使用带有显式构造函数 C++ 的初始值设定器列表初始化结构时出错

问：

我有这样的结构

struct Example {
    Example() = default;

    explicit Example(const cv::Point2f& landmark,
                      float Score = 0.0f,
                      float visibilityScore = 1.f,
                      float threshold = 0.5f)
        : point(landmark),
          score(Score),
          visibilityScore(visibilityScore),
          threshold(visibilityThreshold) {}

    cv::Point2f point{0, 0};
    float score{0.0f};
    float visibilityScore{1.f};
    float threshold{0.5f};
};

当我尝试像下面一样单独初始化时，没有编译问题 -

Example eg = {};
eg.point = cv::Point2f(0,0);
eg.visibilityScore = 2.f;
eg.score = 3.f;
eg.threshold = 0.5f; 

当我尝试如下所示的括号初始值设定项列表时，出现构建错误 -

Example eg = {
.point = cv::Point2f(0, 0),
.score = 3.f,
.visibilityScore = 2.f,
.threshold = 0.5f};

错误-

no matching constructor for initialization of Example
note: candidate constructor not viable: cannot convert argument of incomplete type 'void' to 'const cv::Point2f' (aka 'const Point_<float>') for 1st argument
note: candidate constructor (the implicit copy constructor) not viable: requires 1 argument, but 4 were provided
note: candidate constructor not viable: requires 0 arguments, but 4 were provided

问题 - 这与第一个构造函数 arg 有关吗？explicitconst&