E4010

pub is not allowed on default implementation for traits. The default implementation has the same visibility as the trait itself.

错误示例：

pub(open) trait Stringer {
  stringify(Self) -> String
}

pub impl Stringer with stringify(_self) { "hey" }

In the example above, the pub keyword is used on the default implementation of the Stringer trait, which is not allowed.

建议

移除 pub 关键字，使默认实现与特性本身具有相同的可见性：

pub(open) trait Stringer {
  stringify(Self) -> String
}

impl Stringer with stringify(_self) { "hey" }