go / ast软件包中的Doc和Comment有什么区别？

Question

I am using the go/ast and go/parser package to do something, but i am puzzled about the difference between Doc and Comment.

Is the first line of comments a Doc, then others as Comment?
Here is a sample:

TypeSpec struct {
    Doc     *CommentGroup // associated documentation; or nil
    Name    *Ident        // type name
    Type    Expr          // *Ident, *ParenExpr, *SelectorExpr, *StarExpr, or any of the *XxxTypes
    Comment *CommentGroup // line comments; or nil
}

Answer 1

From src/go/ast/ast.go#L70-L75:

// A CommentGroup represents a sequence of comments
// with no other tokens and no empty lines between.

Following Godoc: documenting Go code:

• Doc is one or several continuous lines of comments (// ...) before the TypeSpec

write a regular comment directly preceding its declaration, with no intervening blank line

// A TypeSpec node represents a type declaration (TypeSpec production).
^^^^^^^^^^^^...
TypeSpec struct {

• Comment is a comment associate to the field itself, starting on the same line, but which can spread over multiple continuous lines (hence "CommentGroup")

  Name    *Ident        // type name
                        ^^^^^^^^^^^
                        // the comment associated to Name
                        // could go on over several lines