anchor.diff:  }
   ''';
   
  -}
  +
  +
  +}
  
positive.code:   RenderingContext gl;
    Program program;
    bool success = true;
    WebGlRenderingSystem(this.gl, Aspect aspect) : super(aspect);
    @override
    void initialize() {
      var vShader = createShader(RenderingContext.VERTEX_SHADER, vShaderSource);
      var fShader = createShader(RenderingContext.FRAGMENT_SHADER, fShaderSource);
  
      program = gl.createProgram();
      gl.attachShader(program, vShader);
      gl.attachShader(program, fShader);
  
negative.code:     }
    }
  
    Shader _createShader(int type, String source) {
      var shader = gl.createShader(type);
      gl.shaderSource(shader, source);
      gl.compileShader(shader);
  