Auto merge of #109284 - matthiaskrgr:rollup-aaublsx, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #109102 (Erase escaping late-bound regions when probing for ambiguous associated types)
 - #109200 (Fix index out of bounds in `suggest_trait_fn_ty_for_impl_fn_infer`)
 - #109211 (E0206 - update description )
 - #109222 (Do not ICE for unexpected lifetime with ConstGeneric rib)
 - #109235 (fallback to lstat when stat fails on Windows)
 - #109248 (Pass the right HIR back from `get_fn_decl`)
 - #109251 (Suggest surrounding the macro with `{}` to interpret as a statement)
 - #109256 (Check for llvm-tools before install)
 - #109257 (resolve: Improve debug impls for `NameBinding`)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_error_codes/src/error_codes/E0206.md

@@ -1,5 +1,5 @@
-The `Copy` trait was implemented on a type which is neither a struct nor an
-enum.
+The `Copy` trait was implemented on a type which is neither a struct, an
+enum, nor a union.
 
 Erroneous code example:
 
@@ -10,6 +10,6 @@ struct Bar;
 impl Copy for &'static mut Bar { } // error!
 ```
 
-You can only implement `Copy` for a struct or an enum.
+You can only implement `Copy` for a struct, an enum, or a union.
 The previous example will fail because `&'static mut Bar`
-is not a struct or enum.
+is not a struct, an enum, or a union.

compiler/rustc_expand/src/mbe/diagnostics.rs

@@ -245,12 +245,24 @@ pub(super) fn emit_frag_parse_err(
                 e.note(
                     "the macro call doesn't expand to an expression, but it can expand to a statement",
                 );
-                e.span_suggestion_verbose(
-                    site_span.shrink_to_hi(),
-                    "add `;` to interpret the expansion as a statement",
-                    ";",
-                    Applicability::MaybeIncorrect,
-                );
+
+                if parser.token == token::Semi {
+                    if let Ok(snippet) = parser.sess.source_map().span_to_snippet(site_span) {
+                        e.span_suggestion_verbose(
+                            site_span,
+                            "surround the macro invocation with `{}` to interpret the expansion as a statement",
+                            format!("{{ {}; }}", snippet),
+                            Applicability::MaybeIncorrect,
+                        );
+                    }
+                } else {
+                    e.span_suggestion_verbose(
+                        site_span.shrink_to_hi(),
+                        "add `;` to interpret the expansion as a statement",
+                        ";",
+                        Applicability::MaybeIncorrect,
+                    );
+                }
             }
         },
         _ => annotate_err_with_kind(&mut e, kind, site_span),

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2396,13 +2396,24 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                     tcx,
                                     infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id),
                                 );
+                                // I guess we don't need to make a universe unless we need it,
+                                // but also we're on the error path, so it doesn't matter here.
+                                let universe = infcx.create_next_universe();
                                 infcx
                                     .can_eq(
                                         ty::ParamEnv::empty(),
                                         impl_.self_ty(),
-                                        // Must fold past escaping bound vars too,
-                                        // since we have those at this point in astconv.
-                                        tcx.fold_regions(qself_ty, |_, _| tcx.lifetimes.re_erased),
+                                        tcx.replace_escaping_bound_vars_uncached(qself_ty, ty::fold::FnMutDelegate {
+                                            regions: &mut |_| tcx.lifetimes.re_erased,
+                                            types: &mut |bv| tcx.mk_placeholder(ty::PlaceholderType {
+                                                universe,
+                                                name: bv.kind,
+                                            }),
+                                            consts: &mut |bv, ty| tcx.mk_const(ty::PlaceholderConst {
+                                                universe,
+                                                name: bv
+                                            }, ty),
+                                        })
                                     )
                             })
                             && tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative
@@ -3317,10 +3328,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             tcx,
             trait_ref.substs.extend_to(tcx, assoc.def_id, |param, _| tcx.mk_param_from_def(param)),
         );
+        let fn_sig = tcx.liberate_late_bound_regions(fn_hir_id.expect_owner().to_def_id(), fn_sig);
 
-        let ty = if let Some(arg_idx) = arg_idx { fn_sig.input(arg_idx) } else { fn_sig.output() };
-
-        Some(tcx.liberate_late_bound_regions(fn_hir_id.expect_owner().to_def_id(), ty))
+        Some(if let Some(arg_idx) = arg_idx {
+            *fn_sig.inputs().get(arg_idx)?
