Rollup of 7 pull requests

compiler/rustc_ast_lowering/src/expr.rs

@@ -13,7 +13,7 @@ use rustc_middle::span_bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::errors::report_lit_error;
 use rustc_span::source_map::{Spanned, respan};
-use rustc_span::{DUMMY_SP, DesugaringKind, Ident, Span, Symbol, kw, sym};
+use rustc_span::{DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
 use thin_vec::{ThinVec, thin_vec};
 use visit::{Visitor, walk_expr};
 
@@ -483,7 +483,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             if legacy_args_idx.contains(&idx) {
                 let parent_def_id = self.current_hir_id_owner.def_id;
                 let node_id = self.next_node_id();
-                self.create_def(parent_def_id, node_id, kw::Empty, DefKind::AnonConst, f.span);
+                self.create_def(parent_def_id, node_id, None, DefKind::AnonConst, f.span);
                 let mut visitor = WillCreateDefIdsVisitor {};
                 let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
                     AstP(Expr {

compiler/rustc_ast_lowering/src/lib.rs

@@ -494,7 +494,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         &mut self,
         parent: LocalDefId,
         node_id: ast::NodeId,
-        name: Symbol,
+        name: Option<Symbol>,
         def_kind: DefKind,
         span: Span,
     ) -> LocalDefId {
@@ -774,7 +774,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 let _def_id = self.create_def(
                     self.current_hir_id_owner.def_id,
                     param,
-                    kw::UnderscoreLifetime,
+                    Some(kw::UnderscoreLifetime),
                     DefKind::LifetimeParam,
                     ident.span,
                 );
@@ -2089,8 +2089,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             // We're lowering a const argument that was originally thought to be a type argument,
             // so the def collector didn't create the def ahead of time. That's why we have to do
             // it here.
-            let def_id =
-                self.create_def(parent_def_id, node_id, kw::Empty, DefKind::AnonConst, span);
+            let def_id = self.create_def(parent_def_id, node_id, None, DefKind::AnonConst, span);
             let hir_id = self.lower_node_id(node_id);
 
             let path_expr = Expr {

compiler/rustc_const_eval/src/interpret/intern.rs

@@ -104,7 +104,7 @@ fn intern_as_new_static<'tcx>(
 ) {
     let feed = tcx.create_def(
         static_id,
-        sym::nested,
+        Some(sym::nested),
         DefKind::Static { safety: hir::Safety::Safe, mutability: alloc.0.mutability, nested: true },
     );
     tcx.set_nested_alloc_id_static(alloc_id, feed.def_id());

compiler/rustc_errors/src/lib.rs

@@ -14,6 +14,7 @@
 #![feature(associated_type_defaults)]
 #![feature(box_into_inner)]
 #![feature(box_patterns)]
+#![feature(default_field_values)]
 #![feature(error_reporter)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]

compiler/rustc_errors/src/markdown/parse.rs

@@ -40,11 +40,13 @@ type ParseResult<'a> = Option<Parsed<'a>>;
 
 /// Parsing context
 #[derive(Clone, Copy, Debug, PartialEq)]
+// The default values are the most common setting for non top-level parsing: not top block, not at
+// line start (yes leading whitespace, not escaped).
 struct Context {
     /// If true, we are at a the topmost level (not recursing a nested tt)
-    top_block: bool,
+    top_block: bool = false,
     /// Previous character
-    prev: Prev,
+    prev: Prev = Prev::Whitespace,
 }
 
 /// Character class preceding this one
@@ -57,14 +59,6 @@ enum Prev {
     Any,
 }
 
