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/// Unpack the tuple or struct from an enum variant.
/// Each extracted variable is decalred as mutable for maximum flexibility.
///
/// ```edition2018
/// # use tari_test_utils::unpack_enum;
///
/// #[derive(Debug)]
/// enum AnyEnum<'a> {
///     Tuple(u8, &'a str),
///     Struct { name: &'a str, age: u8 },
///     SingleVariant,
/// }
///
/// let e = AnyEnum::Tuple(123, "Hubert etc.");
/// unpack_enum!(AnyEnum::Tuple(age, name) = e);
/// assert_eq!(age, 123);
/// assert_eq!(name, "Hubert etc.");
///
/// let e = AnyEnum::Struct {
///     age: 123,
///     name: "Hubert etc.",
/// };
/// unpack_enum!(AnyEnum::Struct { age, name } = e);
/// assert_eq!(age, 123);
/// assert_eq!(name, "Hubert etc.");
///
/// let e = AnyEnum::SingleVariant;
/// unpack_enum!(AnyEnum::SingleVariant = e);
///
/// // Will panic
/// // let e = AnyEnum::Tuple(123, "Hubert etc.");
/// // unpack_enum!(AnyEnum::SingleVariant = e);
/// ```
#[macro_export]
macro_rules! unpack_enum {
    ($($enum_key:ident)::+ { .. } = $enum:expr) => {
        match $enum {
            $($enum_key)::+{..} => (),
            v => panic!("Unexpected enum variant '{:?}' given to unpack_enum", v),
        }
    };
    ($($enum_key:ident)::+ { $($idents:ident),+ ,.. } = $enum:expr) => {
        let ($(mut $idents),+) =  match $enum {
            $($enum_key)::+{$($idents),+, .. } => ($($idents),+),
            v => panic!("Unexpected enum variant '{:?}' given to unpack_enum", v),
        };
    };
    ($($enum_key:ident)::+ { $($idents:ident),+ } = $enum:expr) => {
        let ($(mut $idents),+) =  match $enum {
            $($enum_key)::+{$($idents),+ } => ($($idents),+),
            v => panic!("Unexpected enum variant '{:?}' given to unpack_enum", v),
        };
    };

    ($($enum_key:ident)::+ ( $($idents:ident),* ) = $enum:expr) => {
        let ($(mut $idents),+) =  match $enum {
            $($enum_key)::+($($idents),+) => ($($idents),+),
            v => panic!("Unexpected enum variant '{:?}' given to unpack_enum", v),
        };
    };
    // This matches `MyEnum::First = some_var` and will panic if the enum does not match
    ($($enum_key:ident)::+ = $enum:expr) => {
        match $enum {
            $($enum_key)::+ => {},
            v => panic!("Unexpected enum variant '{:?}' given to unpack_enum", v),
        };
    };
    ($( $pattern:pat_param )|+ = $enum:expr) => {
         match $enum {
            $( $pattern )|+ => {},
            v => panic!("Unexpected enum variant '{:?}' given to unpack_enum", v),
        };
    }
}
