anchor.diff:  
           context._vaoExtension.bindVertexArray(vao);
   
  -        if (glIndexList != null) {
  -          context._bindIndexList(glIndexList);
  -        }
  -
           final attributes = glProgram.attributes;
           final attributesLength = attributes.length;
           final tables = new Set<AttributeDataTable>();
  
positive.code:         glPrimitives.vao = vao;
        }
      } else {
        context._bindIndexList(glIndexList);
  
        // TODO: find better way than creating a new set every time.
        final unusedAttribLocations = context._enabledAttributeLocations.toSet();
  
  
negative.code:     }
  
      if (glIndexList != null) {
        context._bindIndexList(glIndexList);
  
        final indexList = glIndexList.indexList;
  
        if (indexList.indexSize == IndexSize.unsignedByte) {
  