Nightly Dotty workflow of 2022-02-05 failed

[github-actions]

See https://github.com/lampepfl/dotty/actions/runs/1798199876

[som-snytt]

Probably spurious. What an interesting niche of the test regime. It's been a few years since I man bash. The result of echo ok is "out of order". It says echo can fail on i/o. Probably the expansion of grep means the grep is what failed, but maybe just transient error. Also TIL -Ythrough-tasty.

testing that missing source file does not crash message rendering
+ /__w/dotty/dotty/project/scripts/../../project/scripts/sbt 'scalac /tmp/tmp.E0crJ7tsXP/A.scala -d /tmp/tmp.SpCWsgYdVY'
[info] welcome to sbt 1.6.1 (Private Build Java 16)
[info] loading global plugins from /root/.sbt/1.0/plugins
[info] loading settings for project dotty-build-build from build.sbt ...
[info] loading project definition from /__w/dotty/dotty/project/project
[info] loading settings for project dotty-build from build.sbt,plugins.sbt ...
[info] loading project definition from /__w/dotty/dotty/project
[info] loading settings for project scala3 from build.sbt ...
[info] resolving key references (30898 settings) ...
[info] set current project to scala3 (in build file:/__w/dotty/dotty/)
[info] running (fork) dotty.tools.dotc.Main -classpath /root/.cache/coursier/v1/https/scala-webapps.epfl.ch/artifactory/central/org/scala-lang/scala-library/2.13.8/scala-library-2.13.8.jar:/__w/dotty/dotty/library/../out/bootstrap/scala3-library-bootstrapped/scala-3.1.3-RC1-bin-SNAPSHOT-nonbootstrapped/scala3-library_3-3.1.3-RC1-bin-SNAPSHOT.jar /tmp/tmp.E0crJ7tsXP/A.scala -d /tmp/tmp.SpCWsgYdVY
[success] Total time: 5 s, completed Feb 5, 2022, 4:29:25 AM
+ rm /tmp/tmp.E0crJ7tsXP/A.scala
+ /__w/dotty/dotty/project/scripts/../../project/scripts/sbt 'scalac -classpath /tmp/tmp.SpCWsgYdVY -d /tmp/tmp.SpCWsgYdVY /tmp/tmp.E0crJ7tsXP/B.scala'
+ echo ok
+ grep -qe B.scala:2:7 /tmp/tmp.PlAZKzS2ah
ok
Error: Process completed with exit code 1.

[smarter]

Duplicate of #14406.