clippy "this lint expectation is unfulfilled" in CI

By Kaveh Alemi·Latchkey

The #[expect(lint)] attribute asserts a lint will fire there. If the code no longer triggers it, the unfulfilled_lint_expectations lint reports "this lint expectation is unfulfilled", which fails under denied warnings.

What this error means

clippy reports "warning/error: this lint expectation is unfulfilled" pointing at an #[expect(...)] attribute, even though that code looks fine.

error: this lint expectation is unfulfilled
 --> src/lib.rs:1:11
  |
1 | #![expect(clippy::needless_return)]
  |           ^^^^^^^^^^^^^^^^^^^^^^^^
  = note: `-D unfulfilled-lint-expectations` implied by `-D warnings`

Common causes

The expected lint no longer fires

Code under #[expect(lint)] was changed so the lint no longer triggers, leaving the expectation unfulfilled.

A stale expect attribute after a refactor

A refactor removed the construct the lint targeted, but the #[expect(...)] annotation was left in place.

How to fix it

Remove the stale expect attribute

1. Locate the #[expect(...)] named in the message.
2. Remove it if the code no longer needs to suppress that lint.
3. Re-run clippy to confirm the expectation lint is gone.

cargo clippy -- -D warnings

Switch to allow if you truly want suppression

If you want to suppress the lint regardless of whether it fires, use #[allow(...)] instead of #[expect(...)].

#[allow(clippy::needless_return)]

How to prevent it

• Re-check #[expect(...)] attributes when you refactor nearby code.
• Use #[expect] for lints you want to be told when they stop firing.
• Use #[allow] for permanent, unconditional suppression.

Frequently asked questions

Related guides

References

• Node.js documentation
• npm CLI documentation
• GitHub Actions documentation