error[E0057]: this function takes 2 arguments but 1 argument was supplied --> $DIR/issue-98897.rs:2:5 | LL | (|_, ()| ())([return, ()]); | ^^^^^^^^^^^^-------------- argument #2 of type `()` is missing | note: closure defined here --> $DIR/issue-98897.rs:2:6 | LL | (|_, ()| ())([return, ()]); | ^^^^^^^ help: provide the argument | LL | (|_, ()| ())([return, ()], ()); | ~~~~~~~~~~~~~~~~~~ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0057`.