Why do you write D2 compiler using C++ language?

[Rikki Cattermole via Digitalmars-d]

On 14/12/2014 12:38 a.m., ddj wrote:
> You already have better D1.

The usage of c++ for dmd front end is the original language for it. Aka 
it would be rather hard to write a front end for D without a D compiler.
Its currently being ported over to D.

As for why it wasn't changed over when D2 started. Probably was seen as 
too much work at the time.