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#![allow(unused_macros)]
// The following code is copyright 2016 Alex Burka. Available under the MIT OR Apache-2.0 license.
// Some adaptations have been made to the original code.
pub(crate) enum LetElseBodyMustDiverge {}
#[allow(clippy::missing_docs_in_private_items)]
macro_rules! __guard_output {
((($($imms:ident)*) ($($muts:ident)*)),
[($($pattern:tt)*) ($rhs:expr) ($diverge:expr)]) => {
__guard_impl!(@as_stmt
let ($($imms,)* $(mut $muts,)*) = {
#[allow(unused_mut)]
match $rhs {
$($pattern)* => {
($($imms,)* $($muts,)*)
},
_ => {
let _: $crate::shim::LetElseBodyMustDiverge = $diverge;
},
}
}
)
};
}
macro_rules! __guard_impl {
(@as_stmt $s:stmt) => { $s };
(@collect () -> $($rest:tt)*) => {
__guard_output!($($rest)*)
};
(@collect (($($inside:tt)*) $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru)
};
(@collect ({$($inside:tt)*} $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru)
};
(@collect ([$($inside:tt)*] $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru)
};
(@collect (, $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect (.. $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect (@ $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect (_ $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect (& $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect (:: <$($generic:tt),*> $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect (:: $pathend:ident $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect (| $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect () -> $idents, $thru)
};
(@collect ($id:ident: $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect ($pathcomp:ident :: $pathend:ident $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> $idents, $thru)
};
(@collect ($id:ident ($($inside:tt)*) $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru)
};
(@collect ($id:ident {$($inside:tt)*} $($tail:tt)*) -> $idents:tt, $thru:tt) => {
__guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru)
};
(@collect (ref mut $id:ident $($tail:tt)*) -> (($($imms:ident)*) $muts:tt), $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> (($($imms)* $id) $muts), $thru)
};
(@collect (ref $id:ident $($tail:tt)*) -> (($($imms:ident)*) $muts:tt), $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> (($($imms)* $id) $muts), $thru)
};
(@collect (mut $id:ident $($tail:tt)*) -> ($imms:tt ($($muts:ident)*)), $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> ($imms ($($muts)* $id)), $thru)
};
(@collect ($id:ident $($tail:tt)*) -> (($($imms:ident)*) $muts:tt), $thru:tt) => {
__guard_impl!(@collect ($($tail)*) -> (($($imms)* $id) $muts), $thru)
};
(@split (else { $($diverge:tt)* } = $($tail:tt)*) -> ($pat:tt)) => {
__guard_impl!(@collect $pat -> (() ()), [$pat ($($tail)*) ({ $($diverge)* })])
};
(@split (= $($tail:tt)*) -> ($pat:tt)) => {
__guard_impl!(@split expr ($($tail)*) -> ($pat ()))
};
(@split ($head:tt $($tail:tt)*) -> (($($pat:tt)*))) => {
__guard_impl!(@split ($($tail)*) -> (($($pat)* $head)))
};
(@split expr (else { $($tail:tt)* }) -> ($pat:tt $expr:tt)) => {
__guard_impl!(@collect $pat -> (() ()), [$pat $expr ({ $($tail)* })])
};
(@split expr (else { $($body:tt)* } $($tail:tt)*) -> ($pat:tt ($($expr:tt)*))) => {
__guard_impl!(@split expr ($($tail)*) -> ($pat ($($expr)* else { $($body)* })))
};
(@split expr ($head:tt $($tail:tt)*) -> ($pat:tt ($($expr:tt)*))) => {
__guard_impl!(@split expr ($($tail)*) -> ($pat ($($expr)* $head)))
};
(let $($tail:tt)*) => {
__guard_impl!(@split ($($tail)*) -> (()))
};
}
macro_rules! guard {
($($input:tt)*) => {
__guard_impl!($($input)*)
};
}
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