-impl Default for Context {
-    /// Most common setting for non top-level parsing: not top block, not at
-    /// line start (yes leading whitespace, not escaped)
-    fn default() -> Self {
-        Self { top_block: false, prev: Prev::Whitespace }
-    }
-}
-
 /// Flags to simple parser function
 #[derive(Clone, Copy, Debug, PartialEq)]
 enum ParseOpt {
@@ -248,7 +242,7 @@ fn parse_heading(buf: &[u8]) -> ParseResult<'_> {
     }
 
     let (txt, rest) = parse_to_newline(&buf[1..]);
-    let ctx = Context { top_block: false, prev: Prev::Whitespace };
+    let ctx = Context { .. };
     let stream = parse_recursive(txt, ctx);
 
     Some((MdTree::Heading(level.try_into().unwrap(), stream), rest))
@@ -257,7 +251,7 @@ fn parse_heading(buf: &[u8]) -> ParseResult<'_> {
 /// Bulleted list
 fn parse_unordered_li(buf: &[u8]) -> Parsed<'_> {
     let (txt, rest) = get_indented_section(&buf[2..]);
-    let ctx = Context { top_block: false, prev: Prev::Whitespace };
+    let ctx = Context { .. };
     let stream = parse_recursive(trim_ascii_start(txt), ctx);
     (MdTree::UnorderedListItem(stream), rest)
 }
@@ -266,7 +260,7 @@ fn parse_unordered_li(buf: &[u8]) -> Parsed<'_> {
 fn parse_ordered_li(buf: &[u8]) -> Parsed<'_> {
     let (num, pos) = ord_list_start(buf).unwrap(); // success tested in caller
     let (txt, rest) = get_indented_section(&buf[pos..]);
-    let ctx = Context { top_block: false, prev: Prev::Whitespace };
+    let ctx = Context { .. };
     let stream = parse_recursive(trim_ascii_start(txt), ctx);
     (MdTree::OrderedListItem(num, stream), rest)
 }

compiler/rustc_hir/src/def.rs

@@ -253,7 +253,9 @@ impl DefKind {
         }
     }
 
-    pub fn def_path_data(self, name: Symbol) -> DefPathData {
+    // Some `DefKind`s require a name, some don't. Panics if one is needed but
+    // not provided. (`AssocTy` is an exception, see below.)
+    pub fn def_path_data(self, name: Option<Symbol>) -> DefPathData {
         match self {
             DefKind::Mod
             | DefKind::Struct
@@ -264,9 +266,13 @@ impl DefKind {
             | DefKind::TyAlias
             | DefKind::ForeignTy
             | DefKind::TraitAlias
-            | DefKind::AssocTy
             | DefKind::TyParam
-            | DefKind::ExternCrate => DefPathData::TypeNs(name),
+            | DefKind::ExternCrate => DefPathData::TypeNs(Some(name.unwrap())),
+
+            // An associated type names will be missing for an RPITIT. It will
+            // later be given a name with `synthetic` in it, if necessary.
+            DefKind::AssocTy => DefPathData::TypeNs(name),
+
             // It's not exactly an anon const, but wrt DefPathData, there
             // is no difference.
             DefKind::Static { nested: true, .. } => DefPathData::AnonConst,
@@ -276,9 +282,9 @@ impl DefKind {
             | DefKind::Static { .. }
             | DefKind::AssocFn
             | DefKind::AssocConst
-            | DefKind::Field => DefPathData::ValueNs(name),
-            DefKind::Macro(..) => DefPathData::MacroNs(name),
-            DefKind::LifetimeParam => DefPathData::LifetimeNs(name),
+            | DefKind::Field => DefPathData::ValueNs(name.unwrap()),
+            DefKind::Macro(..) => DefPathData::MacroNs(name.unwrap()),
+            DefKind::LifetimeParam => DefPathData::LifetimeNs(name.unwrap()),
             DefKind::Ctor(..) => DefPathData::Ctor,
             DefKind::Use => DefPathData::Use,
             DefKind::ForeignMod => DefPathData::ForeignMod,

