Rollup of 6 pull requests

compiler/rustc_ast/src/attr/mod.rs

@@ -62,7 +62,7 @@ impl NestedMetaItem {
         self.meta_item().and_then(|meta_item| meta_item.ident())
     }
     pub fn name_or_empty(&self) -> Symbol {
-        self.ident().unwrap_or_else(Ident::invalid).name
+        self.ident().unwrap_or_else(Ident::empty).name
     }
 
     /// Gets the string value if `self` is a `MetaItem` and the `MetaItem` is a
@@ -131,7 +131,7 @@ impl Attribute {
         }
     }
     pub fn name_or_empty(&self) -> Symbol {
-        self.ident().unwrap_or_else(Ident::invalid).name
+        self.ident().unwrap_or_else(Ident::empty).name
     }
 
     pub fn value_str(&self) -> Option<Symbol> {
@@ -166,7 +166,7 @@ impl MetaItem {
         if self.path.segments.len() == 1 { Some(self.path.segments[0].ident) } else { None }
     }
     pub fn name_or_empty(&self) -> Symbol {
-        self.ident().unwrap_or_else(Ident::invalid).name
+        self.ident().unwrap_or_else(Ident::empty).name
     }
 
     // Example:

compiler/rustc_ast/src/mut_visit.rs

@@ -1060,7 +1060,7 @@ pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
         let item_vis =
             Visibility { kind: VisibilityKind::Public, span: span.shrink_to_lo(), tokens: None };
         let item = P(Item {
-            ident: Ident::invalid(),
+            ident: Ident::empty(),
             attrs,
             id: DUMMY_NODE_ID,
             vis: item_vis,

compiler/rustc_ast_lowering/src/lib.rs

@@ -1435,7 +1435,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         trace!("registering opaque type with id {:#?}", opaque_ty_id);
         let opaque_ty_item = hir::Item {
             def_id: opaque_ty_id,
-            ident: Ident::invalid(),
+            ident: Ident::empty(),
             kind: opaque_ty_item_kind,
             vis: respan(self.lower_span(span.shrink_to_lo()), hir::VisibilityKind::Inherited),
             span: self.lower_span(opaque_ty_span),

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -45,12 +45,12 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let item_msg;
         let reason;
         let mut opt_source = None;
-        let access_place_desc = self.describe_place(access_place.as_ref());
+        let access_place_desc = self.describe_any_place(access_place.as_ref());
         debug!("report_mutability_error: access_place_desc={:?}", access_place_desc);
 
         match the_place_err {
             PlaceRef { local, projection: [] } => {
-                item_msg = format!("`{}`", access_place_desc.unwrap());
+                item_msg = access_place_desc;
                 if access_place.as_local().is_some() {
                     reason = ", as it is not declared as mutable".to_string();
                 } else {
@@ -83,7 +83,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     // If we deref an immutable ref then the suggestion here doesn't help.
                     return;
                 } else {
-                    item_msg = format!("`{}`", access_place_desc.unwrap());
+                    item_msg = access_place_desc;
                     if self.is_upvar_field_projection(access_place.as_ref()).is_some() {
                         reason = ", as it is not declared as mutable".to_string();
                     } else {
@@ -96,17 +96,17 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             PlaceRef { local, projection: [ProjectionElem::Deref] }
                 if self.body.local_decls[local].is_ref_for_guard() =>
             {
-                item_msg = format!("`{}`", access_place_desc.unwrap());
+                item_msg = access_place_desc;
                 reason = ", as it is immutable for the pattern guard".to_string();
             }
             PlaceRef { local, projection: [ProjectionElem::Deref] }
                 if self.body.local_decls[local].is_ref_to_static() =>
             {
                 if access_place.projection.len() == 1 {
-                    item_msg = format!("immutable static item `{}`", access_place_desc.unwrap());
+                    item_msg = format!("immutable static item {}", access_place_desc);
                     reason = String::new();
                 } else {
-                    item_msg = format!("`{}`", access_place_desc.unwrap());
+                    item_msg = access_place_desc;
                     let local_info = &self.body.local_decls[local].local_info;
                     if let Some(box LocalInfo::StaticRef { def_id, .. }) = *local_info {
                         let static_name = &self.infcx.tcx.item_name(def_id);
@@ -121,7 +121,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     && proj_base.is_empty()
                     && !self.upvars.is_empty()
                 {
-                    item_msg = format!("`{}`", access_place_desc.unwrap());
+                    item_msg = access_place_desc;
                     debug_assert!(
                         self.body.local_decls[ty::CAPTURE_STRUCT_LOCAL].ty.is_region_ptr()
                     );
@@ -147,7 +147,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     });
                     let pointer_type = source.describe_for_immutable_place(self.infcx.tcx);
                     opt_source = Some(source);
-                    if let Some(desc) = access_place_desc {
+                    if let Some(desc) = self.describe_place(access_place.as_ref()) {
                         item_msg = format!("`{}`", desc);
                         reason = match error_access {
                             AccessKind::Mutate => format!(", which is behind {}", pointer_type),

