Strange F# Error on Mono/Xamarin

While dipping my toes into F# some time ago, I ran into a compile-time error that I couldn't explain or find a solution for: "Error FS0010: Unexpected keyword 'open' in implementation file (FS0010)". I was just building the Hello World app that comes with MonoDevelop out of the box. After some tooling around on StackOverflow and coming up short, the only thing I could think was, "Maybe it's a Mono bug, it's not in their issue tracker so I should just compile everything from source to be sure." Long story short, that was not the problem so don't waste your time; Mono 3.10+ is more than adequate. The issue was because I had a hyphen in my project name and the AssemblyInfo.fs file was improperly formatted because of it.

The work-around was a simple as subing in an underscore for the hyphen.

This may indicate a tooling issue in MonoDevelop/Xamarin Studio so I'll research it more and submit a ticket but the underscore switcheroo works in a pinch.