type Type struct {
Field map[string]string // map field name to type
Method map[string]string // map method name to comma-separated return types (should start with "func ")
Embed []string // list of types this type embeds (for extra methods)
Def string // definition of named type
}
Type 描述某种类型的字段和方法。如果在其中找不到该字段或方法,则接下来在嵌入列表中查找进行查找。