diff --git a/quickjs.c b/quickjs.c
index f8b37e497..c1b7db7a2 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -32777,8 +32777,10 @@ static JSValue js_create_function(JSContext *ctx, JSFunctionDef *fd)
             }
         } else {
             b->vardefs = (void *)((uint8_t*)b + vardefs_offset);
-            memcpy(b->vardefs, fd->args, fd->arg_count * sizeof(fd->args[0]));
-            memcpy(b->vardefs + fd->arg_count, fd->vars, fd->var_count * sizeof(fd->vars[0]));
+            if (fd->vars && fd->arg_count > 0) {
+                memcpy(b->vardefs, fd->args, fd->arg_count * sizeof(fd->args[0]));
+                memcpy(b->vardefs + fd->arg_count, fd->vars, fd->var_count * sizeof(fd->vars[0]));
+	    }
         }
         b->var_count = fd->var_count;
         b->arg_count = fd->arg_count;