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/// Constructs a [`TypeNe`](crate::TypeNe)
/// of types that are statically known to be different.
///
/// This macro is syntactic sugar for calling
/// [`TypeNe::with_fn`](crate::TypeNe::with_fn) with a private
/// [`InjTypeFn`](crate::InjTypeFn) implementor.
///
/// # Syntax
///
/// This macro takes this syntax:
///
/// ```text
/// $( < $($generic_param:generic_param),* $(,)? > )? $left_type:ty, $right_type:ty
/// $(where $($where_cause:tt)*)?
/// ```
///
/// # Limitations
///
/// This macro can't use generic parameters from the surrounding scope,
/// they must be redeclared within the macro to be used.
///
/// # Example
///
/// ```rust
/// use typewit::TypeNe;
///
/// const _: TypeNe<u8, (u8,)> = foo();
///
/// const fn foo<T>() -> TypeNe<T, (T,)>
/// where
/// (T,): Copy,
/// {
/// typewit::type_ne!{
/// <X> X, (X,)
/// where (X,): Copy
/// }
/// }
///
///
/// ```
#[macro_export]
macro_rules! type_ne {
(< $($generics:tt)* ) => {
$crate::__::__parse_in_generics! {
($crate::__tyne_parsed_capture_generics !())
[] [] [$($generics)*]
}
};
($left_ty:ty, $($rem:tt)*) => {
$crate::__tyne_parsed_capture_generics! {
[]
[]
[]
$left_ty, $($rem)*
}
};
($($rem:tt)*) => {
$crate::__::compile_error!{"invalid arguments for `type_ne` macro"}
}
}
#[doc(hidden)]
#[macro_export]
macro_rules! __tyne_parsed_capture_generics {
(
[$(($gen_arg:tt ($($($gen_phantom:tt)+)?) $($gen_rem:tt)*))*]
[$(($($gen_params:tt)*))*]
$deleted_markers:tt
$left_ty:ty, $right_ty:ty $(,)?
$(where $($where:tt)*)?
) => ({
struct __TypeNeParameterizer<$($($gen_params)*,)*>(
$crate::__::PhantomData<(
$($($crate::__::PhantomData<$($gen_phantom)+>,)?)*
)>
)$( where $($where)* )?;
impl<$($($gen_params)*,)*> __TypeNeParameterizer<$($gen_arg,)*>
$( where $($where)* )?
{
const NEW: Self = Self($crate::__::PhantomData);
}
$crate::__impl_with_span! {
$left_ty // span
() // impl attrs
( <$($($gen_params)*,)*> $crate::TypeFn<$crate::type_ne::LeftArg> )
// for
(__TypeNeParameterizer<$($gen_arg,)*>)
( $( where $($where)* )? )
(
type Output = $left_ty;
const TYPE_FN_ASSERTS: () = {
let _: $crate::CallInjFn<Self, $crate::type_ne::LeftArg>;
};
)
}
$crate::__impl_with_span! {
$left_ty // span
() // impl attrs
( <$($($gen_params)*,)*> $crate::RevTypeFn<$left_ty> )
// for
(__TypeNeParameterizer<$($gen_arg,)*>)
( $( where $($where)* )? )
(
type Arg = $crate::type_ne::LeftArg;
)
}
$crate::__impl_with_span! {
$right_ty // span
() // impl attrs
( <$($($gen_params)*,)*> $crate::TypeFn<$crate::type_ne::RightArg> )
// for
(__TypeNeParameterizer<$($gen_arg,)*>)
( $( where $($where)* )? )
(
type Output = $right_ty;
const TYPE_FN_ASSERTS: () = {
let _: $crate::CallInjFn<Self, $crate::type_ne::RightArg>;
};
)
}
$crate::__impl_with_span! {
$right_ty // span
() // impl attrs
( <$($($gen_params)*,)*> $crate::RevTypeFn<$right_ty> )
// for
(__TypeNeParameterizer<$($gen_arg,)*>)
( $( where $($where)* )? )
(
type Arg = $crate::type_ne::RightArg;
)
}
$crate::TypeNe::with_fn(
__TypeNeParameterizer::NEW
)
});
}