::strin
  * @param separator  The separator
  * @param unary_op   Apply this operator to each item in the list
  */
-template <typename T, typename UnaryOp>
-std::string Join(const std::vector<T>& list, const std::string& separator, UnaryOp unary_op)
+template <typename T, typename BaseType, typename UnaryOp>
+auto Join(const std::vector<T>& list, const BaseType& separator, UnaryOp unary_op)
+    -> decltype(unary_op(list.at(0)))
 {
-    std::string ret;
+    decltype(unary_op(list.at(0))) ret;
     for (size_t i = 0; i < list.size(); ++i) {
         if (i > 0) ret += separator;
         ret += unary_op(list.at(i));
@@ -41,9 +42,16 @@ std::string Join(const std::vector<T>& list, const std::string& separator, Unary
     return ret;
 }
 
+template <typename T>
+T Join(const std::vector<T>& list, const T& separator)
+{
+    return Join(list, separator, [](const T& i) { return i; });
+}
+
+// Explicit overload needed for c_str arguments, which would otherwise cause a substitution failure in the template above.
 inline std::string Join(const std::vector<std::string>& list, const std::string& separator)
 {
-    return Join(list, separator, [](const std::string& i) { return i; });
+    return Join<std::string>(list, separator);
 }
 
 /**
diff --git a/src/util/translation.h b/src/util/translation.h
index 45595405e7..268bcf30a7 100644
--- a/src/util/translation.h
+++ b/src/util/translation.h
@@ -16,21 +16,23 @@
 struct bilingual_str {
     std::string original;
     std::string translated;
+
+    bilingual_str& operator+=(const bilingual_str& rhs)
+    {
+        original += rhs.original;
+        translated += rhs.translated;
+        return *this;
+    }
 };
 
-inline bilingual_str operator+(const bilingual_str& lhs, const bilingual_str& rhs)
+inline bilingual_str operator+(bilingual_str lhs, const bilingual_str& rhs)
 {
-    return bilingual_str{
-        lhs.original + rhs.original,
-        lhs.translated + rhs.translated};
+    lhs += rhs;
+    return lhs;
 }
 
 /** Mark a bilingual_str as untranslated */
 inline bilingual_str Untranslated(std::string original) { return {original, original}; }
-/** Unary operator to return the original */
-inline std::string OpOriginal(const bilingual_str& b) { return b.original; }
-/** Unary operator to return the translation */
-inline std::string OpTranslated(const bilingual_str& b) { return b.translated; }
 
 namespace tinyformat {
 template <typename... Args>