自定义的struct，可以比较；有些限制如下（比较的不一致性）

• float 值 NaN不等于NaN
• func Type funcA 不等于 func Type funcA
• 包含Array，struct, interface

In general DeepEqual is a recursive relaxation of Go's == operator. However, this idea is impossible to implement without some inconsistency. Specifically, it is possible for a value to be unequal to itself, either because it is of func type (uncomparable in general) or because it is a floating-point NaN value (not equal to itself in floating-point comparison), or because it is an array, struct, or interface containing such a value.

基于以上说明的不确定性，能不能自定义相等（==）运算符？
答案：不行，go 有严格的==运算符设计，无法重载或自定义相等运算符，见：https://golang.org/ref/spec#Comparison_operators

如何实现自定义相等比较，曲线救国，如下方法：

• 使用reflect.DeepEqual方法，有些限制见文档：https://golang.org/pkg/reflect/#DeepEqual
• 用自定义实现DeepEqual方法，

go type identity 类型比较

go spec定义的类型比较：https://golang.org/ref/spec#Type_identity

参考文档：

• https://stackoverflow.com/questions/20309751/is-it-possible-to-define-equality-for-named-types-structs
• https://golang.org/ref/spec#Comparison_operators