swift

d2529024 - [move-only] Eliminate dead field.

[move-only] Eliminate dead field. Originally this was a method to determine if we had emitted a diagnostic when running our gather visitor. It was pretty footgunny since one could easily forget to set it. Instead of doing that, we now maintain a counter in the diagnostic emitter that counts how many diagnostics we have emitted and use that to determine if during the walk if we emitted any additional diagnostics.