[dontmerge] Introduce a bug on top of #864 to see if cirrus catches it #887

1. 
   sipa commented at 0:14 am on January 30, 2021: contributor
2. ci: Add support for Cirrus CI d35a494cd9
3. ci: Enable simple cache for brewing valgrind on macOS 21353f75af
4. ci: Remove support for Travis CI

   So long, and thanks for all fish!

   7ef77c1f31
5. ci: Refactor Nix shell files 7f6f0c2060
6. Introduce bug in exhaustive tests 46c07ccea5
7. sipa cross-referenced this on Jan 30, 2021 from issue Add support for Cirrus CI by real-or-random
8. sipa closed this on Jan 30, 2021

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9. jonasnick referenced this in commit f8c0b57e6b on Jan 30, 2021

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sipa