error[E0308]: intrinsic has wrong type --> $DIR/E0308.rs:6:20 | LL | fn size_of(); | ^ expected `usize`, found `()` | = note: expected signature `extern "rust-intrinsic" fn() -> usize` found signature `extern "rust-intrinsic" fn()` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0308`.