Most Flutter routers were architected before Dart 3 had sealed types and pattern matching. One has been redesigned around them. Here's the value-oriented shape no one has built yet.
Flutter's two most-adopted routing libraries — go_router and auto_route — were architected in a world before Dart had sealed classes, exhaustive pattern matching, and records. Both shipped their core API in 2021–2022, and both still organize themselves around the same primitive: a string path, parsed at runtime, with type safety bolted on via build_runner.