When working with Roslyn, I will often have a node that is in the CompilationUnitSyntax but not the SemanticModel or vice-versa.  (Or I can only pull the nodes out with operations of one or the other--For example if you need type info from a semantic model, the node querying on has to exist in the SemanticModel's tree)

I can see why they did it for immutability and all that, but how the heck do you consistently go back and find the same token from one tree to another??  If you modify either tree, you have to retrieve the node you were working with somehow.  What's the best way to do it????


Question: What brass band instruments can a cornet player feasibly cover on short notice?
Answer: Your biggest problem may be reading in the bass clef. The valves on most (I think) 3 valved brass do the same job, and the dots will be in a key which compensates for the pitch (as in, if it's a Bb instrument, and the tune is in C, the dots will be written in D ).

Don't feel the embouchure will be a big deal, and you'll quickly re-adapt after. In fact, you may enjoy it so much that you go out and get a - valve trombone / tuba /etc.

It sounds like a great opportunity : grab it with both hands.You can always play quietly or mime in the 'hard bits' !