encoding/json: Struct behind interface embedding behaves differently to struct-only embedding

[gopherbot]

by pronox:

Marshaling flattens embedded struct fields just fine but fails with struct fields
abstracted by interface types. In essence:

    struct{ someStruct }{someStruct{}} // properly flattened

    type Any interface{}
    struct{ Any }{someStruct{}} // not flattened: "Any":{ ... }

See http://play.golang.org/p/-ZtaIGe7QJ for an example.

I think if the underlying type of the embedded interface is a struct the output should
be flattened.

go version devel +9c65fe4ce5a2 Wed Jan 29 09:51:31 2014 +0900 linux/amd64

[rsc]

Comment 1:

Embedded interfaces and embedded structs are just different. Here is a version of your
program demonstrating the difference. If we "flatten", then how do we know how to
unmarshal? http://play.golang.org/p/orp7cvQplU

Status changed to WorkingAsIntended.