error[E0605]: non-primitive cast: `fn(isize) {foo}` as `extern "C" fn() -> isize` --> $DIR/cast-to-bare-fn.rs:5:13 | LL | let x = foo as extern "C" fn() -> isize; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast error[E0605]: non-primitive cast: `u64` as `fn(isize) -> (isize, isize)` --> $DIR/cast-to-bare-fn.rs:7:13 | LL | let y = v as extern "Rust" fn(isize) -> (isize, isize); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0605`.