Any way to print compile-time generated code?

[Chris Williams]

On Monday, 10 March 2014 at 18:25:10 UTC, Adam D. Ruppe wrote:
> Change the mixin(x) line to pragma(msg, x);. It will then print 
> out the generated string at compile time instead of mixing it 
> in so you can take a look at it.

That just gives me an error:

source/app.d(29): Error: Cannot interpret 
ProtocolBufferFromString!"\x0a    message Person {\x0a      
required string name = 1;\x0a      required int32 id = 2;\x0a     
  optional string email = 3;\x0a\x0a      enum PhoneType {\x0a     
    MOBILE = 0;\x0a        HOME = 1;\x0a        WORK = 2;\x0a      
}\x0a\x0a      message PhoneNumber {\x0a        required string 
number = 1;\x0a        optional PhoneType type = 2 [default = 
HOME];\x0a      }\x0a\x0a      repeated PhoneNumber phone = 
4;\x0a    }\x0a" at compile time