go/src/reflect/visiblefields.go

// VisibleFields returns all the visible fields in t, which must be a
// struct type. A field is defined as visible if it's accessible
// directly with a FieldByName call. The returned fields include fields
// inside anonymous struct members and unexported fields. They follow
// the same order found in the struct, with anonymous fields followed
// immediately by their promoted fields.
//
// For each element e of the returned slice, the corresponding field
// can be retrieved from a value v of type t by calling v.FieldByIndex(e.Index).
func VisibleFields(t Type) []StructField { … }

type visibleFieldsWalker …

// walk walks all the fields in the struct type t, visiting
// fields in index preorder and appending them to w.fields
// (this maintains the required ordering).
// Fields that have been overridden have their
// Name field cleared.
func (w *visibleFieldsWalker) walk(t Type) { … }