compiler/rustc_hir/src/definitions.rs

@@ -271,8 +271,9 @@ pub enum DefPathData {
     Use,
     /// A global asm item.
     GlobalAsm,
-    /// Something in the type namespace.
-    TypeNs(Symbol),
+    /// Something in the type namespace. Will be empty for RPITIT associated
+    /// types, which are given a synthetic name later, if necessary.
+    TypeNs(Option<Symbol>),
     /// Something in the value namespace.
     ValueNs(Symbol),
     /// Something in the macro namespace.
@@ -410,8 +411,9 @@ impl DefPathData {
     pub fn get_opt_name(&self) -> Option<Symbol> {
         use self::DefPathData::*;
         match *self {
-            TypeNs(name) if name == kw::Empty => None,
-            TypeNs(name) | ValueNs(name) | MacroNs(name) | LifetimeNs(name) => Some(name),
+            TypeNs(name) => name,
+
+            ValueNs(name) | MacroNs(name) | LifetimeNs(name) => Some(name),
 
             Impl | ForeignMod | CrateRoot | Use | GlobalAsm | Closure | Ctor | AnonConst
             | OpaqueTy => None,
@@ -421,12 +423,14 @@ impl DefPathData {
     pub fn name(&self) -> DefPathDataName {
         use self::DefPathData::*;
         match *self {
-            TypeNs(name) if name == kw::Empty => {
-                DefPathDataName::Anon { namespace: sym::synthetic }
-            }
-            TypeNs(name) | ValueNs(name) | MacroNs(name) | LifetimeNs(name) => {
-                DefPathDataName::Named(name)
+            TypeNs(name) => {
+                if let Some(name) = name {
+                    DefPathDataName::Named(name)
+                } else {
+                    DefPathDataName::Anon { namespace: sym::synthetic }
+                }
             }
+            ValueNs(name) | MacroNs(name) | LifetimeNs(name) => DefPathDataName::Named(name),
             // Note that this does not show up in user print-outs.
             CrateRoot => DefPathDataName::Anon { namespace: kw::Crate },
             Impl => DefPathDataName::Anon { namespace: kw::Impl },

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -1462,7 +1462,8 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
         for &(opaque_def_id, captures) in opaque_capture_scopes.iter().rev() {
             let mut captures = captures.borrow_mut();
             let remapped = *captures.entry(lifetime).or_insert_with(|| {
-                let feed = self.tcx.create_def(opaque_def_id, ident.name, DefKind::LifetimeParam);
+                let feed =
+                    self.tcx.create_def(opaque_def_id, Some(ident.name), DefKind::LifetimeParam);
                 feed.def_span(ident.span);
                 feed.def_ident_span(Some(ident.span));
                 feed.def_id()

