https://issues.dlang.org/show_bug.cgi?id=24673

          Issue ID: 24673
           Summary: [DIP1000] Usage of `scope` parameters should require
                    an explicit `@safe`-ty annotation
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: qs.il.paperinik@gmail.com

On functions, annotating parameters `scope` or `in` should require the function be annotated with `@safe`, `@trusted` or `@system`. With `@system` being the default, it makes it easy to specify the outward guarantee that the parameter doesn’t escape without it being enforced.

--