I'm not so familiar with D, what is the state of this sort of feature? Is it a built-in tool, or are you talking about the ctod project I found?
In most languages, I've found that source translation features to be woefully lacking and almost always require human intervention. By contrast, it feels like Zig's `translate-c` goes the extra mile in trying to convert the source to something that Zig can work with as-is. It does this by making use of language features and compiler built-ins that are rather rare to see outside of `translate-c`.
Obviously the stacks of @as, @fooCast, and @truncate you are left with isn't idiomatic Zig, but I find it easier to start with working, yet non-idiomatic code than 90% working code that merely underwent a syntactic change.