rust/library/alloctests/testing/macros.rs

macro_rules! struct_with_counted_drop {
    ($struct_name:ident$(($elt_ty:ty))?, $drop_counter:ident $(=> $drop_stmt:expr)?) => {
        thread_local! {static $drop_counter: ::core::cell::Cell<u32> = ::core::cell::Cell::new(0);}

        struct $struct_name$(($elt_ty))?;

        impl ::std::ops::Drop for $struct_name {
            fn drop(&mut self) {
                $drop_counter.set($drop_counter.get() + 1);

                $($drop_stmt(self))?
            }
        }
    };
}

pub(crate) use struct_with_counted_drop;