anchor.diff:      final List<PlaceholderDimensions> placeholderDimensions = List<PlaceholderDimensions>.filled(childCount, PlaceholderDimensions.empty, growable: false);
       int childIndex = 0;
       // Takes textScaleFactor into account because the content of the placeholder
  -    // span will be scale up when it paints.
  +    // span will be scaled up when it paints.
       width = width / textScaleFactor;
       while (child != null) {
         final Size size = child.getDryLayout(BoxConstraints(maxWidth: width));
  
positive.code:     // Leave height unconstrained, which will overflow if expanded past.
      BoxConstraints boxConstraints = BoxConstraints(maxWidth: constraints.maxWidth);
      // The content will be enlarged by textScaleFactor during painting phase.
      // We reduce constraint by textScaleFactor so that the content will fit
      // into the box once it is enlarged.
      boxConstraints = boxConstraints / textScaleFactor;
      while (child != null) {
  
negative.code:         case ui.PlaceholderAlignment.belowBaseline: {
            assert(RenderObject.debugCheckingIntrinsics,
              'Intrinsics are not available for PlaceholderAlignment.baseline, '
              'PlaceholderAlignment.aboveBaseline, or PlaceholderAlignment.belowBaseline.');
            return false;
          }
          case ui.PlaceholderAlignment.top:
  