fix const_eval for opts

src/interp.rs

@@ -949,6 +949,7 @@ pub fn const_eval(
                 ConstVal::None
             })
         }
+        (_, args) if args.iter().any(|&arg| arg == ConstVal::None) => None,
         (op, args) => unimplemented!(
             "Undefined operator or arg combination: {:?}, {:?}",
             op,