error: Name `f` forms or references an illegal self-referential cycle (1/1).
 --> tests/compile-fail/surface_forwardref_self3.rs:6:9
  |
6 |         f -> for_each(std::mem::drop);
  |         ^

error: `for_each` must have exactly 1 input(s), actually has 0.
 --> tests/compile-fail/surface_forwardref_self3.rs:6:14
  |
6 |         f -> for_each(std::mem::drop);
  |              ^^^^^^^^^^^^^^^^^^^^^^^^