diff --git a/libwccl/ops/match/conditions/isannotatedas.cpp b/libwccl/ops/match/conditions/isannotatedas.cpp
index a968f4057c5c50413e0a08d9612738c28337f97a..a7de36d139c596a7d3f4fae6c9cd90b67ab35891 100644
--- a/libwccl/ops/match/conditions/isannotatedas.cpp
+++ b/libwccl/ops/match/conditions/isannotatedas.cpp
@@ -43,7 +43,7 @@ MatchResult IsAnnotatedAs::apply(const ActionExecContext& context) const
 	return MatchResult(ann_match);
 }
 
-std::string IsAnnotatedAs::to_string(const Corpus2::Tagset& tagset) const
+std::string IsAnnotatedAs::to_string(const Corpus2::Tagset& /*tagset*/) const
 {
 	std::ostringstream os;
 	os << name() << "(\"" << chan_name_ << "\")";