[edwintorok]

I think that statement is better viewed in lights of refactoring or changing existing code. If the code worked/compiled before, and I made a change that still compiles, I can be reasonably confident it didn't break something else accidentally (assuming the program was reasonably well designed to begin with). It makes reviewing pull-requests much easier.

Doing so in other programming languages always makes me nervous, in C an innocuous change could introduce some memory corruption bug because you broke an implicit invariant of the code, in Python it could raise a type error when called in an unexpected way. To review a pull-request you have to look usually at the entire file (or sometimes the entire project), and even then you can't be sure.

As for the logic bugs: that is what tests are for.