rustc_lint/
expect.rs

1use rustc_data_structures::fx::FxHashSet;
2use rustc_middle::lint::LintExpectation;
3use rustc_middle::query::Providers;
4use rustc_middle::ty::TyCtxt;
5use rustc_session::lint::LintExpectationId;
6use rustc_session::lint::builtin::UNFULFILLED_LINT_EXPECTATIONS;
7use rustc_span::Symbol;
8
9use crate::lints::{Expectation, ExpectationNote};
10
11pub(crate) fn provide(providers: &mut Providers) {
12    *providers = Providers { lint_expectations, check_expectations, ..*providers };
13}
14
15fn lint_expectations(tcx: TyCtxt<'_>, (): ()) -> Vec<(LintExpectationId, LintExpectation)> {
16    let krate = tcx.hir_crate_items(());
17
18    let mut expectations = Vec::new();
19
20    for owner in krate.owners() {
21        let lints = tcx.shallow_lint_levels_on(owner);
22        expectations.extend_from_slice(&lints.expectations);
23    }
24
25    expectations
26}
27
28fn check_expectations(tcx: TyCtxt<'_>, tool_filter: Option<Symbol>) {
29    let lint_expectations = tcx.lint_expectations(());
30    let fulfilled_expectations = tcx.dcx().steal_fulfilled_expectation_ids();
31
32    // Turn a `LintExpectationId` into a `(AttrId, lint_index)` pair.
33    let canonicalize_id = |expect_id: &LintExpectationId| {
34        match *expect_id {
35            LintExpectationId::Unstable { attr_id, lint_index: Some(lint_index) } => {
36                (attr_id, lint_index)
37            }
38            LintExpectationId::Stable { hir_id, attr_index, lint_index: Some(lint_index) } => {
39                // We are an `eval_always` query, so looking at the attribute's `AttrId` is ok.
40                let attr_id = tcx.hir_attrs(hir_id)[attr_index as usize].id();
41
42                (attr_id, lint_index)
43            }
44            _ => panic!("fulfilled expectations must have a lint index"),
45        }
46    };
47
48    let fulfilled_expectations: FxHashSet<_> =
49        fulfilled_expectations.iter().map(canonicalize_id).collect();
50
51    for (expect_id, expectation) in lint_expectations {
52        // This check will always be true, since `lint_expectations` only holds stable ids
53        let LintExpectationId::Stable { hir_id, .. } = expect_id else {
54            unreachable!("at this stage all `LintExpectationId`s are stable");
55        };
56
57        let expect_id = canonicalize_id(expect_id);
58
59        if !fulfilled_expectations.contains(&expect_id)
60            && tool_filter.is_none_or(|filter| expectation.lint_tool == Some(filter))
61        {
62            let rationale = expectation.reason.map(|rationale| ExpectationNote { rationale });
63            let note = expectation.is_unfulfilled_lint_expectations;
64            tcx.emit_node_span_lint(
65                UNFULFILLED_LINT_EXPECTATIONS,
66                *hir_id,
67                expectation.emission_span,
68                Expectation { rationale, note },
69            );
70        }
71    }
72}
rustc_lint/expect.rs

rustc_lint/
expect.rs
