Summary & Key Takeaways ​

• The validator now fails compilation instead of warning when a template's markup would be restructured by the browser.
• This prevents desynced hydration and silently misplaced bindings in the DOM.
• Errors now provide a clear code frame pointing to the offending JSX.
• Universal text handling and hydration ID fixes from the compiler are also included.

Our Commentary ​

I love this change. Silently shipping broken hydration or misaligned bindings because of a warning buried in server logs is a nightmare. Forcing a compile-time error for invalid HTML markup is a huge win for developer experience. It's a clear signal that something is wrong, right when you write the code, which is exactly what we need from our tooling.