dart-lang/sdk@f4a72bfc64 [cfe] Don't crash on access to extension fields
dart-lang/sdk@41c11716b0 [kernel] Make round-trip script work; improve fastas compare dill tool
dart-lang/sdk@9276d50fdc [cfe] Remove Severity.errorLegacyWarning
dart-lang/sdk@bc8b12e43b [cfe] Handle privacy in extension lookup