Fragile tests should compile
concprog001 is marked as fragile and fails on CI with
Converter.hs:113:35: error: Ambiguous occurrence ‘yield’ It could refer to either ‘GHC.Data.Stream.yield’, imported from ‘GHC.Data.Stream’ at Converter.hs:4:1-22 or ‘Control.Concurrent.yield’, imported from ‘Control.Concurrent’ at Converter.hs:6:1-25 (and originally defined in ‘GHC.Conc.Sync’)
This is a concurrency test. I doubt that it is flaky because of an ambiguous import.
We should require that fragile tests compile successfully, otherwise they should fail loudly.