This playground showcases behavior of different Error handling operators available in Combine framework:
assertNoFailurecatchmapErrorsetFailureTyperetryreplaceError
SharedCode.swift file (located in Sources) contains a definition of used Subject, errors and closures used in Playground's pages files.
Blog post about errors in Combine which describes examples from this playground
Should work well on Xcode 11.0 beta 4 (11M374r) and above.