Allow flattening newtypes and as types

[cairomassimo]

Goal

1. Allow flattening newtypes if the inner type can be flattened. This matches serde_json behavior.
2. Allow flattening types with #[ts(as = "...")] if the referenced type can be flattened. This can be useful and (as far as I can tell) has no downsides.

Changes

• macros/src/types/newtype.rs: Add inline_flattened that delegates to the inner type
• macros/src/types/type_as.rs: Add inline_flattened that delegates to the as type
• macros/src/types/enum.rs: Restructure internally tagged enum handling to check for newtype variants first, ensuring they always use intersection syntax ({ "tag": "A" } & Type) rather than the flattened path
• Added tests in newtype_flatten.rs and type_as_flatten.rs

Checklist

• I have followed the steps listed in the Contributing guide.
• If necessary, I have added documentation related to the changes made.
• I have added or updated the tests related to the changes made.

[gustavo-shigueo]

Hi @cairomassimo thanks for the PR! We are already making a change (#474) to how we flatten structs with zero fields that touches some of the same areas of the code as you have here - specifically, the match expression in the enum file. Would you mind waiting until those changes are merged as to help us avoid a possible conflict and breaking change?

[cairomassimo]

Sure! The changes to the implementation are small anyway, and the test won't have any conflicts. Thanks for the quick response

…

On Sun, Feb 8, 2026, 21:10 Gustavo Shigueo ***@***.***> wrote: *gustavo-shigueo* left a comment (Aleph-Alpha/ts-rs#477) <#477 (comment)> Hi @cairomassimo <https://github.com/cairomassimo> thanks for the PR! We are already making a change (#474 <#474>) to how we flatten structs with zero fields that touches some of the same areas of the code as you have here - specifically, the match expression in the enum file. Would you mind waiting until those changes are merged as to help us avoid a possible conflict and breaking change? — Reply to this email directly, view it on GitHub <#477 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA7M2BKCIZ74E5FUCXSK4ET4K6C2BAVCNFSM6AAAAACUMYNAX6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQNRYGAYDMNBUGQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>