[bryanlarsen]

The "2018 edition" of Rust made breaking changes to the syntax (but the core stayed compatible, so 2015 edition and 2018 edition Rust can be used simultaneously on the same project).

They then said that they'd probably do the same thing in 2021.

Now they're debating whether a 2021 edition is needed since there aren't any breaking changes with broad support except for the removal of deprecated syntax and APIs.

This is strong evidence that the answer to your question is "no".

[steveklabnik]

I don’t think there’s consensus around very large things, but there are some regrets that are commonly expressed about smaller stuff. For example, lots of people think the PartialEq/Eq split was a mistake. I like to half-joke that String should have been StrBuf. Macros have several flaws and are under-developed, etc.

There are also some thoughts about Rust-like languages with some differences, see https://boats.gitlab.io/blog/post/notes-on-a-smaller-rust/ as a prominent example.

[k__]

I saw that the Piston developers created Dyon which could be seen as a Lua in the Rust spirit. No garbage collection, only lifetimes.

https://github.com/PistonDevelopers/dyon#list-of-features