+        } else {
+            fn_sig.output()
+        })
     }
 
     #[instrument(level = "trace", skip(self, generate_err))]

compiler/rustc_hir_typeck/src/_match.rs

@@ -299,7 +299,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             {
                 // check that the `if` expr without `else` is the fn body's expr
                 if expr.span == sp {
-                    return self.get_fn_decl(hir_id).and_then(|(fn_decl, _)| {
+                    return self.get_fn_decl(hir_id).and_then(|(_, fn_decl, _)| {
                         let span = fn_decl.output.span();
                         let snippet = self.tcx.sess.source_map().span_to_snippet(span).ok()?;
                         Some((span, format!("expected `{snippet}` because of this return type")))

compiler/rustc_hir_typeck/src/coercion.rs

@@ -1722,12 +1722,13 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
                     fcx.suggest_semicolon_at_end(cond_expr.span, &mut err);
                 }
             }
-            fcx.get_node_fn_decl(parent).map(|(fn_decl, _, is_main)| (fn_decl, is_main))
+            fcx.get_node_fn_decl(parent)
+                .map(|(fn_id, fn_decl, _, is_main)| (fn_id, fn_decl, is_main))
         } else {
             fcx.get_fn_decl(parent_id)
         };
 
-        if let Some((fn_decl, can_suggest)) = fn_decl {
+        if let Some((fn_id, fn_decl, can_suggest)) = fn_decl {
             if blk_id.is_none() {
                 pointing_at_return_type |= fcx.suggest_missing_return_type(
                     &mut err,
@@ -1735,7 +1736,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
                     expected,
                     found,
                     can_suggest,
-                    fcx.tcx.hir().get_parent_item(id).into(),
+                    fn_id,
                 );
             }
             if !pointing_at_return_type {
@@ -1746,17 +1747,11 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         let parent_id = fcx.tcx.hir().get_parent_item(id);
         let parent_item = fcx.tcx.hir().get_by_def_id(parent_id.def_id);
 
-        if let (Some(expr), Some(_), Some((fn_decl, _, _))) =
+        if let (Some(expr), Some(_), Some((fn_id, fn_decl, _, _))) =
             (expression, blk_id, fcx.get_node_fn_decl(parent_item))
         {
             fcx.suggest_missing_break_or_return_expr(
-                &mut err,
-                expr,
-                fn_decl,
-                expected,
-                found,
-                id,
-                parent_id.into(),
+                &mut err, expr, fn_decl, expected, found, id, fn_id,
             );
         }
 
@@ -1882,7 +1877,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
     }
 
     fn is_return_ty_unsized<'a>(&self, fcx: &FnCtxt<'a, 'tcx>, blk_id: hir::HirId) -> bool {
-        if let Some((fn_decl, _)) = fcx.get_fn_decl(blk_id)
+        if let Some((_, fn_decl, _)) = fcx.get_fn_decl(blk_id)
             && let hir::FnRetTy::Return(ty) = fn_decl.output
             && let ty = fcx.astconv().ast_ty_to_ty( ty)
             && let ty::Dynamic(..) = ty.kind()

compiler/rustc_hir_typeck/src/expr.rs

@@ -788,7 +788,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.ret_coercion_span.set(Some(expr.span));
             }
             let cause = self.cause(expr.span, ObligationCauseCode::ReturnNoExpression);
-            if let Some((fn_decl, _)) = self.get_fn_decl(expr.hir_id) {
+            if let Some((_, fn_decl, _)) = self.get_fn_decl(expr.hir_id) {
                 coercion.coerce_forced_unit(
                     self,
                     &cause,

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -898,51 +898,74 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         )
     }
 
-    /// Given a function `Node`, return its `FnDecl` if it exists, or `None` otherwise.
+    /// Given a function `Node`, return its  `HirId` and `FnDecl` if it exists. Given a closure
+    /// that is the child of a function, return that function's `HirId` and `FnDecl` instead.
+    /// This may seem confusing at first, but this is used in diagnostics for `async fn`,
+    /// for example, where most of the type checking actually happens within a nested closure,
+    /// but we often want access to the parent function's signature.
+    ///
+    /// Otherwise, return false.
     pub(in super::super) fn get_node_fn_decl(
         &self,
         node: Node<'tcx>,
-    ) -> Option<(&'tcx hir::FnDecl<'tcx>, Ident, bool)> {
+    ) -> Option<(hir::HirId, &'tcx hir::FnDecl<'tcx>, Ident, bool)> {
         match node {
-            Node::Item(&hir::Item { ident, kind: hir::ItemKind::Fn(ref sig, ..), .. }) => {
+            Node::Item(&hir::Item {
+                ident,
+                kind: hir::ItemKind::Fn(ref sig, ..),
+                owner_id,
+                ..
