Auto merge of #95436 - cjgillot:static-mut, r=oli-obk

Remember mutability in `DefKind::Static`.

This allows to compute the `BodyOwnerKind` from `DefKind` only, and
removes a direct dependency of some MIR queries onto HIR.

As a side effect, it also simplifies metadata, since we don't need 4
flavours of `EntryKind::*Static` any more.

compiler/rustc_middle/src/hir/map/mod.rs

@@ -228,7 +228,7 @@ impl<'hir> Map<'hir> {
         let hir_id = self.local_def_id_to_hir_id(local_def_id);
         let def_kind = match self.find(hir_id)? {
             Node::Item(item) => match item.kind {
-                ItemKind::Static(..) => DefKind::Static,
+                ItemKind::Static(_, mt, _) => DefKind::Static(mt),
                 ItemKind::Const(..) => DefKind::Const,
                 ItemKind::Fn(..) => DefKind::Fn,
                 ItemKind::Macro(_, macro_kind) => DefKind::Macro(macro_kind),
@@ -248,7 +248,7 @@ impl<'hir> Map<'hir> {
             },
             Node::ForeignItem(item) => match item.kind {
                 ForeignItemKind::Fn(..) => DefKind::Fn,
-                ForeignItemKind::Static(..) => DefKind::Static,
+                ForeignItemKind::Static(_, mt) => DefKind::Static(mt),
                 ForeignItemKind::Type => DefKind::ForeignTy,
             },
             Node::TraitItem(item) => match item.kind {
@@ -471,19 +471,15 @@ impl<'hir> Map<'hir> {
     /// Returns the `BodyOwnerKind` of this `LocalDefId`.
     ///
     /// Panics if `LocalDefId` does not have an associated body.
-    pub fn body_owner_kind(self, id: HirId) -> BodyOwnerKind {
-        match self.get(id) {
-            Node::Item(&Item { kind: ItemKind::Const(..), .. })
-            | Node::TraitItem(&TraitItem { kind: TraitItemKind::Const(..), .. })
-            | Node::ImplItem(&ImplItem { kind: ImplItemKind::Const(..), .. })
-            | Node::AnonConst(_) => BodyOwnerKind::Const,
-            Node::Ctor(..)
-            | Node::Item(&Item { kind: ItemKind::Fn(..), .. })
-            | Node::TraitItem(&TraitItem { kind: TraitItemKind::Fn(..), .. })
-            | Node::ImplItem(&ImplItem { kind: ImplItemKind::Fn(..), .. }) => BodyOwnerKind::Fn,
-            Node::Item(&Item { kind: ItemKind::Static(_, m, _), .. }) => BodyOwnerKind::Static(m),
-            Node::Expr(&Expr { kind: ExprKind::Closure(..), .. }) => BodyOwnerKind::Closure,
-            node => bug!("{:#?} is not a body node", node),
+    pub fn body_owner_kind(self, def_id: LocalDefId) -> BodyOwnerKind {
+        match self.tcx.def_kind(def_id) {
+            DefKind::Const | DefKind::AssocConst | DefKind::InlineConst | DefKind::AnonConst => {
+                BodyOwnerKind::Const
+            }
+            DefKind::Ctor(..) | DefKind::Fn | DefKind::AssocFn => BodyOwnerKind::Fn,
+            DefKind::Closure | DefKind::Generator => BodyOwnerKind::Closure,
+            DefKind::Static(mt) => BodyOwnerKind::Static(mt),
+            dk => bug!("{:?} is not a body node: {:?}", def_id, dk),
         }
     }
 
@@ -494,16 +490,17 @@ impl<'hir> Map<'hir> {
     /// This should only be used for determining the context of a body, a return
     /// value of `Some` does not always suggest that the owner of the body is `const`,
     /// just that it has to be checked as if it were.
-    pub fn body_const_context(self, did: LocalDefId) -> Option<ConstContext> {
-        let hir_id = self.local_def_id_to_hir_id(did);
-        let ccx = match self.body_owner_kind(hir_id) {
+    pub fn body_const_context(self, def_id: LocalDefId) -> Option<ConstContext> {
+        let ccx = match self.body_owner_kind(def_id) {
             BodyOwnerKind::Const => ConstContext::Const,
             BodyOwnerKind::Static(mt) => ConstContext::Static(mt),
 
