Auto merge of rust-lang#124524 - spastorino:make-foreign-static-use-s…

…truct, r=<try>

Add StaticForeignItem and use it on ForeignItemKind

This is in preparation for unsafe extern blocks that adds a safe variant for functions inside extern blocks.

r? `@oli-obk`
cc `@compiler-errors`

compiler/rustc_ast/src/ast.rs

@@ -3126,6 +3126,35 @@ pub struct StaticItem {
     pub expr: Option<P<Expr>>,
 }
 
+/// A static item in `extern` block.
+// This struct is identical to StaticItem for now but it's going to have a safety attribute.
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct StaticForeignItem {
+    pub ty: P<Ty>,
+    pub mutability: Mutability,
+    pub expr: Option<P<Expr>>,
+}
+
+impl From<StaticItem> for StaticForeignItem {
+    fn from(static_item: StaticItem) -> StaticForeignItem {
+        StaticForeignItem {
+            ty: static_item.ty,
+            mutability: static_item.mutability,
+            expr: static_item.expr,
+        }
+    }
+}
+
+impl From<StaticForeignItem> for StaticItem {
+    fn from(static_item: StaticForeignItem) -> StaticItem {
+        StaticItem {
+            ty: static_item.ty,
+            mutability: static_item.mutability,
+            expr: static_item.expr,
+        }
+    }
+}
+
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub struct ConstItem {
     pub defaultness: Defaultness,
@@ -3329,7 +3358,7 @@ impl TryFrom<ItemKind> for AssocItemKind {
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub enum ForeignItemKind {
     /// A foreign static item (`static FOO: u8`).
-    Static(P<Ty>, Mutability, Option<P<Expr>>),
+    Static(Box<StaticForeignItem>),
     /// An foreign function.
     Fn(Box<Fn>),
     /// An foreign type.
@@ -3341,8 +3370,8 @@ pub enum ForeignItemKind {
 impl From<ForeignItemKind> for ItemKind {
     fn from(foreign_item_kind: ForeignItemKind) -> ItemKind {
         match foreign_item_kind {
-            ForeignItemKind::Static(a, b, c) => {
-                ItemKind::Static(StaticItem { ty: a, mutability: b, expr: c }.into())
+            ForeignItemKind::Static(box static_foreign_item) => {
+                ItemKind::Static(Box::new(static_foreign_item.into()))
             }
             ForeignItemKind::Fn(fn_kind) => ItemKind::Fn(fn_kind),
             ForeignItemKind::TyAlias(ty_alias_kind) => ItemKind::TyAlias(ty_alias_kind),
@@ -3356,8 +3385,8 @@ impl TryFrom<ItemKind> for ForeignItemKind {
 
     fn try_from(item_kind: ItemKind) -> Result<ForeignItemKind, ItemKind> {
         Ok(match item_kind {
-            ItemKind::Static(box StaticItem { ty: a, mutability: b, expr: c }) => {
-                ForeignItemKind::Static(a, b, c)
+            ItemKind::Static(box static_item) => {
+                ForeignItemKind::Static(Box::new(static_item.into()))
             }
             ItemKind::Fn(fn_kind) => ForeignItemKind::Fn(fn_kind),
             ItemKind::TyAlias(ty_alias_kind) => ForeignItemKind::TyAlias(ty_alias_kind),
@@ -3382,8 +3411,8 @@ mod size_asserts {
     static_assert_size!(Expr, 72);
     static_assert_size!(ExprKind, 40);
     static_assert_size!(Fn, 160);
-    static_assert_size!(ForeignItem, 96);
-    static_assert_size!(ForeignItemKind, 24);
+    static_assert_size!(ForeignItem, 88);
+    static_assert_size!(ForeignItemKind, 16);
     static_assert_size!(GenericArg, 24);
     static_assert_size!(GenericBound, 88);
     static_assert_size!(Generics, 40);

compiler/rustc_ast/src/mut_visit.rs

@@ -1261,7 +1261,7 @@ 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(ty, _, expr) => {
+            ForeignItemKind::Static(box StaticForeignItem { ty, mutability: _, expr }) => {
                 visitor.visit_ty(ty);
                 visit_opt(expr, |expr| visitor.visit_expr(expr));
             }

