There is in c++, too (std::ignore). Not sure why the author decided to go with the ancient void cast
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p29... aims to address that, but that won't be included until C++26 (which also includes _ as a sibling commenter mentions).
> We propose that when_ is used as the identifier for the declaration of a variable, non static class member variable, lambda capture or structured binding. the introduced name is implicitly given the [[maybe_unused]] attribute.
> In contexts where the grammar expects a pattern matching pattern,_ represents the wildcard pattern.
Some of the finer details (e.g., effect on lifetime and whether a _ variable can be used) differ, though.
In modern Rust you don't need the let here because you're allowed to do the pattern match anywhere, and as I said _ is simply a pattern that matches anything. So we could omit the let keyword, but people don't.