Implemented and removed. A render-phase flag cleared on a microtask is
still set when React runs effects, so islands writing from an effect —
the documented correct pattern — would throw. The flag also cannot be
set for an island's own re-renders, so real violations pass silently.
Detecting React's render phase reliably needs React internals, which is
not acceptable in a shipped framework. React already reports the real
hazard, and the getSnapshot caching requirement covers the loop case.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
ClintchizandClaude Opus 5
5f66c8129c