Debug.Trace explicitly breaks referential transparency and its entire purpose is to penetrate the evaluation order out of the abstraction. It's a tool to penetr

Debug.Trace explicitly breaks referential transparency and its entire purpose is to penetrate the evaluation order out of the abstraction. It's a tool to penetrate the abstraction, much like a debugger. But the existence of such debugging tools does not mean the abstractions themselves are leaky, because these tools do not leak the abstraction as a side-effect, it is their only purpose. Performance analysis of pure algorithms is not a leak of the abstraction, if you consider the abstraction relates to the semantics, the result of the algorithm, and not how much resources it takes to execute. If you wish to know the resource use of your pure code, then none of the nice abstractions hold anymore, but most of the time, you don't need to.