Support **nil syntax for specifying a method does not accept keyword arguments

This syntax means the method should be treated as a method that
uses keyword arguments, but no specific keyword arguments are
supported, and therefore calling the method with keyword arguments
will raise an ArgumentError.  It is still allowed to double splat
an empty hash when calling the method, as that does not pass
any keyword arguments.

1 files changed, 4 insertions, 0 deletions

diff --git a/vm_args.c b/vm_args.c
index 4e404870da..4eccb62da6 100644
--- a/vm_args.c
+++ b/vm_args.c
@@ -702,6 +702,10 @@ setup_parameters_complex(rb_execution_context_t * const ec, const rb_iseq_t * co
 	args->rest = Qfalse;
     }
 
+    if (kw_flag && iseq->body->param.flags.accepts_no_kwarg) {
+	rb_raise(rb_eArgError, "no keywords accepted");
+    }
+
     switch (arg_setup_type) {
       case arg_setup_method:
 	break; /* do nothing special */