Bug 16520 – static foreach should be more explicit

Currently, one can hardly tell when reading a `foreach` statement if it's executed at CT or not. One should know that the argument passed is actually a tuple. Even when it's known, there is a risk that a later change can change this property. I propose we implement a `static foreach` construct, which ensures that a `foreach` is executed at compile time. The roadmap could look like the following: - Support for `static foreach`: Old `foreach` over tuple still have the same effect, but one can use the `static` keyword to ensure this specific behaviour is used. If not, the compiler produces an error; - Later on, deprecate `foreach` on tuple without `foreach`. - Then make it an error - Later on, we can consider allowing it, but it will mean it gets executed at runtime This would not introduce any new feature in `static foreach` - That can be done later if wanted. But would make this obscure construct a bit less obscure.

Static foreach has been added to the language. I'll close this as fixed.