#[allow_internal_unstable(rustc_attrs, liballoc_internals)]

macro_rules! vec {

() => (

$crate::__rust_force_expr!($crate::vec::Vec::new())

$crate::vec::Vec::new()

);

($elem:expr; $n:expr) => (

$crate::__rust_force_expr!($crate::vec::from_elem($elem, $n))

$crate::vec::from_elem($elem, $n)

);

($($x:expr),+ $(,)?) => (

$crate::__rust_force_expr!(<[_]>::into_vec(

<[_]>::into_vec(

// This rustc_box is not required, but it produces a dramatic improvement in compile

// time when constructing arrays with many elements.

#[rustc_box]

$crate::boxed::Box::new([$($x),+])

))

)

);

}

res

}}

}

/// Force AST node to an expression to improve diagnostics in pattern position.

#[doc(hidden)]

#[macro_export]

#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]

macro_rules! __rust_force_expr {

($e:expr) => {

$e

};

}