The idea for DAFFODIL-2277 is that we want to create a warning if there
is a discriminator on a sequence AND that sequence is non-empty. This is
because a discriminator on a non-empty sequence is evaluated AFTER the
contents are parsed, which is often unintuitive since the discriminator
appears BEF
I'm new to Daffodil, and trying to learn my way around the code.
I have picked up Daffodil-2277 Warning needed for misplaced discriminators.
Can you give me a hook into the code where schema elements are evaluated so
that I can learn how to detect the position of specific elements in the schema
