Fred Brooks discussed this in the unfortunately named pun "The Mythical Man-Month". Most of the gray beards have read it, ask to borrow it, it will make their day. The punchline was on the IBM 360 they stopped fixing bugs when the fix cause the same or more bugs than the unfixed bug, which soon became all bugs.

Well aware of Brooks, when the loop var semantics were changed Go did an analysis showing that many more bugs were fixed than created by the change.