Is this a bug when creating proxies in classes?

[via Digitalmars-d-learn]

On Monday, 25 August 2014 at 18:10:33 UTC, Gary Willoughby wrote:
> :!rdmd --force -de -debug -w test.d
> /usr/include/dmd/phobos/std/typecons.d(4043): Error: template 
> instance isArray!(typeof(a)) template 'isArray' is not defined
> test.d(7): Error: mixin test.Foo.Proxy!(foo) error instantiating
> Failed: ["dmd", "-de", "-debug", "-w", "-v", "-o-", "test.d", 
> "-I."]
>
> Can anyone else confirm or am i doing something wrong. I'm 
> using DMD 2.066.0 64bit Ubuntu 14.04.

It stopped working after this PR was merged:

https://github.com/D-Programming-Language/phobos/pull/1899

But I suspect that something else is going on. The PR only 
introduced the call to `isArray` into `std.typecons.Proxy`.