diff --git a/upb_generator/protoc-gen-upb_minitable.cc b/upb_generator/protoc-gen-upb_minitable.cc
index 3c6cd86..e3064ad 100644
--- a/upb_generator/protoc-gen-upb_minitable.cc
+++ b/upb_generator/protoc-gen-upb_minitable.cc
@@ -670,8 +670,9 @@
 }
 
 bool ParseOptions(Plugin* plugin) {
-  for (const auto& pair : ParseGeneratorParameter(plugin->parameter())) {
-    plugin->SetError(absl::Substitute("Unknown parameter: $0", pair.first));
+  const auto param = ParseGeneratorParameter(plugin->parameter());
+  if (!param.empty()) {
+    plugin->SetError(absl::Substitute("Unknown parameter: $0", param[0].first));
     return false;
   }