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// run-pass
#![feature(type_alias_enum_variants)]
#![allow(irrefutable_let_patterns)]
#[allow(dead_code)]
enum Enum<T> { TSVariant(T), SVariant { v: T } }
type Alias<T> = Enum<T>;
type AliasFixed = Enum<()>;
macro_rules! is_variant {
(TSVariant, $expr:expr) => (is_variant!(@check TSVariant, (_), $expr));
(SVariant, $expr:expr) => (is_variant!(@check SVariant, { v: _ }, $expr));
(@check $variant:ident, $matcher:tt, $expr:expr) => (
assert!(if let Enum::$variant::<()> $matcher = $expr { true } else { false },
"expr does not have correct type");
);
}
fn main() {
// Tuple struct variant
is_variant!(TSVariant, Enum::TSVariant(()));
is_variant!(TSVariant, Enum::TSVariant::<()>(()));
is_variant!(TSVariant, Enum::<()>::TSVariant(()));
is_variant!(TSVariant, Alias::TSVariant(()));
is_variant!(TSVariant, Alias::<()>::TSVariant(()));
is_variant!(TSVariant, AliasFixed::TSVariant(()));
// Struct variant
is_variant!(SVariant, Enum::SVariant { v: () });
is_variant!(SVariant, Enum::SVariant::<()> { v: () });
is_variant!(SVariant, Enum::<()>::SVariant { v: () });
is_variant!(SVariant, Alias::SVariant { v: () });
is_variant!(SVariant, Alias::<()>::SVariant { v: () });
is_variant!(SVariant, AliasFixed::SVariant { v: () });
}
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