compiler/rustc_lint/src/expect.rs

   1 use crate::builtin;
   2 use rustc_errors::fluent;
   3 use rustc_hir::HirId;
   4 use rustc_middle::ty::query::Providers;
   5 use rustc_middle::{lint::LintExpectation, ty::TyCtxt};
   6 use rustc_session::lint::LintExpectationId;
   7 use rustc_span::symbol::sym;
   8 use rustc_span::Symbol;
   9
  10 pub(crate) fn provide(providers: &mut Providers) {
  11     *providers = Providers { check_expectations, ..*providers };
  12 }
  13
  14 fn check_expectations(tcx: TyCtxt<'_>, tool_filter: Option<Symbol>) {
  15     if !tcx.sess.features_untracked().enabled(sym::lint_reasons) {
  16         return;
  17     }
  18
  19     let lint_expectations = tcx.lint_expectations(());
  20     let fulfilled_expectations = tcx.sess.diagnostic().steal_fulfilled_expectation_ids();
  21
  22     tracing::debug!(?lint_expectations, ?fulfilled_expectations);
  23
  24     for (id, expectation) in lint_expectations {
  25         // This check will always be true, since `lint_expectations` only
  26         // holds stable ids
  27         if let LintExpectationId::Stable { hir_id, .. } = id {
  28             if !fulfilled_expectations.contains(&id)
  29                 && tool_filter.map_or(true, |filter| expectation.lint_tool == Some(filter))
  30             {
  31                 emit_unfulfilled_expectation_lint(tcx, *hir_id, expectation);
  32             }
  33         } else {
  34             unreachable!("at this stage all `LintExpectationId`s are stable");
  35         }
  36     }
  37 }
  38
  39 fn emit_unfulfilled_expectation_lint(
  40     tcx: TyCtxt<'_>,
  41     hir_id: HirId,
  42     expectation: &LintExpectation,
  43 ) {
  44     tcx.struct_span_lint_hir(
  45         builtin::UNFULFILLED_LINT_EXPECTATIONS,
  46         hir_id,
  47         expectation.emission_span,
  48         fluent::lint_expectation,
  49         |lint| {
  50             if let Some(rationale) = expectation.reason {
  51                 lint.note(rationale.as_str());
  52             }
  53
  54             if expectation.is_unfulfilled_lint_expectations {
  55                 lint.note(fluent::note);
  56             }
  57
  58             lint
  59         },
  60     );
  61 }