Well, you can use strong types that separate e.g. String/SQLQuery/XMLBlob from one another, and then have very narrow conversion routines that are heavily audit

Well, you can use strong types that separate e.g. String/SQLQuery/XMLBlob from one another, and then have very narrow conversion routines that are heavily audited to handle them safely. You can then use type directed programming to make conversions a little simpler (sometimes). This can give the appearance of things being handled "by the compiler", e.g. because typeclass resolution can be used to pick an appropriate instance. But it's not magical or anything. Maybe that's basically what you meant anyway. Any statically typed language can do the first part, the second part is a tad less trivial (and arguably a footgun in some scenarios, but that's another discussion.)