[nanolith]

> Again, no, it isn't. You seem to be severely underestimating the systemic impact of cache misses if you are considering them a "small" impact to efficiency.

You are severely overestimating the impact of cache misses if you think that all indirection must be eliminated and any use of pImpls at all is always wrong, as you seem to be implying.

> pImpls are the sort of thing you use at API boundaries to avoid leaking implementation details into users, but that's trading efficiency & complexity for a more stable API boundary. Scattering them throughout your code base would be like compiling with -O0.

It's a good thing that I never advocated using them everywhere then. Where did you read me saying this?

> Or, alternatively, using pImpls to optimize for compile time is a premature optimization.

Only if this is done by default, which I have not advocated for anywhere in this thread. I called it a tool in the toolbox. I mentioned it as one of several possibilities. Somehow you have translated this into "use pImpls everywhere", which is a strawman.