https://issues.dlang.org/show_bug.cgi?id=19292

          Issue ID: 19292
           Summary: Mixin expressions should take an argument list the
                    same as pragma(msg) does
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: bugzilla@digitalmars.com

Mixin expressions are currently limited to being strings:

  https://dlang.org/spec/expression.html#mixin_expressions

While they should accept what the more flexible pragma(msg) does:

  https://dlang.org/spec/pragma.html#msg

This will make more complex mixin expressions easier to write without depending on Phobos for formatting, and will run faster and require less memory for CTFE to evaluate.

--