ast.c: AST.of against C method should return nil (as Ruby 2.6--3.0)

1 files changed, 1 insertions, 1 deletions

diff --git a/ast.c b/ast.c
index e1c044e24c..84e5fdcecc 100644
--- a/ast.c
+++ b/ast.c
@@ -214,7 +214,7 @@ ast_s_of(rb_execution_context_t *ec, VALUE module, VALUE body, VALUE keep_script
             iseq = rb_method_iseq(body);
         }
         if (!iseq) {
-            rb_raise(rb_eArgError, "cannot get AST for method that is not defined in Ruby");
+            return Qnil;
         }
         if (rb_iseq_from_eval_p(iseq)) {
             rb_raise(rb_eArgError, "cannot get AST for method defined in eval");