Fix #[rustc_deprecated_safe_2024]

It should be considered by the edition of the caller, not the callee.

Technically we still don't do it correctly - we need the span of the method name (if it comes from a macro), but we don't keep it and this is good enough for now.

crates/hir-def/src/data.rs

@@ -95,10 +95,10 @@ impl FunctionData {
             .map(Box::new);
         let rustc_allow_incoherent_impl = attrs.by_key(&sym::rustc_allow_incoherent_impl).exists();
         if flags.contains(FnFlags::HAS_UNSAFE_KW)
-            && !crate_graph[krate].edition.at_least_2024()
             && attrs.by_key(&sym::rustc_deprecated_safe_2024).exists()
         {
             flags.remove(FnFlags::HAS_UNSAFE_KW);
+            flags.insert(FnFlags::DEPRECATED_SAFE_2024);
         }
 
         if attrs.by_key(&sym::target_feature).exists() {
@@ -152,6 +152,10 @@ impl FunctionData {
         self.flags.contains(FnFlags::HAS_UNSAFE_KW)
     }
 
+    pub fn is_deprecated_safe_2024(&self) -> bool {
+        self.flags.contains(FnFlags::DEPRECATED_SAFE_2024)
+    }
+
     pub fn is_safe(&self) -> bool {
         self.flags.contains(FnFlags::HAS_SAFE_KW)
     }

crates/hir-def/src/expr_store/lower.rs

@@ -2238,17 +2238,27 @@ impl ExprCollector<'_> {
         let unsafe_arg_new = self.alloc_expr_desugared(Expr::Path(unsafe_arg_new));
         let unsafe_arg_new =
             self.alloc_expr_desugared(Expr::Call { callee: unsafe_arg_new, args: Box::default() });
-        let unsafe_arg_new = self.alloc_expr_desugared(Expr::Unsafe {
+        let mut unsafe_arg_new = self.alloc_expr_desugared(Expr::Unsafe {
             id: None,
-            // We collect the unused expressions here so that we still infer them instead of
-            // dropping them out of the expression tree
-            statements: fmt
-                .orphans
-                .into_iter()
-                .map(|expr| Statement::Expr { expr, has_semi: true })
-                .collect(),
+            statements: Box::new([]),
             tail: Some(unsafe_arg_new),
         });
+        if !fmt.orphans.is_empty() {
+            unsafe_arg_new = self.alloc_expr_desugared(Expr::Block {
+                id: None,
+                // We collect the unused expressions here so that we still infer them instead of
+                // dropping them out of the expression tree. We cannot store them in the `Unsafe`
+                // block because then unsafe blocks within them will get a false "unused unsafe"
+                // diagnostic (rustc has a notion of builtin unsafe blocks, but we don't).
+                statements: fmt
+                    .orphans
+                    .into_iter()
+                    .map(|expr| Statement::Expr { expr, has_semi: true })
+                    .collect(),
+                tail: Some(unsafe_arg_new),
+                label: None,
+            });
+        }
 
         let idx = self.alloc_expr(
             Expr::Call {

crates/hir-def/src/item_tree.rs

@@ -951,6 +951,7 @@ bitflags::bitflags! {
         /// only very few functions with it. So we only encode its existence here, and lookup
         /// it if needed.
         const HAS_TARGET_FEATURE = 1 << 8;
+        const DEPRECATED_SAFE_2024 = 1 << 9;
     }
 }