-            BodyOwnerKind::Fn if self.tcx.is_constructor(did.to_def_id()) => return None,
-            BodyOwnerKind::Fn if self.tcx.is_const_fn_raw(did.to_def_id()) => ConstContext::ConstFn,
+            BodyOwnerKind::Fn if self.tcx.is_constructor(def_id.to_def_id()) => return None,
+            BodyOwnerKind::Fn if self.tcx.is_const_fn_raw(def_id.to_def_id()) => {
+                ConstContext::ConstFn
+            }
             BodyOwnerKind::Fn
-                if self.tcx.has_attr(did.to_def_id(), sym::default_method_body_is_const) =>
+                if self.tcx.has_attr(def_id.to_def_id(), sym::default_method_body_is_const) =>
             {
                 ConstContext::ConstFn
             }

compiler/rustc_middle/src/mir/pretty.rs

@@ -950,9 +950,8 @@ fn write_mir_sig(tcx: TyCtxt<'_>, body: &Body<'_>, w: &mut dyn Write) -> io::Res
     match (kind, body.source.promoted) {
         (_, Some(i)) => write!(w, "{:?} in ", i)?,
         (DefKind::Const | DefKind::AssocConst, _) => write!(w, "const ")?,
-        (DefKind::Static, _) => {
-            write!(w, "static {}", if tcx.is_mutable_static(def_id) { "mut " } else { "" })?
-        }
+        (DefKind::Static(hir::Mutability::Not), _) => write!(w, "static ")?,
+        (DefKind::Static(hir::Mutability::Mut), _) => write!(w, "static mut ")?,
         (_, _) if is_function => write!(w, "fn ")?,
         (DefKind::AnonConst | DefKind::InlineConst, _) => {} // things like anon const, not an item
         _ => bug!("Unexpected def kind {:?}", kind),

compiler/rustc_middle/src/query/mod.rs

@@ -586,12 +586,6 @@ rustc_queries! {
         separate_provide_extern
     }
 
-    /// Returns `Some(mutability)` if the node pointed to by `def_id` is a static item.
-    query static_mutability(def_id: DefId) -> Option<hir::Mutability> {
-        desc { |tcx| "looking up static mutability of `{}`", tcx.def_path_str(def_id) }
-        separate_provide_extern
-    }
-
     /// Returns `Some(generator_kind)` if the node pointed to by `def_id` is a generator.
     query generator_kind(def_id: DefId) -> Option<hir::GeneratorKind> {
         desc { |tcx| "looking up generator kind of `{}`", tcx.def_path_str(def_id) }

compiler/rustc_middle/src/ty/mod.rs

@@ -2147,7 +2147,7 @@ impl<'tcx> TyCtxt<'tcx> {
         match instance {
             ty::InstanceDef::Item(def) => match self.def_kind(def.did) {
                 DefKind::Const
-                | DefKind::Static
+                | DefKind::Static(..)
                 | DefKind::AssocConst
                 | DefKind::Ctor(..)
                 | DefKind::AnonConst

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -1188,7 +1188,7 @@ pub trait PrettyPrinter<'tcx>:
             }
             ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted: None }) => {
                 match self.tcx().def_kind(def.did) {
-                    DefKind::Static | DefKind::Const | DefKind::AssocConst => {
+                    DefKind::Static(..) | DefKind::Const | DefKind::AssocConst => {
                         p!(print_value_path(def.did, substs))
                     }
                     _ => {

compiler/rustc_middle/src/ty/util.rs

@@ -533,8 +533,14 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     /// Returns `true` if the node pointed to by `def_id` is a `static` item.
+    #[inline]
     pub fn is_static(self, def_id: DefId) -> bool {
-        self.static_mutability(def_id).is_some()
+        matches!(self.def_kind(def_id), DefKind::Static(_))
+    }
+
+    #[inline]
+    pub fn static_mutability(self, def_id: DefId) -> Option<hir::Mutability> {
+        if let DefKind::Static(mt) = self.def_kind(def_id) { Some(mt) } else { None }
     }
 
     /// Returns `true` if this is a `static` item with the `#[thread_local]` attribute.
@@ -543,6 +549,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     /// Returns `true` if the node pointed to by `def_id` is a mutable `static` item.
+    #[inline]
     pub fn is_mutable_static(self, def_id: DefId) -> bool {
         self.static_mutability(def_id) == Some(hir::Mutability::Mut)
     }