diff --git vm_args.c vm_args.c
index e4ade6b..cd52227 100644
--- vm_args.c
+++ vm_args.c
@@ -562,10 +562,14 @@ setup_parameters_complex(rb_thread_t * const th, const rb_iseq_t * const iseq, r
 	break;
       case arg_setup_lambda:
 	if (given_argc == 1 &&
-	    given_argc != iseq->param.lead_num &&
+	    given_argc != min_argc &&
+	    (min_argc > 0 || iseq->param.flags.has_block) &&
 	    !iseq->param.flags.has_rest &&
 	    args_check_block_arg0(args, th, msl)) {
-	    given_argc = RARRAY_LENINT(args->rest);
+	    int len = RARRAY_LENINT(args->rest);
+	    if (len >= min_argc && len <= max_argc) {
+	      given_argc = len;
+	    }
 	}
     }