Rollup merge of #70043 - mark-i-m:def-kind-more, r=eddyb

Add all remaining `DefKind`s.

r? @eddyb or @Centril

~~I'm not sure if this is what you were thinking of. There are also a few places where I'm not sure what the correct choice is because I don't fully understand the meaning of some variants.~~

~~In general, it feels a bit odd to add some of these as `DefKind`s (e.g. `Arm`) because they don't feel like definitions. Are there things that it makes sense not to add?~~

src/librustc_hir/def.rs

@@ -77,6 +77,18 @@ pub enum DefKind {
 
     // Macro namespace
     Macro(MacroKind),
+
+    // Not namespaced (or they are, but we don't treat them so)
+    ExternCrate,
+    Use,
+    ForeignMod,
+    AnonConst,
+    Field,
+    LifetimeParam,
+    GlobalAsm,
+    Impl,
+    Closure,
+    Generator,
 }
 
 impl DefKind {
@@ -113,6 +125,16 @@ impl DefKind {
             DefKind::TyParam => "type parameter",
             DefKind::ConstParam => "const parameter",
             DefKind::Macro(macro_kind) => macro_kind.descr(),
+            DefKind::LifetimeParam => "lifetime parameter",
+            DefKind::Use => "import",
+            DefKind::ForeignMod => "foreign module",
+            DefKind::AnonConst => "constant expression",
+            DefKind::Field => "field",
+            DefKind::Impl => "implementation",
+            DefKind::Closure => "closure",
+            DefKind::Generator => "generator",
+            DefKind::ExternCrate => "extern crate",
+            DefKind::GlobalAsm => "global assembly block",
         }
     }
 
@@ -124,7 +146,10 @@ impl DefKind {
             | DefKind::AssocOpaqueTy
             | DefKind::AssocFn
             | DefKind::Enum
-            | DefKind::OpaqueTy => "an",
+            | DefKind::OpaqueTy
+            | DefKind::Impl
+            | DefKind::Use
+            | DefKind::ExternCrate => "an",
             DefKind::Macro(macro_kind) => macro_kind.article(),
             _ => "a",
         }
@@ -155,6 +180,18 @@ impl DefKind {
             | DefKind::AssocConst => ns == Namespace::ValueNS,
 
             DefKind::Macro(..) => ns == Namespace::MacroNS,
+
+            // Not namespaced.
+            DefKind::AnonConst
+            | DefKind::Field
+            | DefKind::LifetimeParam
+            | DefKind::ExternCrate
+            | DefKind::Closure
+            | DefKind::Generator
+            | DefKind::Use
+            | DefKind::ForeignMod
+            | DefKind::GlobalAsm
+            | DefKind::Impl => false,
         }
     }
 }

src/librustc_hir/hir.rs

@@ -2452,27 +2452,6 @@ pub enum ItemKind<'hir> {
 }
 
 impl ItemKind<'_> {
-    pub fn descr(&self) -> &str {
-        match *self {
-            ItemKind::ExternCrate(..) => "extern crate",
-            ItemKind::Use(..) => "`use` import",
-            ItemKind::Static(..) => "static item",
-            ItemKind::Const(..) => "constant item",
-            ItemKind::Fn(..) => "function",
-            ItemKind::Mod(..) => "module",
-            ItemKind::ForeignMod(..) => "extern block",
-            ItemKind::GlobalAsm(..) => "global asm item",
-            ItemKind::TyAlias(..) => "type alias",
-            ItemKind::OpaqueTy(..) => "opaque type",
-            ItemKind::Enum(..) => "enum",
-            ItemKind::Struct(..) => "struct",
-            ItemKind::Union(..) => "union",
-            ItemKind::Trait(..) => "trait",
-            ItemKind::TraitAlias(..) => "trait alias",
-            ItemKind::Impl { .. } => "implementation",
-        }
-    }
-
     pub fn generics(&self) -> Option<&Generics<'_>> {
         Some(match *self {
             ItemKind::Fn(_, ref generics, _)
@@ -2551,16 +2530,6 @@ pub enum ForeignItemKind<'hir> {
     Type,
 }
 
-impl ForeignItemKind<'hir> {
-    pub fn descriptive_variant(&self) -> &str {
-        match *self {
-            ForeignItemKind::Fn(..) => "foreign function",
-            ForeignItemKind::Static(..) => "foreign static item",
-            ForeignItemKind::Type => "foreign type",
-        }
-    }
-}
-
 /// A variable captured by a closure.
 #[derive(Debug, Copy, Clone, RustcEncodable, RustcDecodable, HashStable_Generic)]
 pub struct Upvar {

src/librustc_infer/infer/error_reporting/need_type_info.rs

@@ -207,12 +207,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                         .get_opt_name()
                         .map(|parent_symbol| parent_symbol.to_string());
 
