[sidlls]

https://cs.opensource.google/go/go/+/refs/tags/go1.21.6:src/...

[derekperkins]

I wouldn't classify type assertion as reflection. It's a super fast type check of the object header, not dynamic reflection.

[Thaxll]

But this is a detail of implementation, user code does not use reflection with errors.

[sidlls]

That "detail of implementation" is what is used by user code, e.g., `myError.As(...)` uses reflection, implicitly.

[Thaxll]

Then what? It has 0 performance impact, we're talking about error handling here, it's rare and not in hot path.

[sidlls]

It does not have 0 performance impact, it's not rare, and in applications that are in the hot path, error handling is also in the hot path.

[Thaxll]

No, it only executes when you enter the err != nil block so it's almost never called, again 0 impact on performance.