compiler/rustc_builtin_macros/src/asm.rs

@@ -812,7 +812,7 @@ pub fn expand_global_asm<'cx>(
         Ok(args) => {
             if let Some(inline_asm) = expand_preparsed_asm(ecx, args) {
                 MacEager::items(smallvec![P(ast::Item {
-                    ident: Ident::invalid(),
+                    ident: Ident::empty(),
                     attrs: Vec::new(),
                     id: ast::DUMMY_NODE_ID,
                     kind: ast::ItemKind::GlobalAsm(inline_asm),

compiler/rustc_builtin_macros/src/derive.rs

@@ -85,7 +85,7 @@ impl MultiItemModifier for Expander {
 fn dummy_annotatable() -> Annotatable {
     Annotatable::GenericParam(ast::GenericParam {
         id: ast::DUMMY_NODE_ID,
-        ident: Ident::invalid(),
+        ident: Ident::empty(),
         attrs: Default::default(),
         bounds: Default::default(),
         is_placeholder: false,

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -724,7 +724,7 @@ impl<'a> TraitDef<'a> {
 
         cx.item(
             self.span,
-            Ident::invalid(),
+            Ident::empty(),
             a,
             ast::ItemKind::Impl(Box::new(ast::ImplKind {
                 unsafety,

compiler/rustc_builtin_macros/src/deriving/mod.rs

@@ -178,7 +178,7 @@ fn inject_impl_of_structural_trait(
 
     let newitem = cx.item(
         span,
-        Ident::invalid(),
+        Ident::empty(),
         attrs,
         ItemKind::Impl(Box::new(ImplKind {
             unsafety: ast::Unsafe::No,

compiler/rustc_builtin_macros/src/standard_library_imports.rs

@@ -77,7 +77,7 @@ pub fn inject(
 
     let use_item = cx.item(
         span,
-        Ident::invalid(),
+        Ident::empty(),
         vec![cx.attribute(cx.meta_word(span, sym::prelude_import))],
         ast::ItemKind::Use(ast::UseTree {
             prefix: cx.path(span, import_path),

compiler/rustc_expand/src/expand.rs

@@ -383,7 +383,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 Unsafe::No,
                 ModKind::Loaded(krate.items, Inline::Yes, krate.span)
             ),
-            ident: Ident::invalid(),
+            ident: Ident::empty(),
             id: ast::DUMMY_NODE_ID,
             vis: ast::Visibility {
                 span: krate.span.shrink_to_lo(),
@@ -1426,7 +1426,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
                     _ => unreachable!(),
                 })
             }
-            ast::ItemKind::Mod(_, ref mut mod_kind) if ident != Ident::invalid() => {
+            ast::ItemKind::Mod(_, ref mut mod_kind) if ident != Ident::empty() => {
                 let (file_path, dir_path, dir_ownership) = match mod_kind {
                     ModKind::Loaded(_, inline, _) => {
                         // Inline `mod foo { ... }`, but we still need to push directories.
@@ -1508,7 +1508,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
             _ => {
                 item.attrs = attrs;
                 // The crate root is special - don't assign an ID to it.
-                if !(matches!(item.kind, ast::ItemKind::Mod(..)) && ident == Ident::invalid()) {
+                if !(matches!(item.kind, ast::ItemKind::Mod(..)) && ident == Ident::empty()) {
                     assign_id!(self, &mut item.id, || noop_flat_map_item(item, self))
                 } else {
                     noop_flat_map_item(item, self)

compiler/rustc_expand/src/mbe/quoted.rs

@@ -204,7 +204,7 @@ fn parse_tree(
                         pprust::token_to_string(&token),
                     );
                     sess.span_diagnostic.span_err(token.span, &msg);
-                    TokenTree::MetaVar(token.span, Ident::invalid())
+                    TokenTree::MetaVar(token.span, Ident::empty())
                 }
 
