diff --git a/frontends/verilog/verilog_frontend.cc b/frontends/verilog/verilog_frontend.cc
index de05d29a7..61db0a176 100644
--- a/frontends/verilog/verilog_frontend.cc
+++ b/frontends/verilog/verilog_frontend.cc
@@ -465,6 +465,10 @@ struct VerilogFrontend : public Frontend {
 				log("-- Verilog code after preprocessor --\n%s-- END OF DUMP --\n", code_after_preproc.c_str());
 			lexin = new std::istringstream(code_after_preproc);
 		}
+		if (design->verilog_packages.empty()) {
+			// might be because of a `design -reset-vlog` command
+			pkg_user_types.clear();
+		}
 
 		frontend_verilog_yyset_lineno(1);
 		frontend_verilog_yyrestart(NULL);
diff --git a/frontends/verilog/verilog_parser.y b/frontends/verilog/verilog_parser.y
index 690dfdb6e..f7e3afd13 100644
--- a/frontends/verilog/verilog_parser.y
+++ b/frontends/verilog/verilog_parser.y
@@ -522,6 +522,7 @@ interface:
 		ast_stack.pop_back();
 		log_assert(ast_stack.size() == 1);
 		current_ast_mod = NULL;
+		user_types.clear();
 	};
 
 interface_body: