mirror of
https://github.com/rust-lang/rust.git
synced 2024-12-11 08:05:12 +00:00
97 lines
3.0 KiB
Rust
97 lines
3.0 KiB
Rust
// Test that slice subslice patterns are correctly handled in const evaluation.
|
|
|
|
//@ run-pass
|
|
|
|
#[derive(PartialEq, Debug, Clone)]
|
|
struct N(u8);
|
|
|
|
#[derive(PartialEq, Debug, Clone)]
|
|
struct Z;
|
|
|
|
macro_rules! n {
|
|
($($e:expr),* $(,)?) => {
|
|
[$(N($e)),*]
|
|
}
|
|
}
|
|
|
|
// This macro has an unused variable so that it can be repeated base on the
|
|
// number of times a repeated variable (`$e` in `z`) occurs.
|
|
macro_rules! zed {
|
|
($e:expr) => { Z }
|
|
}
|
|
|
|
macro_rules! z {
|
|
($($e:expr),* $(,)?) => {
|
|
[$(zed!($e)),*]
|
|
}
|
|
}
|
|
|
|
// Compare constant evaluation and runtime evaluation of a given expression.
|
|
macro_rules! compare_evaluation_inner {
|
|
($e:expr, $t:ty $(,)?) => {{
|
|
const CONST_EVAL: $t = $e;
|
|
const fn const_eval() -> $t { $e }
|
|
static CONST_EVAL2: $t = const_eval();
|
|
let runtime_eval = $e;
|
|
assert_eq!(CONST_EVAL, runtime_eval);
|
|
assert_eq!(CONST_EVAL2, runtime_eval);
|
|
}}
|
|
}
|
|
|
|
// Compare the result of matching `$e` against `$p` using both `if let` and
|
|
// `match`.
|
|
macro_rules! compare_evaluation {
|
|
($p:pat, $e:expr, $matches:expr, $t:ty $(,)?) => {{
|
|
compare_evaluation_inner!(if let $p = $e as &[_] { $matches } else { None }, $t);
|
|
compare_evaluation_inner!(match $e as &[_] { $p => $matches, _ => None }, $t);
|
|
}}
|
|
}
|
|
|
|
// Repeat `$test`, substituting the given macro variables with the given
|
|
// identifiers.
|
|
//
|
|
// For example:
|
|
//
|
|
// repeat! {
|
|
// ($name); X; Y:
|
|
// struct $name;
|
|
// }
|
|
//
|
|
// Expands to:
|
|
//
|
|
// struct X; struct Y;
|
|
//
|
|
// This is used to repeat the tests using both the `N` and `Z`
|
|
// types.
|
|
macro_rules! repeat {
|
|
(($($dollar:tt $placeholder:ident)*); $($($values:ident),+);*: $($test:tt)*) => {
|
|
macro_rules! single {
|
|
($($dollar $placeholder:ident),*) => { $($test)* }
|
|
}
|
|
$(single!($($values),+);)*
|
|
}
|
|
}
|
|
|
|
fn main() {
|
|
repeat! {
|
|
($arr $Ty); n, N; z, Z:
|
|
compare_evaluation!([_, x @ .., _], &$arr!(1, 2, 3, 4), Some(x), Option<&'static [$Ty]>);
|
|
compare_evaluation!([x, .., _], &$arr!(1, 2, 3, 4), Some(x), Option<&'static $Ty>);
|
|
compare_evaluation!([_, .., x], &$arr!(1, 2, 3, 4), Some(x), Option<&'static $Ty>);
|
|
|
|
compare_evaluation!([_, x @ .., _], &$arr!(1, 2), Some(x), Option<&'static [$Ty]>);
|
|
compare_evaluation!([x, .., _], &$arr!(1, 2), Some(x), Option<&'static $Ty>);
|
|
compare_evaluation!([_, .., x], &$arr!(1, 2), Some(x), Option<&'static $Ty>);
|
|
|
|
compare_evaluation!([_, x @ .., _], &$arr!(1), Some(x), Option<&'static [$Ty]>);
|
|
compare_evaluation!([x, .., _], &$arr!(1), Some(x), Option<&'static $Ty>);
|
|
compare_evaluation!([_, .., x], &$arr!(1), Some(x), Option<&'static $Ty>);
|
|
}
|
|
|
|
compare_evaluation!([N(x), .., _], &n!(1, 2, 3, 4), Some(x), Option<&'static u8>);
|
|
compare_evaluation!([_, .., N(x)], &n!(1, 2, 3, 4), Some(x), Option<&'static u8>);
|
|
|
|
compare_evaluation!([N(x), .., _], &n!(1, 2), Some(x), Option<&'static u8>);
|
|
compare_evaluation!([_, .., N(x)], &n!(1, 2), Some(x), Option<&'static u8>);
|
|
}
|