This new function complements the existing function FindMoveStatements
by potentially generating additional "implied" move statements that aren't
written explicit in the configuration but that we'll infer by comparing
the configuration and te previous run state.
The goal here is to infer only enough to replicate the effect of the
"count boundary fixup" graph node (terraform.NodeCountBoundary) that we
currently use to deal with this concern of preserving the zero-instance
when switching between "count" and not "count".
This is just dead code for now. A subsequent commit will introduce this
into the "terraform" package while also removing
terraform.NodeCountBoundary, thus achieving the same effect as before but
in a way that'll get reported in the UI as a move, using the same language
that we'd use for an explicit move statement.
This is a first pass at implementing refactoring.ValidateMoves, covering
the main validation rules.
This is not yet complete. A couple situations not yet covered are
represented by commented test cases in TestValidateMoves, although that
isn't necessarily comprehensive. We'll do a further pass of filling this
out with any other subtleties before we ship this feature.
Martin Atkins