diff --git a/tools/widl/widltypes.h b/tools/widl/widltypes.h
index e6b0369..0851d2b 100644
--- a/tools/widl/widltypes.h
+++ b/tools/widl/widltypes.h
@@ -539,6 +539,7 @@ static inline enum type_type type_get_type_detect_alias(const type_t *type)
     default:
         assert(0);
     }
+    return 0;
 }
 
 #define STATEMENTS_FOR_EACH_FUNC(stmt, stmts) \