anchor.diff:          }
         }
       });
  -
  -    if (abortWalk) {
  -      return _AbortingSemanticsFragment(owner: this);
  -    }
   
       for (final _InterestingSemanticsFragment fragment in toBeMarkedExplicit)
         fragment.markAsExplicit();
  
positive.code:   /// Returns [_InterestingSemanticsFragment] describing the actual semantic
    /// information that this fragment wants to add to the parent.
    List<_InterestingSemanticsFragment> get interestingFragments;
  
    /// Whether this fragment wants to abort the semantics walk because the
    /// information in the tree are not sufficient to calculate semantics.
    ///
    /// This happens for subtrees that are currently kept alive by a viewport but
    /// not laid out.
    ///
    /// See also:
    ///
    ///  * [_AbortingSemanticsFragment], which sets this to true.
    bool get abortsWalk => false;
  }
  
  /// A container used when a [RenderObject] wants to add multiple independent
  
negative.code:   }
  
    bool get _needsGeometryUpdate => _ancestorChain.length > 1;
  }
  
  /// Helper class that keeps track of the geometry of a [SemanticsNode].
  