anchor.diff:    }
   
     bool get _needsGeometryUpdate => _ancestorChain.length > 1;
  -}
  -
  -
  -/// [_SemanticsFragment] used to indicate that the current information in this
  -/// subtree is not sufficient to update semantics.
  -///
  -/// Anybody processing this [_SemanticsFragment] should abort the walk of the
  -/// current subtree without updating any [SemanticsNode]s as there is no semantic
  -/// information to compute. As a result, this fragment also doesn't carry any
  -/// semantics information either.
  -class _AbortingSemanticsFragment extends _InterestingSemanticsFragment {
  -  _AbortingSemanticsFragment({required RenderObject owner}) : super(owner: owner, dropsSemanticsOfPreviousSiblings: false);
  -
  -  @override
  -  bool get abortsWalk => true;
  -
  -  @override
  -  SemanticsConfiguration? get config => null;
  -
  -  @override
  -  void addAll(Iterable<_InterestingSemanticsFragment> fragments) {
  -    assert(false);
  -  }
  -
  -  @override
  -  void compileChildren({ Rect? parentSemanticsClipRect, Rect? parentPaintClipRect, required double elevationAdjustment, required List<SemanticsNode> result }) {
  -    result.add(owner._semantics!);
  -  }
  -
  -  @override
  -  void markAsExplicit() {
  -    // Is never explicit.
  -  }
   }
   
   /// Helper class that keeps track of the geometry of a [SemanticsNode].
  
positive.code:         }
        }
      });
  
      if (abortWalk) {
        return _AbortingSemanticsFragment(owner: this);
      }
  
      for (final _InterestingSemanticsFragment fragment in toBeMarkedExplicit)
        fragment.markAsExplicit();
  
negative.code:   /// Returns [_InterestingSemanticsFragment] describing the actual semantic
    /// information that this fragment wants to add to the parent.
    List<_InterestingSemanticsFragment> get interestingFragments;
  }
  
  /// A container used when a [RenderObject] wants to add multiple independent
  