error[E0057]: this function takes 2 arguments but 1 argument was supplied --> $DIR/issue-99482.rs:3:14 | LL | let _f = f(main); | ^ ---- an argument of type `()` is missing | note: closure defined here --> $DIR/issue-99482.rs:2:13 | LL | let f = |_: (), f: fn()| f; | ^^^^^^^^^^^^^^^^ help: provide the argument | LL | let _f = f((), main); | ~~~~~~~~~~ error: aborting due to previous error For more information about this error, try `rustc --explain E0057`.