Eager macro-expansion failure: (error "(erc-response\\.contents parsed) is not a valid place expression")

I can work around this by putting (require 'erc) and the function definition in different 'when' blocks, but it's not ideal.

The erc-response struct is defined in erc-backend.el, which is loaded by erc.el.

Putting (require 'erc) inside of a 'when' statement along with code that relies on functions provided by a struct defined by a file it loads seems to trigger the problem.