Three checks, and between them they account for every state Excel's fill menu shows:
Fill Months on a numeric selection, and Linear Trend on a date one.Linear Trend on a single cell.Fill Series on abc, def while leaving Copy Cells alone: nothing recognizes a series there, so the fill would
be a copy by another name.A filler's matches therefore has to answer could you fill from this if asked, which is
NOT always is this template already a series of my kind. The two come apart for a filler
that is never auto-detected: Fill Weekdays should be offered for a template of two weekend
dates — it means "give me business days from here", and the engine happily takes a Saturday
anchor — even though those two dates are not a weekday series. A filler outside
Types.Series's composite is only ever asked on the explicit path, so it should claim
permissively.
Whether
presetcan be offered for a selection holding these value types.