https://issues.dlang.org/show_bug.cgi?id=24658

          Issue ID: 24658
           Summary: _aaRange cannot be interpreted at compile time,
                    because it has no available source code
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: minor
          Priority: P1
         Component: druntime
          Assignee: nobody@puremagic.com
          Reporter: jeremy@baxters.nz

Associative arrays cannot be iterated over at compile time. This is because the implementation of the range interface for AAs is private.

    enum range = ["a": "b"].byKey();

    void main()
    {
    }

This code fails on DMD 2.108.0 with:

    object.d(3130): Error: `_aaRange` cannot be interpreted at compile time,
because it has no available source code

--