Auto merge of #60124 - petrochenkov:stanomut, r=eddyb

Remove mutability from `Def::Static`

Querify `TyCtxt::is_static`.
Use `Mutability` instead of bool in foreign statics in AST/HIR.

cc #60110
r? @eddyb

Author: bors

src/librustc/hir/def.rs

@@ -73,7 +73,7 @@ pub enum Def<Id = hir::HirId> {
     Fn(DefId),
     Const(DefId),
     ConstParam(DefId),
-    Static(DefId, bool /* is_mutbl */),
+    Static(DefId),
     /// `DefId` refers to the struct or enum variant's constructor.
     Ctor(DefId, CtorOf, CtorKind),
     SelfCtor(DefId /* impl */),  // `DefId` refers to the impl
@@ -291,7 +291,7 @@ impl<Id> Def<Id> {
     /// Return `Some(..)` with the `DefId` of this `Def` if it has a id, else `None`.
     pub fn opt_def_id(&self) -> Option<DefId> {
         match *self {
-            Def::Fn(id) | Def::Mod(id) | Def::Static(id, _) |
+            Def::Fn(id) | Def::Mod(id) | Def::Static(id) |
             Def::Variant(id) | Def::Ctor(id, ..) | Def::Enum(id) |
             Def::TyAlias(id) | Def::TraitAlias(id) |
             Def::AssociatedTy(id) | Def::TyParam(id) | Def::ConstParam(id) | Def::Struct(id) |
@@ -379,7 +379,7 @@ impl<Id> Def<Id> {
         match self {
             Def::Fn(id) => Def::Fn(id),
             Def::Mod(id) => Def::Mod(id),
-            Def::Static(id, is_mutbl) => Def::Static(id, is_mutbl),
+            Def::Static(id) => Def::Static(id),
             Def::Enum(id) => Def::Enum(id),
             Def::Variant(id) => Def::Variant(id),
             Def::Ctor(a, b, c) => Def::Ctor(a, b, c),

src/librustc/hir/lowering.rs

@@ -3742,7 +3742,7 @@ impl<'a> LoweringContext<'a> {
                 }
                 ForeignItemKind::Static(ref t, m) => {
                     hir::ForeignItemKind::Static(
-                        self.lower_ty(t, ImplTraitContext::disallowed()), m)
+                        self.lower_ty(t, ImplTraitContext::disallowed()), self.lower_mutability(m))
                 }
                 ForeignItemKind::Ty => hir::ForeignItemKind::Type,
                 ForeignItemKind::Macro(_) => panic!("shouldn't exist here"),

src/librustc/hir/map/mod.rs

@@ -322,7 +322,7 @@ impl<'hir> Map<'hir> {
                 let def_id = || self.local_def_id_from_hir_id(item.hir_id);
 
                 match item.node {
-                    ItemKind::Static(_, m, _) => Some(Def::Static(def_id(), m == MutMutable)),
+                    ItemKind::Static(..) => Some(Def::Static(def_id())),
                     ItemKind::Const(..) => Some(Def::Const(def_id())),
                     ItemKind::Fn(..) => Some(Def::Fn(def_id())),
                     ItemKind::Mod(..) => Some(Def::Mod(def_id())),
@@ -344,7 +344,7 @@ impl<'hir> Map<'hir> {
                 let def_id = self.local_def_id_from_hir_id(item.hir_id);
                 match item.node {
                     ForeignItemKind::Fn(..) => Some(Def::Fn(def_id)),
-                    ForeignItemKind::Static(_, m) => Some(Def::Static(def_id, m)),
+                    ForeignItemKind::Static(..) => Some(Def::Static(def_id)),
                     ForeignItemKind::Type => Some(Def::ForeignTy(def_id)),
                 }
             }

src/librustc/hir/mod.rs

@@ -2405,9 +2405,8 @@ pub struct ForeignItem {
 pub enum ForeignItemKind {
     /// A foreign function.
     Fn(P<FnDecl>, HirVec<Ident>, Generics),
-    /// A foreign static item (`static ext: u8`), with optional mutability
-    /// (the boolean is true when mutable).
-    Static(P<Ty>, bool),
+    /// A foreign static item (`static ext: u8`).
+    Static(P<Ty>, Mutability),
     /// A foreign type.
     Type,
 }

src/librustc/hir/print.rs

@@ -466,7 +466,7 @@ impl<'a> State<'a> {
             }
             hir::ForeignItemKind::Static(ref t, m) => {
                 self.head(visibility_qualified(&item.vis, "static"))?;
-                if m {
+                if m == hir::MutMutable {
                     self.word_space("mut")?;
                 }
                 self.print_ident(item.ident)?;

src/librustc/middle/mem_categorization.rs

@@ -705,7 +705,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                 Ok(self.cat_rvalue_node(hir_id, span, expr_ty))
             }
 
