Handle safe safety keyword for extern block inner items

Author: spastorino

compiler/rustc_ast/src/ast.rs

@@ -2491,6 +2491,8 @@ pub enum Unsafe {
 pub enum Safety {
     /// `unsafe` an item is explicitly marked as `unsafe`.
     Unsafe(Span),
+    /// `safe` an item is explicitly marked as `safe`.
+    Safe(Span),
     /// Default means no value was provided, it will take a default value given the context in
     /// which is used.
     Default,
@@ -3142,6 +3144,7 @@ pub struct StaticItem {
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub struct StaticForeignItem {
     pub ty: P<Ty>,
+    pub safety: Safety,
     pub mutability: Mutability,
     pub expr: Option<P<Expr>>,
 }
@@ -3150,6 +3153,7 @@ impl From<StaticItem> for StaticForeignItem {
     fn from(static_item: StaticItem) -> StaticForeignItem {
         StaticForeignItem {
             ty: static_item.ty,
+            safety: Safety::Default,
             mutability: static_item.mutability,
             expr: static_item.expr,
         }

compiler/rustc_ast/src/mut_visit.rs

@@ -867,6 +867,7 @@ fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
 fn visit_fn_safety<T: MutVisitor>(safety: &mut Safety, vis: &mut T) {
     match safety {
         Safety::Unsafe(span) => vis.visit_span(span),
+        Safety::Safe(span) => vis.visit_span(span),
         Safety::Default => {}
     }
 }
@@ -1268,7 +1269,12 @@ pub fn noop_flat_map_item<K: NoopVisitItemKind>(
 impl NoopVisitItemKind for ForeignItemKind {
     fn noop_visit(&mut self, visitor: &mut impl MutVisitor) {
         match self {
-            ForeignItemKind::Static(box StaticForeignItem { ty, mutability: _, expr }) => {
+            ForeignItemKind::Static(box StaticForeignItem {
+                ty,
+                mutability: _,
+                expr,
+                safety: _,
+            }) => {
                 visitor.visit_ty(ty);
                 visit_opt(expr, |expr| visitor.visit_expr(expr));
             }