Keyboard shortcuts

Press ← or → to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

Pre-stabilization testing of the next solver and polonius alpha on CI

We want to improve the continuous test coverage of next solver and polonius alpha with a goal to stabilize them in 2026. To achieve this, we need to ensure these unstable features are well tested and continuously well tested so they do not regress.

This calls for a dedicated CI job x86_64-gnu-next-trait-solver-polonius which is blocking in PR CI and thus also Merge CI to catch regressions.

For more context, see:

What is tested

  • For the next solver:
    • We want to ensure we can build the standard library with the next solver.
    • We want to ensure we can bootstrap a full toolchain with the next solver.
    • We do both by building the stage 2 library with the next solver enabled at stage 1.
  • For the polonius alpha:
    • We run the UI test suite under the polonius compare mode, against the stage 1 compiler/std built with the next solver enabled.

Note

To reproduce failures locally:

$ RUSTFLAGS_NOT_BOOTSTRAP="-Znext-solver=globally" ./x build library --stage 2

$ RUSTFLAGS_NOT_BOOTSTRAP="-Znext-solver=globally" ./x test tests/ui --compare-mode polonius --stage 1

What failures and remedies might be specific to this combination?

  • This may yield new errors when using unstable features in the standard library or the compiler.
  • This may sometimes require blessing new tests, or in rare cases, adding test annotations or revisions.

Point of contact

If you have questions or need advice on a test failure in this job, please open a new topic in t-compiler zulip channel.