compiler/rustc_hir_pretty/src/lib.rs

@@ -117,80 +117,6 @@ impl<'a> State<'a> {
                 ));
                 self.hardbreak()
             }
-            hir::Attribute::Parsed(AttributeKind::Deprecation { deprecation, .. }) => {
-                self.word("#[deprecated");
-
-                // There are three possible forms here:
-                // 1. a form with explicit components like
-                //    `#[deprecated(since = "1.2.3", note = "some note", suggestion = "something")]`
-                //    where each component may be present or absent.
-                // 2. `#[deprecated = "message"]`
-                // 3. `#[deprecated]`
-                //
-                // Let's figure out which we need.
-                // If there's a `since` or `suggestion` value, we're definitely in form 1.
-                if matches!(
-                    deprecation.since,
-                    rustc_attr_parsing::DeprecatedSince::RustcVersion(..)
-                        | rustc_attr_parsing::DeprecatedSince::Future
-                        | rustc_attr_parsing::DeprecatedSince::NonStandard(..)
-                ) || deprecation.suggestion.is_some()
-                {
-                    self.word("(");
-                    let mut use_comma = false;
-
-                    match &deprecation.since {
-                        rustc_attr_parsing::DeprecatedSince::RustcVersion(rustc_version) => {
-                            self.word("since = \"");
-                            self.word(format!(
-                                "{}.{}.{}",
-                                rustc_version.major, rustc_version.minor, rustc_version.patch
-                            ));
-                            self.word("\"");
-                            use_comma = true;
-                        }
-                        rustc_attr_parsing::DeprecatedSince::Future => {
-                            self.word("since = \"future\"");
-                            use_comma = true;
-                        }
-                        rustc_attr_parsing::DeprecatedSince::NonStandard(symbol) => {
-                            self.word("since = \"");
-                            self.word(symbol.to_ident_string());
-                            self.word("\"");
-                            use_comma = true;
-                        }
-                        _ => {}
-                    }
-
-                    if let Some(note) = &deprecation.note {
-                        if use_comma {
-                            self.word(", ");
-                        }
-                        self.word("note = \"");
-                        self.word(note.to_ident_string());
-                        self.word("\"");
-                        use_comma = true;
-                    }
-
-                    if let Some(suggestion) = &deprecation.suggestion {
-                        if use_comma {
-                            self.word(", ");
-                        }
-                        self.word("suggestion = \"");
-                        self.word(suggestion.to_ident_string());
-                        self.word("\"");
-                    }
-                } else if let Some(note) = &deprecation.note {
-                    // We're in form 2: `#[deprecated = "message"]`.
-                    self.word(" = \"");
-                    self.word(note.to_ident_string());
-                    self.word("\"");
-                } else {
-                    // We're in form 3: `#[deprecated]`. Nothing to do here.
-                }
-
-                self.word("]");
-            }
             hir::Attribute::Parsed(pa) => {
                 self.word("#[attr=\"");
                 pa.print_attribute(self);

compiler/rustc_middle/src/ty/context.rs

@@ -1890,7 +1890,7 @@ impl<'tcx> TyCtxtAt<'tcx> {
     pub fn create_def(
         self,
         parent: LocalDefId,
-        name: Symbol,
+        name: Option<Symbol>,
         def_kind: DefKind,
     ) -> TyCtxtFeed<'tcx, LocalDefId> {
         let feed = self.tcx.create_def(parent, name, def_kind);
@@ -1905,7 +1905,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn create_def(
         self,
         parent: LocalDefId,
-        name: Symbol,
+        name: Option<Symbol>,
         def_kind: DefKind,
     ) -> TyCtxtFeed<'tcx, LocalDefId> {
         let data = def_kind.def_path_data(name);

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

@@ -569,7 +569,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
             // the children of the visible parent (as was done when computing
             // `visible_parent_map`), looking for the specific child we currently have and then
             // have access to the re-exported name.
-            DefPathData::TypeNs(ref mut name) if Some(visible_parent) != actual_parent => {
+            DefPathData::TypeNs(Some(ref mut name)) if Some(visible_parent) != actual_parent => {
                 // Item might be re-exported several times, but filter for the one
                 // that's public and whose identifier isn't `_`.
                 let reexport = self
@@ -590,7 +590,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
             }
             // Re-exported `extern crate` (#43189).
             DefPathData::CrateRoot => {
-                data = DefPathData::TypeNs(self.tcx().crate_name(def_id.krate));
+                data = DefPathData::TypeNs(Some(self.tcx().crate_name(def_id.krate)));
             }
             _ => {}
         }

compiler/rustc_middle/src/ty/significant_drop_order.rs

@@ -23,9 +23,11 @@ fn true_significant_drop_ty<'tcx>(
 
             match key.disambiguated_data.data {
                 rustc_hir::definitions::DefPathData::CrateRoot => {
-                    name_rev.push(tcx.crate_name(did.krate))
+                    name_rev.push(tcx.crate_name(did.krate));
+                }
+                rustc_hir::definitions::DefPathData::TypeNs(symbol) => {
+                    name_rev.push(symbol.unwrap());
                 }
-                rustc_hir::definitions::DefPathData::TypeNs(symbol) => name_rev.push(symbol),
                 _ => return None,
             }
             if let Some(parent) = key.parent {