New upstream version 1.61.0+dfsg1

[rustc.git] / compiler / rustc_lint / src / expect.rs

diff --git a/compiler/rustc_lint/src/expect.rs b/compiler/rustc_lint/src/expect.rs
new file mode 100644 (file)
index 0000000..74fef0b
--- /dev/null
+++ b/compiler/rustc_lint/src/expect.rs
@@ -0,0 +1,50 @@
+use crate::builtin;
+use rustc_hir::HirId;
+use rustc_middle::{lint::LintExpectation, ty::TyCtxt};
+use rustc_session::lint::LintExpectationId;
+use rustc_span::symbol::sym;
+
+pub fn check_expectations(tcx: TyCtxt<'_>) {
+    if !tcx.sess.features_untracked().enabled(sym::lint_reasons) {
+        return;
+    }
+
+    let fulfilled_expectations = tcx.sess.diagnostic().steal_fulfilled_expectation_ids();
+    let lint_expectations = &tcx.lint_levels(()).lint_expectations;
+
+    for (id, expectation) in lint_expectations {
+        if !fulfilled_expectations.contains(id) {
+            // This check will always be true, since `lint_expectations` only
+            // holds stable ids
+            if let LintExpectationId::Stable { hir_id, .. } = id {
+                emit_unfulfilled_expectation_lint(tcx, *hir_id, expectation);
+            } else {
+                unreachable!("at this stage all `LintExpectationId`s are stable");
+            }
+        }
+    }
+}
+
+fn emit_unfulfilled_expectation_lint(
+    tcx: TyCtxt<'_>,
+    hir_id: HirId,
+    expectation: &LintExpectation,
+) {
+    tcx.struct_span_lint_hir(
+        builtin::UNFULFILLED_LINT_EXPECTATIONS,
+        hir_id,
+        expectation.emission_span,
+        |diag| {
+            let mut diag = diag.build("this lint expectation is unfulfilled");
+            if let Some(rationale) = expectation.reason {
+                diag.note(&rationale.as_str());
+            }
+
+            if expectation.is_unfulfilled_lint_expectations {
+                diag.note("the `unfulfilled_lint_expectations` lint can't be expected and will always produce this message");
+            }
+
+            diag.emit();
+        },
+    );
+}