[error] The method ‘retype’ isn’t defined for the class ‘Stream‘

The deprecated retype method was removed as of Dart 2.0.0-dev.62.0 released June 13. Running tests in Chrome using pub run build_runner test -- -p chrome now fail at runtime with

Error compiling dartdevc module:rxdart|lib/futures.ddc.js

[error] The method 'retype' isn't defined for the class 'Stream<T>'. (package:rxdart/src/observable.dart, line 1909, col 33)

If you’re not ready to remove the retype method from rxdart then maybe your implementation of retype can be explicitly call cast.