A Programming Language Build for Security: SPARK
There is already a programming language build for security, which has existed since the 80's. Spark is a language build on top of Ada, an already secure language, and added mathematical sound proving mechanism. And other security features.
https://en.wikipedia.org/wiki/SPARK_%28programming_language%29
Here is a sample code:
procedure Sample(x, y : in out float)
--# derives x from y &
--# y from x;
is
z: float;
begin
z := x; x := y; y := t;
end sample;
This is why I agree with Anon. on DARPA's intentions. If they are able to complete this project they will be able to find, even if miner, errors in code and use it for their advantage for a relative miner cost. Which sound pretty good considering how they now have to go to the open market.