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macro_rules! overly_complicated {
($fnname:ident, $arg:ident, $ty:ty, $body:block, $val:expr, $pat:pat, $res:path) =>
({
fn $fnname($arg: $ty) -> Option<$ty> $body
match $fnname($val) {
Some($pat) => {
$res
}
_ => { panic!(); }
}
})
}
macro_rules! qpath {
(path, <$type:ty as $trait:path>::$name:ident) => {
<$type as $trait>::$name
};
(ty, <$type:ty as $trait:ty>::$name:ident) => {
<$type as $trait>::$name
//~^ ERROR expected identifier, found `!`
};
}
pub fn main() {
let _: qpath!(path, <str as ToOwned>::Owned);
let _: qpath!(ty, <str as ToOwned>::Owned);
let _: qpath!(ty, <str as !>::Owned);
assert!(overly_complicated!(f, x, Option<usize>, { return Some(x); },
Some(8), Some(y), y) == 8)
}
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