What version of gRPC and what language are you using?

gRPC head, C++

What operating system (Linux, Windows,...) and version?

Linux

What runtime / compiler are you using (e.g. python version or version of gcc)

clang

What did you do?

This is a cleanup issue.

re: #18373 ; create_channel_posix.h

Rule of thumb: no public API should be behind an ifdef like this. The actual implementation might differ depending on said define, and assert with a message saying this feature isn't enabled in this version, but the API/ABI shouldn't mutate depending on a compilation flag.

What did you expect to see?

API/ABI shouldn't mutate depending on a compilation flag.

What did you see instead?

API/ABI mutated depending on a compilation flag.

Make sure you include information that can help us debug (full error message, exception listing, stack trace, logs).