compiler/rustc_lint/src/expect.rs

   1 use crate::builtin;
   2 use rustc_data_structures::fx::FxHashMap;
   3 use rustc_middle::lint::struct_lint_level;
   4 use rustc_middle::{lint::LintExpectation, ty::TyCtxt};
   5 use rustc_session::lint::LintExpectationId;
   6 use rustc_span::symbol::sym;
   7 use rustc_span::MultiSpan;
   8
   9 pub fn check_expectations(tcx: TyCtxt<'_>) {
  10     if !tcx.sess.features_untracked().enabled(sym::lint_reasons) {
  11         return;
  12     }
  13
  14     let fulfilled_expectations = tcx.sess.diagnostic().steal_fulfilled_expectation_ids();
  15     let lint_expectations: &FxHashMap<LintExpectationId, LintExpectation> =
  16         &tcx.lint_levels(()).lint_expectations;
  17
  18     for (id, expectation) in lint_expectations {
  19         if fulfilled_expectations.contains(id) {
  20             continue;
  21         }
  22
  23         emit_unfulfilled_expectation_lint(tcx, expectation);
  24     }
  25 }
  26
  27 fn emit_unfulfilled_expectation_lint(tcx: TyCtxt<'_>, expectation: &LintExpectation) {
  28     // FIXME: The current implementation doesn't cover cases where the
  29     // `unfulfilled_lint_expectations` is actually expected by another lint
  30     // expectation. This can be added here as we have the lint level of this
  31     // expectation, and we can also mark the lint expectation it would fulfill
  32     // as such. This is currently not implemented to get some early feedback
  33     // before diving deeper into this.
  34     struct_lint_level(
  35         tcx.sess,
  36         builtin::UNFULFILLED_LINT_EXPECTATIONS,
  37         expectation.emission_level,
  38         expectation.emission_level_source,
  39         Some(MultiSpan::from_span(expectation.emission_span)),
  40         |diag| {
  41             let mut diag = diag.build("this lint expectation is unfulfilled");
  42             if let Some(rationale) = expectation.reason {
  43                 diag.note(&rationale.as_str());
  44             }
  45             diag.emit();
  46         },
  47     );
  48 }