diff --git a/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h b/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h
index 8dbb4e857..eb5e5e279 100644
--- a/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h
+++ b/compiler/extensions/cpp/runtime/src/zserio/TypeInfo.h
@@ -1440,7 +1440,7 @@ const IBasicTypeInfo<ALLOC>& FixedSizeBuiltinTypeInfo<ALLOC>::getFixedSignedBitF
                     {"int:63"_sv, SchemaType::FIXED_SIGNED_BITFIELD, CppType::INT64, 63},
                     {"int:64"_sv, SchemaType::FIXED_SIGNED_BITFIELD, CppType::INT64, 64}}};
 
-    return bitFieldTypeInfoArray[static_cast<size_t>(bitSize - 1)];
+    return bitFieldTypeInfoArray[bitSize - 1U];
 }
 
 template <typename ALLOC>