error[E0618]: expected function, found `Foo` --> $DIR/issue-46771.rs:3:23 | LL | struct Foo; | ---------- `Foo` defined here LL | (1 .. 2).find(|_| Foo(0) == 0); | ^^^--- | | | call expression requires function error: aborting due to previous error For more information about this error, try `rustc --explain E0618`.