diff --git a/include/flatbuffers/flatbuffers.h b/include/flatbuffers/flatbuffers.h
index 799f6478a..279afd545 100644
--- a/include/flatbuffers/flatbuffers.h
+++ b/include/flatbuffers/flatbuffers.h
@@ -592,7 +592,7 @@ static inline const char *GetCstring(const String *str) {
 static inline flatbuffers::string_view GetStringView(const String *str) {
   return str ? str->string_view() : flatbuffers::string_view();
 }
-#endif  // FLATBUFFERS_HAS_STRING_VIEW
+#endif // FLATBUFFERS_HAS_STRING_VIEW
 
 // Allocator interface. This is flatbuffers-specific and meant only for
 // `vector_downward` usage.
diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
index cd81d822d..566482d21 100644
--- a/src/idl_parser.cpp
+++ b/src/idl_parser.cpp
@@ -1559,7 +1559,7 @@ CheckedError Parser::ParseMetaData(SymbolTable<Value> *attributes) {
                      name);
       NEXT();
       auto e = new Value();
-      attributes->Add(name, e);
+      if (attributes->Add(name, e)) Warning("attribute already found: " + name);
       if (Is(':')) {
         NEXT();
         ECHECK(ParseSingleValue(&name, *e, true));