An example of Clang error messages

[grauzone]

Walter Bright wrote:
> bearophile wrote:
>> Walter Bright:
>>> Yeah, I wrote a C++ compiler back in 1987. It compiled itself, too!
>>> The hard work of implementing C++ correctly was just beginning,
>>> though.
>>
>> C'mon Walter, give them some credit, wish them some luck, I think
>> they will be able to compile a good percentage of Boost in less than
>> 15 years ;-)
> 
> Given a solid C compiler, writing a reasonably compliant C++ compiler 
> takes an additional 10 man years, in the best of circumstances. More 
> reasonably, 20.

How many man years would you assume writing a full D compiler takes? 
(Frontend starting from scratch, using an existing backend.)