rust/tests/ui/myriad-closures.rs

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// run-pass
// This test case tests whether we can handle code bases that contain a high
// number of closures, something that needs special handling in the MingGW
// toolchain.
// See https://github.com/rust-lang/rust/issues/34793 for more information.
// Make sure we don't optimize anything away:
// compile-flags: -C no-prepopulate-passes -Cpasses=name-anon-globals
// Expand something exponentially
macro_rules! go_bacterial {
($mac:ident) => ($mac!());
($mac:ident 1 $($t:tt)*) => (
go_bacterial!($mac $($t)*);
go_bacterial!($mac $($t)*);
)
}
macro_rules! mk_closure {
() => ((move || {})())
}
macro_rules! mk_fn {
() => {
{
fn function() {
// Make 16 closures
go_bacterial!(mk_closure 1 1 1 1);
}
let _ = function();
}
}
}
fn main() {
// Make 2^8 functions, each containing 16 closures,
// resulting in 2^12 closures overall.
go_bacterial!(mk_fn 1 1 1 1 1 1 1 1);
}