-                    let type_parent_desc = self
-                        .tcx
-                        .def_kind(parent_def_id)
-                        .map(|parent_def_kind| parent_def_kind.descr(parent_def_id));
-
-                    (parent_name, type_parent_desc)
+                    (parent_name, Some(self.tcx.def_kind(parent_def_id).descr(parent_def_id)))
                 } else {
                     (None, None)
                 };

src/librustc_metadata/rmeta/decoder.rs

@@ -562,8 +562,8 @@ impl MetadataBlob {
 }
 
 impl EntryKind {
-    fn def_kind(&self) -> Option<DefKind> {
-        Some(match *self {
+    fn def_kind(&self) -> DefKind {
+        match *self {
             EntryKind::Const(..) => DefKind::Const,
             EntryKind::AssocConst(..) => DefKind::AssocConst,
             EntryKind::ImmStatic
@@ -587,14 +587,13 @@ impl EntryKind {
             EntryKind::Enum(..) => DefKind::Enum,
             EntryKind::MacroDef(_) => DefKind::Macro(MacroKind::Bang),
             EntryKind::ForeignType => DefKind::ForeignTy,
-
-            EntryKind::ForeignMod
-            | EntryKind::GlobalAsm
-            | EntryKind::Impl(_)
-            | EntryKind::Field
-            | EntryKind::Generator(_)
-            | EntryKind::Closure => return None,
-        })
+            EntryKind::Impl(_) => DefKind::Impl,
+            EntryKind::Closure => DefKind::Closure,
+            EntryKind::ForeignMod => DefKind::ForeignMod,
+            EntryKind::GlobalAsm => DefKind::GlobalAsm,
+            EntryKind::Field => DefKind::Field,
+            EntryKind::Generator(_) => DefKind::Generator,
+        }
     }
 }
 
@@ -679,11 +678,11 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         }
     }
 
-    fn def_kind(&self, index: DefIndex) -> Option<DefKind> {
+    fn def_kind(&self, index: DefIndex) -> DefKind {
         if !self.is_proc_macro(index) {
             self.kind(index).def_kind()
         } else {
-            Some(DefKind::Macro(macro_kind(self.raw_proc_macro(index))))
+            DefKind::Macro(macro_kind(self.raw_proc_macro(index)))
         }
     }
 
@@ -1009,20 +1008,19 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                             .get(self, child_index)
                             .unwrap_or(Lazy::empty());
                         for child_index in child_children.decode((self, sess)) {
-                            if let Some(kind) = self.def_kind(child_index) {
-                                callback(Export {
-                                    res: Res::Def(kind, self.local_def_id(child_index)),
-                                    ident: self.item_ident(child_index, sess),
-                                    vis: self.get_visibility(child_index),
-                                    span: self
-                                        .root
-                                        .tables
-                                        .span
-                                        .get(self, child_index)
-                                        .unwrap()
-                                        .decode((self, sess)),
-                                });
-                            }
+                            let kind = self.def_kind(child_index);
+                            callback(Export {
+                                res: Res::Def(kind, self.local_def_id(child_index)),
+                                ident: self.item_ident(child_index, sess),
+                                vis: self.get_visibility(child_index),
+                                span: self
+                                    .root
+                                    .tables
+                                    .span
+                                    .get(self, child_index)
+                                    .unwrap()
+                                    .decode((self, sess)),
+                            });
                         }
                         continue;
                     }
@@ -1033,10 +1031,8 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
 
                 let def_key = self.def_key(child_index);
                 let span = self.get_span(child_index, sess);
-                if let (Some(kind), true) = (
-                    self.def_kind(child_index),
-                    def_key.disambiguated_data.data.get_opt_name().is_some(),
-                ) {
+                if def_key.disambiguated_data.data.get_opt_name().is_some() {
+                    let kind = self.def_kind(child_index);
                     let ident = self.item_ident(child_index, sess);
                     let vis = self.get_visibility(child_index);
                     let def_id = self.local_def_id(child_index);

src/librustc_middle/hir/map/mod.rs

@@ -6,7 +6,7 @@ use crate::ty::TyCtxt;
 use rustc_ast::ast::{self, Name, NodeId};
 use rustc_data_structures::svh::Svh;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPath, Definitions};
 use rustc_hir::intravisit;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
@@ -227,10 +227,14 @@ impl<'hir> Map<'hir> {
         self.tcx.definitions.opt_local_def_id_to_hir_id(def_id)
     }
 
