compiler/rustc_lint/src/expect.rs

   1 use crate::builtin;
   2 use rustc_hir::HirId;
   3 use rustc_middle::{lint::LintExpectation, ty::TyCtxt};
   4 use rustc_session::lint::LintExpectationId;
   5 use rustc_span::symbol::sym;
   6
   7 pub fn check_expectations(tcx: TyCtxt<'_>) {
   8     if !tcx.sess.features_untracked().enabled(sym::lint_reasons) {
   9         return;
  10     }
  11
  12     let fulfilled_expectations = tcx.sess.diagnostic().steal_fulfilled_expectation_ids();
  13     let lint_expectations = &tcx.lint_levels(()).lint_expectations;
  14
  15     for (id, expectation) in lint_expectations {
  16         if !fulfilled_expectations.contains(id) {
  17             // This check will always be true, since `lint_expectations` only
  18             // holds stable ids
  19             if let LintExpectationId::Stable { hir_id, .. } = id {
  20                 emit_unfulfilled_expectation_lint(tcx, *hir_id, expectation);
  21             } else {
  22                 unreachable!("at this stage all `LintExpectationId`s are stable");
  23             }
  24         }
  25     }
  26 }
  27
  28 fn emit_unfulfilled_expectation_lint(
  29     tcx: TyCtxt<'_>,
  30     hir_id: HirId,
  31     expectation: &LintExpectation,
  32 ) {
  33     tcx.struct_span_lint_hir(
  34         builtin::UNFULFILLED_LINT_EXPECTATIONS,
  35         hir_id,
  36         expectation.emission_span,
  37         |diag| {
  38             let mut diag = diag.build("this lint expectation is unfulfilled");
  39             if let Some(rationale) = expectation.reason {
  40                 diag.note(&rationale.as_str());
  41             }
  42
  43             if expectation.is_unfulfilled_lint_expectations {
  44                 diag.note("the `unfulfilled_lint_expectations` lint can't be expected and will always produce this message");
  45             }
  46
  47             diag.emit();
  48         },
  49     );
  50 }