diff --git a/src/lib/fcitx/candidatelist.cpp b/src/lib/fcitx/candidatelist.cpp
index ca82b6b6..c2daa8f9 100644
--- a/src/lib/fcitx/candidatelist.cpp
+++ b/src/lib/fcitx/candidatelist.cpp
@@ -125,7 +125,7 @@ Text CandidateWord::textWithComment(std::string separator) const {
     FCITX_D();
     auto text = d->text_;
     if (!d->comment_.empty()) {
-        text.append(separator);
+        text.append(std::move(separator));
         text.append(d->comment_);
     }
     return text;