Recommend using runtimeType in hash_and_equals (#1943)
Recommend using runtimeType in hash_and_equals (#1943)

> Using `is` in `operator ==` is usually wrong as it makes the `==` operator asymmetric.
https://github.com/dart-lang/sdk/issues/36004#issuecomment-557958476
dart-lang/linter,dart-lang/linter