google/quiver-dart — pull request #138 by yjbanov (2014-05-21 16:47:05+00:00)
Title: Add isAssignableTo

`isAssignableTo` is a drop-in replacement for `isInstanceOf`. Unlike
`isInstanceOf` this matcher fails if the type parameter is malformed,
e.g. when it is not imported or contains a typo. This class does not
support matching on `Object` or `dynamic`.