47 lines
1.2 KiB
Rust
47 lines
1.2 KiB
Rust
|
// Tests that `as` casts from enums to numeric types succeed
|
||
|
|
// only if the enum type is "unit-only" or "fieldless" as
|
||
|
|
// described here: https://doc.rust-lang.org/reference/items/enumerations.html#casting
|
||
|
|
|
||
|
|
pub enum UnitOnly {
|
||
|
|
Foo,
|
||
|
|
Bar,
|
||
|
|
Baz,
|
||
|
|
}
|
||
|
|
|
||
|
|
pub enum Fieldless {
|
||
|
|
Tuple(),
|
||
|
|
Struct{},
|
||
|
|
Unit,
|
||
|
|
}
|
||
|
|
|
||
|
|
pub enum NotUnitOnlyOrFieldless {
|
||
|
|
Foo,
|
||
|
|
Bar(u8),
|
||
|
|
Baz
|
||
|
|
}
|
||
|
|
|
||
|
|
fn main() {
|
||
|
|
let unit_only = UnitOnly::Foo;
|
||
|
|
|
||
|
|
let _ = unit_only as isize;
|
||
|
|
let _ = unit_only as i32;
|
||
|
|
let _ = unit_only as usize;
|
||
|
|
let _ = unit_only as u32;
|
||
|
|
|
||
|
|
|
||
|
|
let fieldless = Fieldless::Struct{};
|
||
|
|
|
||
|
|
let _ = fieldless as isize;
|
||
|
|
let _ = fieldless as i32;
|
||
|
|
let _ = fieldless as usize;
|
||
|
|
let _ = fieldless as u32;
|
||
|
|
|
||
|
|
|
||
|
|
let not_unit_only_or_fieldless = NotUnitOnlyOrFieldless::Foo;
|
||
|
|
|
||
|
|
let _ = not_unit_only_or_fieldless as isize; //~ ERROR non-primitive cast: `NotUnitOnlyOrFieldless` as `isize`
|
||
|
|
let _ = not_unit_only_or_fieldless as i32; //~ ERROR non-primitive cast: `NotUnitOnlyOrFieldless` as `i32`
|
||
|
|
let _ = not_unit_only_or_fieldless as usize; //~ ERROR non-primitive cast: `NotUnitOnlyOrFieldless` as `usize`
|
||
|
|
let _ = not_unit_only_or_fieldless as u32; //~ ERROR non-primitive cast: `NotUnitOnlyOrFieldless` as `u32`
|
||
|
|
}
|