error[E0605]: non-primitive cast: `&&[i32; 1]` as `&[_]` --> $DIR/issue-73886.rs:2:13 | LL | let _ = &&[0] as &[_]; | ^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object error[E0605]: non-primitive cast: `u32` as `Option<_>` --> $DIR/issue-73886.rs:4:13 | LL | let _ = 7u32 as Option<_>; | ^^^^^^^^^^^^^^^^^ help: consider using the `From` trait instead: `Option<_>::from(7u32)` | = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0605`.