Rust stable, macro bomb

[denisandroid]

Rust:
rustc 1.34.0-nightly (097c04c 2019-02-24)
rustc 1.33.0 (2aa4c46 2019-02-28)

PlayGround:
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=14643a4834e5ae92f13e1a1de5c5becb

(OUT) https://pastebin.com/Bv13Lf0M (signal: 9, SIGKILL: kill)

Eng:
Accidentally identified "macro bomb".
It completely clogs the computer's RAM, even on a stable version of Rust and when using RLS.

No warnings or errors.

PlayGround does not even work on a stable version (output is attached), please solve the problem.

Ru:
Случайно выявлена "macro bomb".
Забивает полностью ОЗУ компьютера, даже на стабильной версии Rust и при использовании RLS.

Никаких варнингов или ошибок.

Не отрабатывает PlayGround даже на стабильной версии (вывод прилагается), просьба решить проблему.

[jonas-schievink]

The second macro arm puts @RAW; between each token of the input, so the first arm is never actually reached (you can remove it). This means that for every expansion of the second arm, the number of tokens is multiplied by 4. The recursion limit doesn't help in this case before the memory usage grows exponentially.

This also looks like a duplicate of #51754, so closing in favor of that.