bad error message relating to unbound non-Unit values

[aryairani]

This error message is super wrong. It's trying to tell my I forgot to bind or discard my non-Unit result on the blue line. Calling it the "1st argument to Cloud.main" is also misleading. I only figured it out after realizing the 1st argument to Cloud.main isn't supposed to be either of those.

• ucm --version 491f151

[ceedubs]

I think that this is the same issue as #5686