error: `singleton` option not allowed here
  --> tests/compile-fail/singleton_only_for_input.rs:15:18
   |
15 | #[salsa::tracked(singleton)]
   |                  ^^^^^^^^^

error: `singleton` option not allowed here
  --> tests/compile-fail/singleton_only_for_input.rs:22:22
   |
22 | #[salsa::accumulator(singleton)]
   |                      ^^^^^^^^^