message: document that fuss tests are flaky, and how to report.
diff: @@ -16,6 +16,13 @@ use proptest::collection::vec;
  use proptest::prelude::*;
  proptest! {
  + /// NOTE: proptest is a form of fuzz testing. It generates random input and makes shore that
  + /// certain universal truths are upheld. Therefore, it can pass when there is a problem,
  + /// but if it fails then there really is something wrong. When testing something as
  + /// complicated as the resolver, the problems can be very subtle and hard to generate.
  + /// We have had a history of these tests only failing on PRs long after a bug is introduced.
  + /// If you have one of these test fail please report it on #6258,
  + /// and if you did not change the resolver then feel free to retry without concern.
  #![proptest_config(ProptestConfig {
  // Note that this is a little low in terms of cases we'd like to test,
  // but this number affects how long this function takes. It can be
  @@ -34,6 +41,7 @@ proptest! {
  .. ProptestConfig::default()
  })]
  + /// NOTE: if you think this test has failed spuriously see the note at the top of this macro.
  #[test]
  fn passes_validation(
  PrettyPrintRegistry(input) in registry_strategy(50, 20, 60)
  @@ -51,6 +59,7 @@ proptest! {
  }
  }
  + /// NOTE: if you think this test has failed spuriously see the note at the top of this macro.
  #[test]
  fn minimum_version_errors_the_same(
  PrettyPrintRegistry(input) in registry_strategy(50, 20, 60)
  @@ -100,6 +109,7 @@ proptest! {
  }
  }
  + /// NOTE: if you think this test has failed spuriously see the note at the top of this macro.
  #[test]
  fn limited_independence_of_irrelevant_alternatives(
  PrettyPrintRegistry(input) in registry_strategy(50, 20, 60),
  