-    pub fn def_kind(&self, hir_id: HirId) -> Option<DefKind> {
-        let node = self.find(hir_id)?;
+    pub fn def_kind(&self, local_def_id: LocalDefId) -> DefKind {
+        // FIXME(eddyb) support `find` on the crate root.
+        if local_def_id.to_def_id().index == CRATE_DEF_INDEX {
+            return DefKind::Mod;
+        }
 
-        Some(match node {
+        let hir_id = self.local_def_id_to_hir_id(local_def_id);
+        match self.get(hir_id) {
             Node::Item(item) => match item.kind {
                 ItemKind::Static(..) => DefKind::Static,
                 ItemKind::Const(..) => DefKind::Const,
@@ -243,11 +247,11 @@ impl<'hir> Map<'hir> {
                 ItemKind::Union(..) => DefKind::Union,
                 ItemKind::Trait(..) => DefKind::Trait,
                 ItemKind::TraitAlias(..) => DefKind::TraitAlias,
-                ItemKind::ExternCrate(_)
-                | ItemKind::Use(..)
-                | ItemKind::ForeignMod(..)
-                | ItemKind::GlobalAsm(..)
-                | ItemKind::Impl { .. } => return None,
+                ItemKind::ExternCrate(_) => DefKind::ExternCrate,
+                ItemKind::Use(..) => DefKind::Use,
+                ItemKind::ForeignMod(..) => DefKind::ForeignMod,
+                ItemKind::GlobalAsm(..) => DefKind::GlobalAsm,
+                ItemKind::Impl { .. } => DefKind::Impl,
             },
             Node::ForeignItem(item) => match item.kind {
                 ForeignItemKind::Fn(..) => DefKind::Fn,
@@ -268,7 +272,7 @@ impl<'hir> Map<'hir> {
             Node::Variant(_) => DefKind::Variant,
             Node::Ctor(variant_data) => {
                 // FIXME(eddyb) is this even possible, if we have a `Node::Ctor`?
-                variant_data.ctor_hir_id()?;
+                assert_ne!(variant_data.ctor_hir_id(), None);
 
                 let ctor_of = match self.find(self.get_parent_node(hir_id)) {
                     Some(Node::Item(..)) => def::CtorOf::Struct,
@@ -277,10 +281,20 @@ impl<'hir> Map<'hir> {
                 };
                 DefKind::Ctor(ctor_of, def::CtorKind::from_hir(variant_data))
             }
-            Node::AnonConst(_)
-            | Node::Field(_)
-            | Node::Expr(_)
-            | Node::Stmt(_)
+            Node::AnonConst(_) => DefKind::AnonConst,
+            Node::Field(_) => DefKind::Field,
+            Node::Expr(expr) => match expr.kind {
+                ExprKind::Closure(.., None) => DefKind::Closure,
+                ExprKind::Closure(.., Some(_)) => DefKind::Generator,
+                _ => bug!("def_kind: unsupported node: {}", self.node_to_string(hir_id)),
+            },
+            Node::MacroDef(_) => DefKind::Macro(MacroKind::Bang),
+            Node::GenericParam(param) => match param.kind {
+                GenericParamKind::Lifetime { .. } => DefKind::LifetimeParam,
+                GenericParamKind::Type { .. } => DefKind::TyParam,
+                GenericParamKind::Const { .. } => DefKind::ConstParam,
+            },
+            Node::Stmt(_)
             | Node::PathSegment(_)
             | Node::Ty(_)
             | Node::TraitRef(_)
@@ -292,14 +306,8 @@ impl<'hir> Map<'hir> {
             | Node::Lifetime(_)
             | Node::Visibility(_)
             | Node::Block(_)
-            | Node::Crate(_) => return None,
-            Node::MacroDef(_) => DefKind::Macro(MacroKind::Bang),
-            Node::GenericParam(param) => match param.kind {
-                GenericParamKind::Lifetime { .. } => return None,
-                GenericParamKind::Type { .. } => DefKind::TyParam,
-                GenericParamKind::Const { .. } => DefKind::ConstParam,
-            },
-        })
+            | Node::Crate(_) => bug!("def_kind: unsupported node: {}", self.node_to_string(hir_id)),
+        }
     }
 