-            Def::Static(def_id, mutbl) => {
+            Def::Static(def_id) => {
                 // `#[thread_local]` statics may not outlive the current function, but
                 // they also cannot be moved out of.
                 let is_thread_local = self.tcx.get_attrs(def_id)[..]
@@ -723,7 +723,10 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                     hir_id,
                     span,
                     cat,
-                    mutbl: if mutbl { McDeclared } else { McImmutable},
+                    mutbl: match self.tcx.static_mutability(def_id).unwrap() {
+                        hir::MutImmutable => McImmutable,
+                        hir::MutMutable => McDeclared,
+                    },
                     ty:expr_ty,
                     note: NoteNone
                 })

src/librustc/query/mod.rs

@@ -238,6 +238,9 @@ rustc_queries! {
         /// True if this is a foreign item (i.e., linked via `extern { ... }`).
         query is_foreign_item(_: DefId) -> bool {}
 
+        /// Returns `Some(mutability)` if the node pointed to by `def_id` is a static item.
+        query static_mutability(_: DefId) -> Option<hir::Mutability> {}
+
         /// Get a map with the variance of every item; use `item_variance`
         /// instead.
         query crate_variances(_: CrateNum) -> Lrc<ty::CrateVariancesMap> {

src/librustc/ty/util.rs

@@ -1,9 +1,8 @@
 //! Miscellaneous type-system utilities that are too small to deserve their own modules.
 
-use crate::hir::def::Def;
+use crate::hir;
 use crate::hir::def_id::DefId;
 use crate::hir::map::DefPathData;
-use crate::hir::{self, Node};
 use crate::mir::interpret::{sign_extend, truncate};
 use crate::ich::NodeIdHashingMode;
 use crate::traits::{self, ObligationCause};
@@ -613,34 +612,14 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         })
     }
 
-    /// Returns `true` if the node pointed to by `def_id` is a static item, and its mutability.
-    pub fn is_static(&self, def_id: DefId) -> Option<hir::Mutability> {
-        if let Some(node) = self.hir().get_if_local(def_id) {
-            match node {
-                Node::Item(&hir::Item {
-                    node: hir::ItemKind::Static(_, mutbl, _), ..
-                }) => Some(mutbl),
-                Node::ForeignItem(&hir::ForeignItem {
-                    node: hir::ForeignItemKind::Static(_, is_mutbl), ..
-                }) =>
-                    Some(if is_mutbl {
-                        hir::Mutability::MutMutable
-                    } else {
-                        hir::Mutability::MutImmutable
-                    }),
-                _ => None
-            }
-        } else {
-            match self.describe_def(def_id) {
-                Some(Def::Static(_, is_mutbl)) =>
-                    Some(if is_mutbl {
-                        hir::Mutability::MutMutable
-                    } else {
-                        hir::Mutability::MutImmutable
-                    }),
-                _ => None
-            }
-        }
+    /// Returns `true` if the node pointed to by `def_id` is a `static` item.
+    pub fn is_static(&self, def_id: DefId) -> bool {
+        self.static_mutability(def_id).is_some()
+    }
+
+    /// Returns `true` if the node pointed to by `def_id` is a mutable `static` item.
+    pub fn is_mutable_static(&self, def_id: DefId) -> bool {
+        self.static_mutability(def_id) == Some(hir::MutMutable)
     }
 
     /// Expands the given impl trait type, stopping if the type is recursive.

src/librustc_codegen_llvm/common.rs

@@ -322,7 +322,7 @@ impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                         self.get_fn(fn_instance)
                     }
                     Some(AllocKind::Static(def_id)) => {
-                        assert!(self.tcx.is_static(def_id).is_some());
+                        assert!(self.tcx.is_static(def_id));
                         self.get_static(def_id)
                     }
                     None => bug!("missing allocation {:?}", ptr.alloc_id),

src/librustc_codegen_ssa/mono_item.rs

@@ -1,5 +1,4 @@
 use rustc::hir;
-use rustc::hir::def::Def;
 use rustc::mir::mono::{Linkage, Visibility};
 use rustc::ty::layout::HasTyCtxt;
 use std::fmt;
@@ -19,17 +18,7 @@ pub trait MonoItemExt<'a, 'tcx: 'a>: fmt::Debug + BaseMonoItemExt<'a, 'tcx> {
 
         match *self.as_mono_item() {
             MonoItem::Static(def_id) => {
-                let tcx = cx.tcx();
-                let is_mutable = match tcx.describe_def(def_id) {
-                    Some(Def::Static(_, is_mutable)) => is_mutable,
-                    Some(other) => {
-                        bug!("Expected Def::Static, found {:?}", other)
-                    }
-                    None => {
-                        bug!("Expected Def::Static for {:?}, found nothing", def_id)
-                    }
-                };
-                cx.codegen_static(def_id, is_mutable);
+                cx.codegen_static(def_id, cx.tcx().is_mutable_static(def_id));
             }
             MonoItem::GlobalAsm(hir_id) => {
                 let item = cx.tcx().hir().expect_item_by_hir_id(hir_id);