core/pat.rs
//! Helper module for exporting the `pattern_type` macro
/// Creates a pattern type.
/// ```ignore (cannot test this from within core yet)
/// type Positive = std::pat::pattern_type!(i32 is 1..);
/// ```
#[macro_export]
#[rustc_builtin_macro(pattern_type)]
#[unstable(feature = "core_pattern_type", issue = "123646")]
macro_rules! pattern_type {
($($arg:tt)*) => {
/* compiler built-in */
};
}