+            }) => {
                 // This is less than ideal, it will not suggest a return type span on any
                 // method called `main`, regardless of whether it is actually the entry point,
                 // but it will still present it as the reason for the expected type.
-                Some((&sig.decl, ident, ident.name != sym::main))
+                Some((
+                    hir::HirId::make_owner(owner_id.def_id),
+                    &sig.decl,
+                    ident,
+                    ident.name != sym::main,
+                ))
             }
             Node::TraitItem(&hir::TraitItem {
                 ident,
                 kind: hir::TraitItemKind::Fn(ref sig, ..),
+                owner_id,
                 ..
-            }) => Some((&sig.decl, ident, true)),
+            }) => Some((hir::HirId::make_owner(owner_id.def_id), &sig.decl, ident, true)),
             Node::ImplItem(&hir::ImplItem {
                 ident,
                 kind: hir::ImplItemKind::Fn(ref sig, ..),
+                owner_id,
                 ..
-            }) => Some((&sig.decl, ident, false)),
-            Node::Expr(&hir::Expr {
-                hir_id,
-                kind: hir::ExprKind::Closure(..),
-                ..
-            }) if let Some(Node::Item(&hir::Item {
+            }) => Some((hir::HirId::make_owner(owner_id.def_id), &sig.decl, ident, false)),
+            Node::Expr(&hir::Expr { hir_id, kind: hir::ExprKind::Closure(..), .. })
+                if let Some(Node::Item(&hir::Item {
+                    ident,
+                    kind: hir::ItemKind::Fn(ref sig, ..),
+                    owner_id,
+                    ..
+                })) = self.tcx.hir().find_parent(hir_id) => Some((
+                hir::HirId::make_owner(owner_id.def_id),
+                &sig.decl,
                 ident,
-                kind: hir::ItemKind::Fn(ref sig, ..),
-                ..
-            })) = self.tcx.hir().find_parent(hir_id) => {
-                Some((&sig.decl, ident, ident.name != sym::main))
-            },
+                ident.name != sym::main,
+            )),
             _ => None,
         }
     }
 
-    /// Given a `HirId`, return the `FnDecl` of the method it is enclosed by and whether a
+    /// Given a `HirId`, return the `HirId` of the enclosing function, its `FnDecl`, and whether a
     /// suggestion can be made, `None` otherwise.
-    pub fn get_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl<'tcx>, bool)> {
+    pub fn get_fn_decl(
+        &self,
+        blk_id: hir::HirId,
+    ) -> Option<(hir::HirId, &'tcx hir::FnDecl<'tcx>, bool)> {
         // Get enclosing Fn, if it is a function or a trait method, unless there's a `loop` or
         // `while` before reaching it, as block tail returns are not available in them.
         self.tcx.hir().get_return_block(blk_id).and_then(|blk_id| {
             let parent = self.tcx.hir().get(blk_id);
-            self.get_node_fn_decl(parent).map(|(fn_decl, _, is_main)| (fn_decl, is_main))
+            self.get_node_fn_decl(parent)
+                .map(|(fn_id, fn_decl, _, is_main)| (fn_id, fn_decl, is_main))
         })
     }
 

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -1669,7 +1669,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Given a function block's `HirId`, returns its `FnDecl` if it exists, or `None` otherwise.
     fn get_parent_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl<'tcx>, Ident)> {
         let parent = self.tcx.hir().get_by_def_id(self.tcx.hir().get_parent_item(blk_id).def_id);
-        self.get_node_fn_decl(parent).map(|(fn_decl, ident, _)| (fn_decl, ident))
+        self.get_node_fn_decl(parent).map(|(_, fn_decl, ident, _)| (fn_decl, ident))
     }
 
     /// If `expr` is a `match` expression that has only one non-`!` arm, use that arm's tail

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -64,8 +64,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let expr = expr.peel_drop_temps();
         self.suggest_missing_semicolon(err, expr, expected, false);
         let mut pointing_at_return_type = false;
-        if let Some((fn_decl, can_suggest)) = self.get_fn_decl(blk_id) {
-            let fn_id = self.tcx.hir().get_return_block(blk_id).unwrap();
+        if let Some((fn_id, fn_decl, can_suggest)) = self.get_fn_decl(blk_id) {
             pointing_at_return_type = self.suggest_missing_return_type(
                 err,
                 &fn_decl,

compiler/rustc_resolve/src/imports.rs

@@ -85,20 +85,28 @@ impl<'a> std::fmt::Debug for ImportKind<'a> {
             Single {
                 ref source,
                 ref target,
+                ref source_bindings,
+                ref target_bindings,
                 ref type_ns_only,
                 ref nested,
                 ref id,
-                // Ignore the following to avoid an infinite loop while printing.
