diff --git a/include/internal/catch_test_case_registry_impl.hpp b/include/internal/catch_test_case_registry_impl.hpp
index 27b64eb8..956b3dbf 100644
--- a/include/internal/catch_test_case_registry_impl.hpp
+++ b/include/internal/catch_test_case_registry_impl.hpp
@@ -20,7 +20,7 @@
 namespace Catch {
 
     class TestCase;
-    class IConfig;
+    struct IConfig;
 
     struct RandomNumberGenerator {
         using result_type = std::ptrdiff_t;