error[E0057]: this function takes 0 arguments but 1 argument was supplied --> $DIR/issue-16939.rs:5:9 | LL | |t| f(t); | ^ - | | | unexpected argument | help: remove the extra argument | note: callable defined here --> $DIR/issue-16939.rs:4:12 | LL | fn _foo (f: F) { | ^^^^ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0057`.