1. if you wish, you absolutely can check for "extra constraints" on a passed type (or even an anytype parameter) using comptime reflection and the @comptimeErro

1. if you wish, you absolutely can check for "extra constraints" on a passed type (or even an anytype parameter) using comptime reflection and the @comptimeError builtin. 2. if you want to restrict the use of a function to comptime (why you would want to is beyond me) it is possible to do with @inComptime builtin. the only tricky bit is that your function could try to call a function inaccessible to you because it's transitively restricted and you'd have a hard time noticing that from the code but it's not possible for that code to be compiled (barring errors by the zig team) so its more of an annoyance than a problem.