compiler/rustc_ast/src/visit.rs

@@ -642,7 +642,7 @@ impl WalkItemKind for ForeignItemKind {
     ) -> V::Result {
         let &Item { id, span, ident, ref vis, .. } = item;
         match self {
-            ForeignItemKind::Static(ty, _, expr) => {
+            ForeignItemKind::Static(box StaticForeignItem { ty, mutability: _, expr }) => {
                 try_visit!(visitor.visit_ty(ty));
                 visit_opt!(visitor, visit_expr, expr);
             }

compiler/rustc_ast_lowering/src/item.rs

@@ -662,10 +662,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
                     hir::ForeignItemKind::Fn(fn_dec, fn_args, generics)
                 }
-                ForeignItemKind::Static(t, m, _) => {
-                    let ty =
-                        self.lower_ty(t, ImplTraitContext::Disallowed(ImplTraitPosition::StaticTy));
-                    hir::ForeignItemKind::Static(ty, *m)
+                ForeignItemKind::Static(box StaticForeignItem { ty, mutability, expr: _ }) => {
+                    let ty = self
+                        .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::StaticTy));
+                    hir::ForeignItemKind::Static(ty, *mutability)
                 }
                 ForeignItemKind::TyAlias(..) => hir::ForeignItemKind::Type,
                 ForeignItemKind::MacCall(_) => panic!("macro shouldn't exist here"),

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -1185,8 +1185,8 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 self.check_foreign_ty_genericless(generics, where_clauses);
                 self.check_foreign_item_ascii_only(fi.ident);
             }
-            ForeignItemKind::Static(_, _, body) => {
-                self.check_foreign_kind_bodyless(fi.ident, "static", body.as_ref().map(|b| b.span));
+            ForeignItemKind::Static(box StaticForeignItem { ty: _, mutability: _, expr }) => {
+                self.check_foreign_kind_bodyless(fi.ident, "static", expr.as_ref().map(|b| b.span));
                 self.check_foreign_item_ascii_only(fi.ident);
             }
             ForeignItemKind::MacCall(..) => {}

compiler/rustc_ast_pretty/src/pprust/state/item.rs

@@ -30,15 +30,17 @@ impl<'a> State<'a> {
             ast::ForeignItemKind::Fn(box ast::Fn { defaultness, sig, generics, body }) => {
                 self.print_fn_full(sig, ident, generics, vis, *defaultness, body.as_deref(), attrs);
             }
-            ast::ForeignItemKind::Static(ty, mutbl, body) => self.print_item_const(
-                ident,
-                Some(*mutbl),
-                &ast::Generics::default(),
-                ty,
-                body.as_deref(),
-                vis,
-                ast::Defaultness::Final,
-            ),
+            ast::ForeignItemKind::Static(box ast::StaticForeignItem { ty, mutability, expr }) => {
+                self.print_item_const(
+                    ident,
+                    Some(*mutability),
+                    &ast::Generics::default(),
+                    ty,
+                    expr.as_deref(),
+                    vis,
+                    ast::Defaultness::Final,
+                )
+            }
             ast::ForeignItemKind::TyAlias(box ast::TyAlias {
                 defaultness,
                 generics,

compiler/rustc_parse/src/parser/item.rs

@@ -1191,7 +1191,11 @@ impl<'a> Parser<'a> {
                                 ident_span: ident.span,
                                 const_span,
                             });
-                            ForeignItemKind::Static(ty, Mutability::Not, expr)
+                            ForeignItemKind::Static(Box::new(StaticForeignItem {
+                                ty,
+                                mutability: Mutability::Not,
+                                expr,
+                            }))
                         }
                         _ => return self.error_bad_item_kind(span, &kind, "`extern` blocks"),
                     },

compiler/rustc_resolve/src/def_collector.rs

@@ -209,7 +209,7 @@ impl<'a, 'b, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'b, 'tcx> {
 
     fn visit_foreign_item(&mut self, fi: &'a ForeignItem) {
         let def_kind = match fi.kind {
-            ForeignItemKind::Static(_, mutability, _) => {
+            ForeignItemKind::Static(box StaticForeignItem { ty: _, mutability, expr: _ }) => {
                 DefKind::Static { mutability, nested: false }
             }
             ForeignItemKind::Fn(_) => DefKind::Fn,