stability: Do not use buffer_lint after lowering to HIR

src/librustc/middle/stability.rs

@@ -485,7 +485,13 @@ pub fn provide(providers: &mut Providers<'_>) {
 }
 
 pub fn report_unstable(
-    sess: &Session, feature: Symbol, reason: Option<Symbol>, issue: u32, is_soft: bool, span: Span
+    sess: &Session,
+    feature: Symbol,
+    reason: Option<Symbol>,
+    issue: u32,
+    is_soft: bool,
+    span: Span,
+    soft_handler: impl FnOnce(&'static lint::Lint, Span, &str),
 ) {
     let msg = match reason {
         Some(r) => format!("use of unstable library feature '{}': {}", feature, r),
@@ -511,7 +517,7 @@ pub fn report_unstable(
     let fresh = sess.one_time_diagnostics.borrow_mut().insert(error_id);
     if fresh {
         if is_soft {
-            sess.buffer_lint(lint::builtin::SOFT_UNSTABLE, CRATE_NODE_ID, span, &msg);
+            soft_handler(lint::builtin::SOFT_UNSTABLE, span, &msg)
         } else {
             emit_feature_err(
                 &sess.parse_sess, feature, span, GateIssue::Library(Some(issue)), &msg
@@ -779,10 +785,12 @@ impl<'tcx> TyCtxt<'tcx> {
     /// Additionally, this function will also check if the item is deprecated. If so, and `id` is
     /// not `None`, a deprecated lint attached to `id` will be emitted.
     pub fn check_stability(self, def_id: DefId, id: Option<HirId>, span: Span) {
+        let soft_handler =
+            |lint, span, msg: &_| self.lint_hir(lint, id.unwrap_or(hir::CRATE_HIR_ID), span, msg);
         match self.eval_stability(def_id, id, span) {
             EvalResult::Allow => {}
             EvalResult::Deny { feature, reason, issue, is_soft } =>
-                report_unstable(self.sess, feature, reason, issue, is_soft, span),
+                report_unstable(self.sess, feature, reason, issue, is_soft, span, soft_handler),
             EvalResult::Unmarked => {
                 // The API could be uncallable for other reasons, for example when a private module
                 // was referenced.

src/librustc_resolve/macros.rs

@@ -796,7 +796,12 @@ impl<'a> Resolver<'a> {
             if let StabilityLevel::Unstable { reason, issue, is_soft } = stability.level {
                 let feature = stability.feature;
                 if !self.active_features.contains(&feature) && !span.allows_unstable(feature) {
-                    stability::report_unstable(self.session, feature, reason, issue, is_soft, span);
+                    let node_id = ast::CRATE_NODE_ID;
+                    let soft_handler =
+                        |lint, span, msg: &_| self.session.buffer_lint(lint, node_id, span, msg);
+                    stability::report_unstable(
+                        self.session, feature, reason, issue, is_soft, span, soft_handler
+                    );
                 }
             }
             if let Some(depr) = &stability.rustc_depr {

src/test/ui/feature-gates/bench.rs

@@ -1,5 +1,9 @@
+// edition:2018
+
 #[bench] //~ ERROR use of unstable library feature 'test'
          //~| WARN this was previously accepted
 fn bench() {}
 
+use bench as _; //~ ERROR use of unstable library feature 'test'
+                //~| WARN this was previously accepted
 fn main() {}

src/test/ui/feature-gates/bench.stderr

@@ -1,5 +1,5 @@
 error: use of unstable library feature 'test': `bench` is a part of custom test frameworks which are unstable
-  --> $DIR/bench.rs:1:3
+  --> $DIR/bench.rs:3:3
    |
 LL | #[bench]
    |   ^^^^^
@@ -8,5 +8,14 @@ LL | #[bench]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
 
-error: aborting due to previous error
+error: use of unstable library feature 'test': `bench` is a part of custom test frameworks which are unstable
+  --> $DIR/bench.rs:7:5
+   |
+LL | use bench as _;
+   |     ^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
+
+error: aborting due to 2 previous errors