                 // There are no more tokens. Just return the `$` we already have.

compiler/rustc_expand/src/placeholders.rs

@@ -23,7 +23,7 @@ pub fn placeholder(
         }
     }
 
-    let ident = Ident::invalid();
+    let ident = Ident::empty();
     let attrs = Vec::new();
     let vis = vis.unwrap_or(ast::Visibility {
         span: DUMMY_SP,

compiler/rustc_hir/src/hir.rs

@@ -121,7 +121,7 @@ impl LifetimeName {
         match *self {
             LifetimeName::ImplicitObjectLifetimeDefault
             | LifetimeName::Implicit
-            | LifetimeName::Error => Ident::invalid(),
+            | LifetimeName::Error => Ident::empty(),
             LifetimeName::Underscore => Ident::with_dummy_span(kw::UnderscoreLifetime),
             LifetimeName::Static => Ident::with_dummy_span(kw::StaticLifetime),
             LifetimeName::Param(param_name) => param_name.ident(),
@@ -233,7 +233,7 @@ impl<'hir> PathSegment<'hir> {
     }
 
     pub fn invalid() -> Self {
-        Self::from_ident(Ident::invalid())
+        Self::from_ident(Ident::empty())
     }
 
     pub fn args(&self) -> &GenericArgs<'hir> {
@@ -310,7 +310,7 @@ impl GenericArg<'_> {
     }
 
     pub fn is_synthetic(&self) -> bool {
-        matches!(self, GenericArg::Lifetime(lifetime) if lifetime.name.ident() == Ident::invalid())
+        matches!(self, GenericArg::Lifetime(lifetime) if lifetime.name.ident() == Ident::empty())
     }
 
     pub fn descr(&self) -> &'static str {

compiler/rustc_lint/src/builtin.rs

@@ -657,6 +657,24 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
             return;
         }
 
+        // If the method is an impl for an item with docs_hidden, don't doc.
+        if method_context(cx, impl_item.hir_id()) == MethodLateContext::PlainImpl {
+            let parent = cx.tcx.hir().get_parent_did(impl_item.hir_id());
+            let impl_ty = cx.tcx.type_of(parent);
+            let outerdef = match impl_ty.kind() {
+                ty::Adt(def, _) => Some(def.did),
+                ty::Foreign(def_id) => Some(*def_id),
+                _ => None,
+            };
+            let is_hidden = match outerdef {
+                Some(id) => cx.tcx.is_doc_hidden(id),
+                None => false,
+            };
+            if is_hidden {
+                return;
+            }
+        }
+
         let (article, desc) = cx.tcx.article_and_description(impl_item.def_id.to_def_id());
         self.check_missing_docs_attrs(cx, impl_item.def_id, impl_item.span, article, desc);
     }

compiler/rustc_lint_defs/src/builtin.rs

@@ -1957,7 +1957,7 @@ declare_lint! {
     /// [issue #50504]: https://github.com/rust-lang/rust/issues/50504
     /// [future-incompatible]: ../index.md#future-incompatible-lints
     pub PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
-    Warn,
+    Deny,
     "detects proc macro derives using inaccessible names from parent modules",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #83583 <https://github.com/rust-lang/rust/issues/83583>",
@@ -3253,7 +3253,7 @@ declare_lint! {
     /// [issue #83125]: https://github.com/rust-lang/rust/issues/83125
     /// [future-incompatible]: ../index.md#future-incompatible-lints
     pub PROC_MACRO_BACK_COMPAT,
-    Warn,
+    Deny,
     "detects usage of old versions of certain proc-macro crates",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #83125 <https://github.com/rust-lang/rust/issues/83125>",

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

@@ -443,7 +443,7 @@ impl<'hir> Map<'hir> {
     pub fn body_param_names(&self, id: BodyId) -> impl Iterator<Item = Ident> + 'hir {
         self.body(id).params.iter().map(|arg| match arg.pat.kind {
             PatKind::Binding(_, _, ident, _) => ident,
-            _ => Ident::new(kw::Empty, rustc_span::DUMMY_SP),
+            _ => Ident::empty(),
         })
     }
 

compiler/rustc_parse/src/parser/item.rs

@@ -216,7 +216,7 @@ impl<'a> Parser<'a> {
                 return Err(e);
             }
 
