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 fulfilled_expectations = tcx.sess.diagnostic().steal_fulfilled_expectation_ids();
  20     let lint_expectations = &tcx.lint_levels(()).lint_expectations;
  21
  22     for (id, expectation) in lint_expectations {
  23         // This check will always be true, since `lint_expectations` only
  24         // holds stable ids
  25         if let LintExpectationId::Stable { hir_id, .. } = id {
  26             if !fulfilled_expectations.contains(&id)
  27                 && tool_filter.map_or(true, |filter| expectation.lint_tool == Some(filter))
  28             {
  29                 emit_unfulfilled_expectation_lint(tcx, *hir_id, expectation);
  30             }
  31         } else {
  32             unreachable!("at this stage all `LintExpectationId`s are stable");
  33         }
  34     }
  35 }
  36
  37 fn emit_unfulfilled_expectation_lint(
  38     tcx: TyCtxt<'_>,
  39     hir_id: HirId,
  40     expectation: &LintExpectation,
  41 ) {
  42     tcx.struct_span_lint_hir(
  43         builtin::UNFULFILLED_LINT_EXPECTATIONS,
  44         hir_id,
  45         expectation.emission_span,
  46         |diag| {
  47             let mut diag = diag.build(fluent::lint::expectation);
  48             if let Some(rationale) = expectation.reason {
  49                 diag.note(rationale.as_str());
  50             }
  51
  52             if expectation.is_unfulfilled_lint_expectations {
  53                 diag.note(fluent::lint::note);
  54             }
  55
  56             diag.emit();
  57         },
  58     );
  59 }