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#![cfg_attr(not(feature = "std"), no_std)]
#![allow(dead_code)] // some code is tested for type checking only
use derive_more::TryFrom;
/// Making sure that `TryFrom` does not trigger an ambiguous associated item error for `Error`.
#[derive(TryFrom)]
#[try_from(repr)]
#[repr(u8)]
enum EnumWithError {
Error,
}
#[test]
fn test_with_repr() {
#[derive(TryFrom, Clone, Copy, Debug, Eq, PartialEq)]
#[repr(i16)]
#[try_from(repr)]
enum Enum {
A,
B = -21,
C,
D,
}
assert_eq!(Enum::A, Enum::try_from(0i16).unwrap());
assert_eq!(Enum::B, Enum::try_from(-21).unwrap());
assert_eq!(Enum::C, Enum::try_from(-20).unwrap());
assert_eq!(Enum::D, Enum::try_from(-19).unwrap());
assert!(Enum::try_from(-1).is_err());
}
#[test]
fn enum_without_repr() {
#[derive(TryFrom, Clone, Copy, Debug, Eq, PartialEq)]
#[try_from(repr)]
enum Enum {
A,
B = -21,
C,
D,
}
assert_eq!(Enum::A, Enum::try_from(0isize).unwrap());
assert_eq!(Enum::B, Enum::try_from(-21).unwrap());
assert_eq!(Enum::C, Enum::try_from(-20).unwrap());
assert_eq!(Enum::D, Enum::try_from(-19).unwrap());
assert!(Enum::try_from(-1).is_err());
}
#[test]
fn enum_with_complex_repr() {
#[derive(TryFrom, Clone, Copy, Debug, Eq, PartialEq)]
#[try_from(repr)]
#[repr(align(16), i32)]
enum Enum {
A,
B = -21,
C,
D,
}
assert_eq!(Enum::A, Enum::try_from(0i32).unwrap());
assert_eq!(Enum::B, Enum::try_from(-21).unwrap());
assert_eq!(Enum::C, Enum::try_from(-20).unwrap());
assert_eq!(Enum::D, Enum::try_from(-19).unwrap());
assert!(Enum::try_from(-1).is_err());
}
#[test]
fn test_discriminants_on_enum_with_fields() {
#[derive(TryFrom, Clone, Copy, Debug, Eq, PartialEq)]
#[try_from(repr)]
#[repr(i16)]
enum Enum {
A,
Discriminant = 5,
Field(usize),
Empty {},
FieldWithDiscriminant(u8, i64) = -14,
EmptyTuple(),
}
assert_eq!(Enum::A, Enum::try_from(0).unwrap());
assert_eq!(Enum::Discriminant, Enum::try_from(5).unwrap());
assert!(Enum::try_from(6).is_err());
assert_eq!(Enum::Empty {}, Enum::try_from(7).unwrap());
assert!(Enum::try_from(-14).is_err());
assert_eq!(Enum::EmptyTuple(), Enum::try_from(-13).unwrap());
}
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