-                source_bindings: _,
-                target_bindings: _,
             } => f
                 .debug_struct("Single")
                 .field("source", source)
                 .field("target", target)
+                // Ignore the nested bindings to avoid an infinite loop while printing.
+                .field(
+                    "source_bindings",
+                    &source_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))),
+                )
+                .field(
+                    "target_bindings",
+                    &target_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))),
+                )
                 .field("type_ns_only", type_ns_only)
                 .field("nested", nested)
                 .field("id", id)
-                .finish_non_exhaustive(),
+                .finish(),
             Glob { ref is_prelude, ref max_vis, ref id } => f
                 .debug_struct("Glob")
                 .field("is_prelude", is_prelude)

compiler/rustc_resolve/src/late.rs

@@ -1478,8 +1478,9 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                                     } else {
                                         LifetimeUseSet::Many
                                     }),
-                                    LifetimeRibKind::Generics { .. } => None,
-                                    LifetimeRibKind::ConstGeneric | LifetimeRibKind::AnonConst => {
+                                    LifetimeRibKind::Generics { .. }
+                                    | LifetimeRibKind::ConstGeneric => None,
+                                    LifetimeRibKind::AnonConst => {
                                         span_bug!(ident.span, "unexpected rib kind: {:?}", rib.kind)
                                     }
                                 })

library/std/src/sys/windows/fs.rs

@@ -1236,7 +1236,17 @@ pub fn link(_original: &Path, _link: &Path) -> io::Result<()> {
 }
 
 pub fn stat(path: &Path) -> io::Result<FileAttr> {
-    metadata(path, ReparsePoint::Follow)
+    match metadata(path, ReparsePoint::Follow) {
+        Err(err) if err.raw_os_error() == Some(c::ERROR_CANT_ACCESS_FILE as i32) => {
+            if let Ok(attrs) = lstat(path) {
+                if !attrs.file_type().is_symlink() {
+                    return Ok(attrs);
+                }
+            }
+            Err(err)
+        }
+        result => result,
+    }
 }
 
 pub fn lstat(path: &Path) -> io::Result<FileAttr> {

src/bootstrap/install.rs

@@ -210,10 +210,13 @@ install!((self, builder, _config),
         }
     };
     LlvmTools, alias = "llvm-tools", Self::should_build(_config), only_hosts: true, {
-        let tarball = builder
-            .ensure(dist::LlvmTools { target: self.target })
-            .expect("missing llvm-tools");
-        install_sh(builder, "llvm-tools", self.compiler.stage, Some(self.target), &tarball);
+        if let Some(tarball) = builder.ensure(dist::LlvmTools { target: self.target }) {
+            install_sh(builder, "llvm-tools", self.compiler.stage, Some(self.target), &tarball);
+        } else {
+            builder.info(
+                &format!("skipping llvm-tools stage{} ({}): external LLVM", self.compiler.stage, self.target),
+            );
+        }
     };
     Rustfmt, alias = "rustfmt", Self::should_build(_config), only_hosts: true, {
         if let Some(tarball) = builder.ensure(dist::Rustfmt {

tests/ui/lifetimes/unusual-rib-combinations.rs

@@ -25,4 +25,9 @@ fn d<const C: S>() {}
 //~^ ERROR missing lifetime specifier
 //~| ERROR `S<'_>` is forbidden as the type of a const generic parameter
 
+trait Foo<'a> {}
+struct Bar<const N: &'a (dyn for<'a> Foo<'a>)>;
+//~^ ERROR use of non-static lifetime `'a` in const generic
+//~| ERROR `&dyn for<'a> Foo<'a>` is forbidden as the type of a const generic parameter
+
 fn main() {}

tests/ui/lifetimes/unusual-rib-combinations.stderr

@@ -9,6 +9,14 @@ help: consider introducing a named lifetime parameter
 LL | fn d<'a, const C: S<'a>>() {}
    |      +++           ++++
 
+error[E0771]: use of non-static lifetime `'a` in const generic
+  --> $DIR/unusual-rib-combinations.rs:29:22
+   |
+LL | struct Bar<const N: &'a (dyn for<'a> Foo<'a>)>;
+   |                      ^^
+   |
+   = note: for more information, see issue #74052 <https://github.com/rust-lang/rust/issues/74052>
+
 error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/unusual-rib-combinations.rs:7:16
    |
@@ -55,7 +63,16 @@ LL | fn d<const C: S>() {}
    = note: the only supported types are integers, `bool` and `char`
    = help: more complex types are supported with `#![feature(adt_const_params)]`
 
-error: aborting due to 7 previous errors
+error: `&dyn for<'a> Foo<'a>` is forbidden as the type of a const generic parameter
+  --> $DIR/unusual-rib-combinations.rs:29:21
+   |
+LL | struct Bar<const N: &'a (dyn for<'a> Foo<'a>)>;
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+   = help: more complex types are supported with `#![feature(adt_const_params)]`
 
-Some errors have detailed explanations: E0106, E0214, E0308.
