diff -ur orig/rply.c new/rply.c
--- orig/rply.c	2017-02-27 10:57:47.543219868 +0100
+++ new/rply.c	2017-02-27 11:02:06.678492094 +0100
@@ -376,7 +376,7 @@
     if (error_cb == NULL) error_cb = ply_error_cb;
     assert(fp);
     if (!ply_type_check()) {
-        error_cb(ply, "Incompatible type system");
+        error_cb(NULL, "Incompatible type system");
         return NULL;
     }
     ply = ply_alloc();
@@ -478,7 +478,7 @@
     p_ply ply;
     assert(fp && storage_mode <= PLY_DEFAULT);
     if (!ply_type_check()) {
-        error_cb(ply, "Incompatible type system");
+        error_cb(NULL, "Incompatible type system");
         return NULL;
     }
     ply = ply_alloc();