Auto merge of #139169 - matthiaskrgr:rollup-nfy4aew, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #138176 (Prefer built-in sized impls (and only sized impls) for rigid types always)
 - #138749 (Fix closure recovery for missing block when return type is specified)
 - #138842 (Emit `unused_attributes` for `#[inline]` on exported functions)
 - #139153 (Encode synthetic by-move coroutine body with a different `DefPathData`)
 - #139157 (Remove mention of `exhaustive_patterns` from `never` docs)
 - #139167 (Remove Amanieu from the libs review rotation)

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

Author: bors

compiler/rustc_hir/src/def.rs

@@ -294,7 +294,7 @@ impl DefKind {
             DefKind::GlobalAsm => DefPathData::GlobalAsm,
             DefKind::Impl { .. } => DefPathData::Impl,
             DefKind::Closure => DefPathData::Closure,
-            DefKind::SyntheticCoroutineBody => DefPathData::Closure,
+            DefKind::SyntheticCoroutineBody => DefPathData::SyntheticCoroutineBody,
         }
     }
 

compiler/rustc_hir/src/definitions.rs

@@ -291,6 +291,8 @@ pub enum DefPathData {
     /// An existential `impl Trait` type node.
     /// Argument position `impl Trait` have a `TypeNs` with their pretty-printed name.
     OpaqueTy,
+    /// A synthetic body for a coroutine's by-move body.
+    SyntheticCoroutineBody,
 }
 
 impl Definitions {
@@ -415,8 +417,16 @@ impl DefPathData {
 
             ValueNs(name) | MacroNs(name) | LifetimeNs(name) => Some(name),
 
-            Impl | ForeignMod | CrateRoot | Use | GlobalAsm | Closure | Ctor | AnonConst
-            | OpaqueTy => None,
+            Impl
+            | ForeignMod
+            | CrateRoot
+            | Use
+            | GlobalAsm
+            | Closure
+            | Ctor
+            | AnonConst
+            | OpaqueTy
+            | SyntheticCoroutineBody => None,
         }
     }
 
@@ -441,6 +451,7 @@ impl DefPathData {
             Ctor => DefPathDataName::Anon { namespace: sym::constructor },
             AnonConst => DefPathDataName::Anon { namespace: sym::constant },
             OpaqueTy => DefPathDataName::Anon { namespace: sym::opaque },
+            SyntheticCoroutineBody => DefPathDataName::Anon { namespace: sym::synthetic },
         }
     }
 }

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

@@ -172,6 +172,8 @@ impl CodegenFnAttrs {
     /// * `#[no_mangle]` is present
     /// * `#[export_name(...)]` is present
     /// * `#[linkage]` is present
+    ///
+    /// Keep this in sync with the logic for the unused_attributes for `#[inline]` lint.
     pub fn contains_extern_indicator(&self) -> bool {
         self.flags.contains(CodegenFnAttrFlags::NO_MANGLE)
             || self.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)

compiler/rustc_middle/src/mir/mono.rs

@@ -150,6 +150,7 @@ impl<'tcx> MonoItem<'tcx> {
 
         // If the function is #[naked] or contains any other attribute that requires exactly-once
         // instantiation:
+        // We emit an unused_attributes lint for this case, which should be kept in sync if possible.
         let codegen_fn_attrs = tcx.codegen_fn_attrs(instance.def_id());
         if codegen_fn_attrs.contains_extern_indicator()
             || codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED)

compiler/rustc_middle/src/traits/select.rs

@@ -95,10 +95,16 @@ pub type EvaluationCache<'tcx, ENV> = Cache<(ENV, ty::PolyTraitPredicate<'tcx>),
 /// parameter environment.
 #[derive(PartialEq, Eq, Debug, Clone, TypeVisitable)]
 pub enum SelectionCandidate<'tcx> {
+    /// A built-in implementation for the `Sized` trait. This is preferred
+    /// over all other candidates.
+    SizedCandidate {
+        has_nested: bool,
+    },
+
     /// A builtin implementation for some specific traits, used in cases
     /// where we cannot rely an ordinary library implementations.
     ///
-    /// The most notable examples are `sized`, `Copy` and `Clone`. This is also
+    /// The most notable examples are `Copy` and `Clone`. This is also
     /// used for the `DiscriminantKind` and `Pointee` trait, both of which have
     /// an associated type.
     BuiltinCandidate {