+error: aborting due to 9 previous errors
+
+Some errors have detailed explanations: E0106, E0214, E0308, E0771.
 For more information about an error, try `rustc --explain E0106`.

tests/ui/macros/issue-109237.rs

@@ -0,0 +1,7 @@
+macro_rules! statement {
+    () => {;}; //~ ERROR expected expression
+}
+
+fn main() {
+    let _ = statement!();
+}

tests/ui/macros/issue-109237.stderr

@@ -0,0 +1,18 @@
+error: expected expression, found `;`
+  --> $DIR/issue-109237.rs:2:12
+   |
+LL |     () => {;};
+   |            ^ expected expression
+...
+LL |     let _ = statement!();
+   |             ------------ in this macro invocation
+   |
+   = note: the macro call doesn't expand to an expression, but it can expand to a statement
+   = note: this error originates in the macro `statement` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: surround the macro invocation with `{}` to interpret the expansion as a statement
+   |
+LL |     let _ = { statement!(); };
+   |             ~~~~~~~~~~~~~~~~~
+
+error: aborting due to previous error
+

tests/ui/suggestions/bad-infer-in-trait-impl.rs

@@ -0,0 +1,10 @@
+trait Foo {
+    fn bar();
+}
+
+impl Foo for () {
+    fn bar(s: _) {}
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+}
+
+fn main() {}

tests/ui/suggestions/bad-infer-in-trait-impl.stderr

@@ -0,0 +1,14 @@
+error[E0121]: the placeholder `_` is not allowed within types on item signatures for functions
+  --> $DIR/bad-infer-in-trait-impl.rs:6:15
+   |
+LL |     fn bar(s: _) {}
+   |               ^ not allowed in type signatures
+   |
+help: use type parameters instead
+   |
+LL |     fn bar<T>(s: T) {}
+   |           +++    ~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0121`.

tests/ui/suggestions/suggest-ret-on-async-w-late.rs

@@ -0,0 +1,11 @@
+// edition: 2021
+
+// Make sure we don't ICE when suggesting a return type
+// for an async fn that has late-bound vars...
+
+async fn ice(_: &i32) {
+    true
+    //~^ ERROR mismatched types
+}
+
+fn main() {}

tests/ui/suggestions/suggest-ret-on-async-w-late.stderr

@@ -0,0 +1,11 @@
+error[E0308]: mismatched types
+  --> $DIR/suggest-ret-on-async-w-late.rs:7:5
+   |
+LL | async fn ice(_: &i32) {
+   |                       - help: try adding a return type: `-> bool`
+LL |     true
+   |     ^^^^ expected `()`, found `bool`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/traits/non_lifetime_binders/missing-assoc-item.rs

@@ -0,0 +1,11 @@
+#![feature(non_lifetime_binders)]
+//~^ WARN the feature `non_lifetime_binders` is incomplete
+
+fn f()
+where
+    for<B> B::Item: Send,
+    //~^ ERROR ambiguous associated type
+{
+}
+
+fn main() {}

tests/ui/traits/non_lifetime_binders/missing-assoc-item.stderr

@@ -0,0 +1,18 @@
+warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/missing-assoc-item.rs:1:12
+   |
+LL | #![feature(non_lifetime_binders)]
+   |            ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0223]: ambiguous associated type
+  --> $DIR/missing-assoc-item.rs:6:12
+   |
+LL |     for<B> B::Item: Send,
+   |            ^^^^^^^ help: use the fully-qualified path: `<B as IntoIterator>::Item`
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0223`.