     fn find_entry(&self, id: HirId) -> Option<Entry<'hir>> {
@@ -1082,6 +1090,5 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId) -> String {
 }
 
 pub fn provide(providers: &mut Providers<'_>) {
-    providers.def_kind =
-        |tcx, def_id| tcx.hir().def_kind(tcx.hir().as_local_hir_id(def_id.expect_local()));
+    providers.def_kind = |tcx, def_id| tcx.hir().def_kind(def_id.expect_local());
 }

src/librustc_middle/middle/stability.rs

@@ -246,7 +246,7 @@ pub enum EvalResult {
 fn skip_stability_check_due_to_privacy(tcx: TyCtxt<'_>, mut def_id: DefId) -> bool {
     // Check if `def_id` is a trait method.
     match tcx.def_kind(def_id) {
-        Some(DefKind::AssocFn) | Some(DefKind::AssocTy) | Some(DefKind::AssocConst) => {
+        DefKind::AssocFn | DefKind::AssocTy | DefKind::AssocConst => {
             if let ty::TraitContainer(trait_def_id) = tcx.associated_item(def_id).container {
                 // Trait methods do not declare visibility (even
                 // for visibility info in cstore). Use containing

src/librustc_middle/query/mod.rs

@@ -620,7 +620,7 @@ rustc_queries! {
             cache_on_disk_if { true }
         }
 
-        query def_kind(_: DefId) -> Option<DefKind> {}
+        query def_kind(_: DefId) -> DefKind {}
         query def_span(_: DefId) -> Span {
             // FIXME(mw): DefSpans are not really inputs since they are derived from
             // HIR. But at the moment HIR hashing still contains some hacks that allow

src/librustc_middle/ty/context.rs

@@ -48,7 +48,7 @@ use rustc_errors::ErrorReported;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId, LOCAL_CRATE};
-use rustc_hir::definitions::{DefPathData, DefPathHash, Definitions};
+use rustc_hir::definitions::{DefPathHash, Definitions};
 use rustc_hir::lang_items;
 use rustc_hir::lang_items::PanicLocationLangItem;
 use rustc_hir::{HirId, Node, TraitCandidate};
@@ -1492,21 +1492,13 @@ impl<'tcx> TyCtxt<'tcx> {
 
     /// Returns a displayable description and article for the given `def_id` (e.g. `("a", "struct")`).
     pub fn article_and_description(&self, def_id: DefId) -> (&'static str, &'static str) {
-        self.def_kind(def_id)
-            .map(|def_kind| (def_kind.article(), def_kind.descr(def_id)))
-            .unwrap_or_else(|| match self.def_key(def_id).disambiguated_data.data {
-                DefPathData::ClosureExpr => match self.generator_kind(def_id) {
-                    None => ("a", "closure"),
-                    Some(rustc_hir::GeneratorKind::Async(..)) => ("an", "async closure"),
-                    Some(rustc_hir::GeneratorKind::Gen) => ("a", "generator"),
-                },
-                DefPathData::LifetimeNs(..) => ("a", "lifetime"),
-                DefPathData::Impl => ("an", "implementation"),
-                DefPathData::TypeNs(..) | DefPathData::ValueNs(..) | DefPathData::MacroNs(..) => {
-                    unreachable!()
-                }
-                _ => bug!("article_and_description called on def_id {:?}", def_id),
-            })
+        match self.def_kind(def_id) {
+            DefKind::Generator => match self.generator_kind(def_id).unwrap() {
+                rustc_hir::GeneratorKind::Async(..) => ("an", "async closure"),
+                rustc_hir::GeneratorKind::Gen => ("a", "generator"),
+            },
+            def_kind => (def_kind.article(), def_kind.descr(def_id)),
+        }
     }
 }
 

src/librustc_middle/ty/mod.rs

@@ -2680,7 +2680,7 @@ impl<'tcx> TyCtxt<'tcx> {
             }
         } else {
             match self.def_kind(def_id) {
-                Some(DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy) => true,
+                DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy => true,
                 _ => false,
             }
         };

src/librustc_middle/ty/print/pretty.rs

@@ -888,7 +888,7 @@ pub trait PrettyPrinter<'tcx>:
                     p!(write("::{:?}", promoted));
                 } else {
                     match self.tcx().def_kind(did) {
-                        Some(DefKind::Static | DefKind::Const | DefKind::AssocConst) => {
+                        DefKind::Static | DefKind::Const | DefKind::AssocConst => {
                             p!(print_value_path(did, substs))
                         }
                         _ => {