If you wrote such syntax on top of Go, it would no longer be go, it would be a new language you created.
The go authors wouldn't accept it, the ecosystem wouldn't work with it, and it would be fighting an uphill battle rather than just using rust or building a new language.
> There are Rust compilers without the borrow checker
Then those compilers do not compile rust. They compile a bastardized version of rust whereby programs that are not valid rust programs can compile.
Also, can you name these non-borrowck-ing rust compilers? You say there's multiple, so you should be able to at least name one or two.
https://github.com/thepowersgang/mrustc is a Rust compiler without borrow checker.
In Rust, the borrow checker is too a separate static analysis stage and not directly tied to code gen. There are Rust compilers without the borrow checker.