Improve "Improve Contract Syntax" DIP 1009

[Adam D. Ruppe]

On Saturday, 4 November 2017 at 15:27:39 UTC, Ola Fosheim Grøstad 
wrote:
> No, Jonathan is correct. The postcondition should be able to 
> access values as they were stated in the precondition.

Yes, they should be able to access values, but D's limitations on 
this doesn't make them useless or replaced by unittests. They do 
a different job than unittests.