diff --git a/src/help/topic_text_generators.hpp b/src/help/topic_text_generators.hpp
index e4f83c37d282..7ed7c0bbb222 100644
--- a/src/help/topic_text_generators.hpp
+++ b/src/help/topic_text_generators.hpp
@@ -76,6 +76,7 @@ class unit_topic_generator : public topic_text_generator
 		: type_(t)
 		, variation_(variation)
 	{
+		UNUSED(type_);
 	}
 
 	/** Inherited from @ref topic_text_generator. */