I just submitted a stackoverflow question on this topic, <https://stackoverflow.com/questions/76072831/how-can-you-get-the-sizeof-an-untyped-type-identifier-inside-a-macro>
I edited @PMunch's answer with how I ended up implementing it, but my edit wasn't accepted. It was essentially @choltreppe s answer of emitting a call to a secondary typed macro. My use case was a bitfield helper library I'm working on, I wanted the cleanest syntax that will pass the parser, but later to statically verify type sizes against that input to be able to produce helpful error messages.
