Auto merge of #99520 - matthiaskrgr:rollup-05uuv5s, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #99212 (introduce `implied_by` in `#[unstable]` attribute)
 - #99352 (Use `typeck_results` to avoid duplicate `ast_ty_to_ty` call)
 - #99355 (better error for bad depth parameter on macro metavar expr)
 - #99480 (Diagnostic width span is not added when '0$' is used as width in format strings)
 - #99488 (compiletest: Allow using revisions with debuginfo tests.)
 - #99489 (rustdoc UI fixes)
 - #99508 (Avoid `Symbol` to `String` conversions)
 - #99510 (adapt assembly/static-relocation-model test for LLVM change)
 - #99516 (Use new tracking issue for proc_macro::tracked_*.)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

2 files changed, 11 insertions, 4 deletions

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 7a1695fc862..df13136dcce 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -2603,9 +2603,9 @@ fn show_candidates(
                 .skip(1)
                 .all(|(_, descr, _, _)| descr == descr_first)
             {
-                descr_first.to_string()
+                descr_first
             } else {
-                "item".to_string()
+                "item"
             };
             let plural_descr =
                 if descr.ends_with("s") { format!("{}es", descr) } else { format!("{}s", descr) };
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index 54dd15270a1..2b5eb12a8a8 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -796,9 +796,16 @@ impl<'a> Resolver<'a> {
     ) {
         let span = path.span;
         if let Some(stability) = &ext.stability {
-            if let StabilityLevel::Unstable { reason, issue, is_soft } = stability.level {
+            if let StabilityLevel::Unstable { reason, issue, is_soft, implied_by } = stability.level
+            {
                 let feature = stability.feature;
-                if !self.active_features.contains(&feature) && !span.allows_unstable(feature) {
+
+                let is_allowed = |feature| {
+                    self.active_features.contains(&feature) || span.allows_unstable(feature)
+                };
+                let allowed_by_implication =
+                    implied_by.map(|feature| is_allowed(feature)).unwrap_or(false);
+                if !is_allowed(feature) && !allowed_by_implication {
                     let lint_buffer = &mut self.lint_buffer;
                     let soft_handler =
                         |lint, span, msg: &_| lint_buffer.buffer_lint(lint, node_id, span, msg);