fastcgo

https://github.com/petermattis/fastcgo, which is now 7 years old seems to do something similar without the need to about obscure CGO FFI configuration. It also seems to be more generally applicable for any language with C interop. There had been an issue for having something similar in the language itself - https://github.com/golang/go/issues/42469, but the Golang compiler team rejected it. If you have followed similar discussions around this with the Golang compiler team, you will notice a pattern of interaction that strongly indicates that they are very much opposed to ever accepting this into the compiler.

Cgo exists because goroutine stacks are small and grow on demand. C/C++ expect large fixed size stacks. While you can technically call into C++ without going through cgo (see https://github.com/petermattis/fastcgo), you can't avoid the stack problem. Cgo solves it by switch from the goroutine stack to the stack of the thread underlying the goroutine.