Auto merge of #134353 - oli-obk:safe-target-feature-unsafe-by-default, r=wesleywiser

Treat safe target_feature functions as unsafe by default [less invasive variant]

This unblocks
* #134090

As I stated in https://github.com/rust-lang/rust/pull/134090#issuecomment-2541332415 I think the previous impl was too easy to get wrong, as by default it treated safe target feature functions as safe and had to add additional checks for when they weren't. Now the logic is inverted. By default they are unsafe and you have to explicitly handle safe target feature functions.

This is the less (imo) invasive variant of #134317, as it doesn't require changing the Safety enum, so it only affects FnDefs and nothing else, as it should.

1 files changed, 4 insertions, 3 deletions

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 7324d3fe786..c4aeaf478bd 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -5019,12 +5019,13 @@ struct ItemInfoCollector<'a, 'ra, 'tcx> {
 }
 
 impl ItemInfoCollector<'_, '_, '_> {
-    fn collect_fn_info(&mut self, sig: &FnSig, id: NodeId) {
+    fn collect_fn_info(&mut self, sig: &FnSig, id: NodeId, attrs: &[Attribute]) {
         let sig = DelegationFnSig {
             header: sig.header,
             param_count: sig.decl.inputs.len(),
             has_self: sig.decl.has_self(),
             c_variadic: sig.decl.c_variadic(),
+            target_feature: attrs.iter().any(|attr| attr.has_name(sym::target_feature)),
         };
         self.r.delegation_fn_sigs.insert(self.r.local_def_id(id), sig);
     }
@@ -5043,7 +5044,7 @@ impl<'ast> Visitor<'ast> for ItemInfoCollector<'_, '_, '_> {
             | ItemKind::Trait(box Trait { ref generics, .. })
             | ItemKind::TraitAlias(ref generics, _) => {
                 if let ItemKind::Fn(box Fn { ref sig, .. }) = &item.kind {
-                    self.collect_fn_info(sig, item.id);
+                    self.collect_fn_info(sig, item.id, &item.attrs);
                 }
 
                 let def_id = self.r.local_def_id(item.id);
@@ -5076,7 +5077,7 @@ impl<'ast> Visitor<'ast> for ItemInfoCollector<'_, '_, '_> {
 
     fn visit_assoc_item(&mut self, item: &'ast AssocItem, ctxt: AssocCtxt) {
         if let AssocItemKind::Fn(box Fn { ref sig, .. }) = &item.kind {
-            self.collect_fn_info(sig, item.id);
+            self.collect_fn_info(sig, item.id, &item.attrs);
         }
         visit::walk_assoc_item(self, item, ctxt);
     }