This issue anticipates a recent DFDL workgroup clarification on how discriminators/asserts of testKind pattern work.

This should be confirmed as an official errata or in the next draft of the DFDL spec before implementing this.

It is mentioned here because potentially the grammar has to change to accomodate it. I.e., the up front framing content must NOT be parsed before considering the statement annotations.

The point: the regex pattern match goes against the whole element representation, not against just the content region of it. Or in case of a sequence/choice, against the whole construct (starting from the start of the Left Framing).