Johnni Winther
4ffe1b2768
This moves the ValueKind and NullValue interface to the util package and add the NullValue as an interface to the NullValue enum, which has now been renamed to NullValues. This prepares for reusing the stack checking mechanism from the StackListener in the inference visitor of the CFE. The adding of NullValue as an interface, allows for using ValueKind and NullValue that are specific to the types used in the stack. Change-Id: I7d6b3d3932753898d87ef774a95460832efdc969 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/279084 Commit-Queue: Johnni Winther <johnniwinther@google.com> Reviewed-by: Konstantin Shcheglov <scheglov@google.com> Reviewed-by: Jens Johansen <jensj@google.com>