these are the ast structures that have a selectionset collection, which maybe different to the objects contained in the selectionset *OperationStmt) AppendSelectionSet(ss SelectionSetProvider) { *FragmentStmt) AppendSelectionSet(ss SelectionSetProvider) { *InlineFragment) AppendSelectionSet(ss SelectionSetProvider) { *Field) AppendSelectionSet(ss SelectionSetProvider) {.