-            (Ident::invalid(), ItemKind::Use(tree))
+            (Ident::empty(), ItemKind::Use(tree))
         } else if self.check_fn_front_matter(def_final) {
             // FUNCTION ITEM
             let (ident, sig, generics, body) = self.parse_fn(attrs, req_name, lo)?;
@@ -287,7 +287,7 @@ impl<'a> Parser<'a> {
             return Ok(None);
         } else if macros_allowed && self.check_path() {
             // MACRO INVOCATION ITEM
-            (Ident::invalid(), ItemKind::MacCall(self.parse_item_macro(vis)?))
+            (Ident::empty(), ItemKind::MacCall(self.parse_item_macro(vis)?))
         } else {
             return Ok(None);
         };
@@ -586,7 +586,7 @@ impl<'a> Parser<'a> {
             }
         };
 
-        Ok((Ident::invalid(), item_kind))
+        Ok((Ident::empty(), item_kind))
     }
 
     fn parse_item_list<T>(
@@ -933,7 +933,7 @@ impl<'a> Parser<'a> {
         let abi = self.parse_abi(); // ABI?
         let items = self.parse_item_list(attrs, |p| p.parse_foreign_item(ForceCollect::No))?;
         let module = ast::ForeignMod { unsafety, abi, items };
-        Ok((Ident::invalid(), ItemKind::ForeignMod(module)))
+        Ok((Ident::empty(), ItemKind::ForeignMod(module)))
     }
 
     /// Parses a foreign item (one in an `extern { ... }` block).

compiler/rustc_parse/src/parser/stmt.rs

@@ -16,7 +16,7 @@ use rustc_ast::{
 };
 use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, Local, Stmt};
 use rustc_ast::{StmtKind, DUMMY_NODE_ID};
-use rustc_errors::{Applicability, PResult};
+use rustc_errors::{Applicability, DiagnosticBuilder, PResult};
 use rustc_span::source_map::{BytePos, Span};
 use rustc_span::symbol::{kw, sym};
 
@@ -300,6 +300,12 @@ impl<'a> Parser<'a> {
             None => LocalKind::Decl,
             Some(init) => {
                 if self.eat_keyword(kw::Else) {
+                    if self.token.is_keyword(kw::If) {
+                        // `let...else if`. Emit the same error that `parse_block()` would,
+                        // but explicitly point out that this pattern is not allowed.
+                        let msg = "conditional `else if` is not supported for `let...else`";
+                        return Err(self.error_block_no_opening_brace_msg(msg));
+                    }
                     let els = self.parse_block()?;
                     self.check_let_else_init_bool_expr(&init);
                     self.check_let_else_init_trailing_brace(&init);
@@ -392,10 +398,9 @@ impl<'a> Parser<'a> {
         Ok(block)
     }
 
-    fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> {
+    fn error_block_no_opening_brace_msg(&mut self, msg: &str) -> DiagnosticBuilder<'a> {
         let sp = self.token.span;
-        let tok = super::token_descr(&self.token);
-        let mut e = self.struct_span_err(sp, &format!("expected `{{`, found {}", tok));
+        let mut e = self.struct_span_err(sp, msg);
         let do_not_suggest_help = self.token.is_keyword(kw::In) || self.token == token::Colon;
 
         // Check to see if the user has written something like
@@ -435,7 +440,13 @@ impl<'a> Parser<'a> {
             _ => {}
         }
         e.span_label(sp, "expected `{`");
-        Err(e)
+        e
+    }
+
+    fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> {
+        let tok = super::token_descr(&self.token);
+        let msg = format!("expected `{{`, found {}", tok);
+        Err(self.error_block_no_opening_brace_msg(&msg))
     }
 
     /// Parses a block. Inner attributes are allowed.

compiler/rustc_resolve/src/diagnostics.rs

@@ -1327,7 +1327,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                 if fst.ident.span.rust_2018() && !fst.ident.is_path_segment_keyword() =>
             {
                 // Insert a placeholder that's later replaced by `self`/`super`/etc.
-                path.insert(0, Segment::from_ident(Ident::invalid()));
+                path.insert(0, Segment::from_ident(Ident::empty()));
             }
             _ => return None,
         }

compiler/rustc_resolve/src/imports.rs

@@ -978,7 +978,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                     // HACK(eddyb) `lint_if_path_starts_with_module` needs at least
                     // 2 segments, so the `resolve_path` above won't trigger it.
                     let mut full_path = import.module_path.clone();
-                    full_path.push(Segment::from_ident(Ident::invalid()));
+                    full_path.push(Segment::from_ident(Ident::empty()));
                     self.r.lint_if_path_starts_with_module(
                         import.crate_lint(),
                         &full_path,