How to make invariant switchable

[bearophile]

Max Samukha:
> Why would you want to leave asserts in a release build while they are
> supposed to be used for debugging?

If you look around on internet you will find lot of people that like to keep assertions in the final programs too.
Is DMD itself compiled with asserts left inside? When DMD doesn't work if often spits out a file + line number that I think come from an assert.

Bye,
bearophile