diff --git a/src/frontends/qt/GuiInputMethod.h b/src/frontends/qt/GuiInputMethod.h
index c8ce0a873b..36b129f63f 100644
--- a/src/frontends/qt/GuiInputMethod.h
+++ b/src/frontends/qt/GuiInputMethod.h
@@ -52,12 +52,6 @@ public:
 			return start_ == another.start_ && length_ == another.length_ &&
 			        char_format_ == another.char_format_;
 		}
-		PreeditSegment & operator=(const PreeditSegment & another) {
-			start_ = another.start_;
-			length_ = another.length_;
-			char_format_ = another.char_format_;
-			return *this;
-		}
 	};
 
 	struct PreeditStyle {