compiler/rustc_middle/src/ty/context.rs

@@ -1930,10 +1930,10 @@ impl<'tcx> TyCtxt<'tcx> {
         // As a consequence, this LocalDefId is always re-created before it is needed by the incr.
         // comp. engine itself.
         //
-        // This call also writes to the value of `source_span` and `expn_that_defined` queries.
+        // This call also writes to the value of the `source_span` query.
         // This is fine because:
-        // - those queries are `eval_always` so we won't miss their result changing;
-        // - this write will have happened before these queries are called.
+        // - that query is `eval_always` so we won't miss its result changing;
+        // - this write will have happened before that query is called.
         let def_id = self.untracked.definitions.write().create_def(parent, data);
 
         // This function modifies `self.definitions` using a side-effect.

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

@@ -139,8 +139,7 @@ pub trait Printer<'tcx>: Sized {
 
                     match key.disambiguated_data.data {
                         DefPathData::Closure => {
-                            // FIXME(async_closures): This is somewhat ugly.
-                            // We need to additionally print the `kind` field of a closure if
+                            // We need to additionally print the `kind` field of a coroutine if
                             // it is desugared from a coroutine-closure.
                             if let Some(hir::CoroutineKind::Desugared(
                                 _,
@@ -156,6 +155,10 @@ pub trait Printer<'tcx>: Sized {
                                 // Closures' own generics are only captures, don't print them.
                             }
                         }
+                        DefPathData::SyntheticCoroutineBody => {
+                            // Synthetic coroutine bodies have no distinct generics, since like
+                            // closures they're all just internal state of the coroutine.
+                        }
                         // This covers both `DefKind::AnonConst` and `DefKind::InlineConst`.
                         // Anon consts doesn't have their own generics, and inline consts' own
                         // generics are their inferred types, so don't print them.

compiler/rustc_parse/src/errors.rs

@@ -810,16 +810,16 @@ pub(crate) enum WrapInParentheses {
 
 #[derive(Diagnostic)]
 #[diag(parse_array_brackets_instead_of_braces)]
-pub(crate) struct ArrayBracketsInsteadOfSpaces {
+pub(crate) struct ArrayBracketsInsteadOfBraces {
     #[primary_span]
     pub span: Span,
     #[subdiagnostic]
-    pub sub: ArrayBracketsInsteadOfSpacesSugg,
+    pub sub: ArrayBracketsInsteadOfBracesSugg,
 }
 
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(parse_suggestion, applicability = "maybe-incorrect")]
-pub(crate) struct ArrayBracketsInsteadOfSpacesSugg {
+pub(crate) struct ArrayBracketsInsteadOfBracesSugg {
     #[suggestion_part(code = "[")]
     pub left: Span,
     #[suggestion_part(code = "]")]

compiler/rustc_parse/src/parser/expr.rs

@@ -2200,7 +2200,9 @@ impl<'a> Parser<'a> {
     }
 
     fn is_array_like_block(&mut self) -> bool {
-        self.look_ahead(1, |t| matches!(t.kind, TokenKind::Ident(..) | TokenKind::Literal(_)))
+        matches!(self.token.kind, TokenKind::OpenDelim(Delimiter::Brace))
+            && self
+                .look_ahead(1, |t| matches!(t.kind, TokenKind::Ident(..) | TokenKind::Literal(_)))
             && self.look_ahead(2, |t| t == &token::Comma)
             && self.look_ahead(3, |t| t.can_begin_expr())
     }
@@ -2212,9 +2214,9 @@ impl<'a> Parser<'a> {
         let mut snapshot = self.create_snapshot_for_diagnostic();
         match snapshot.parse_expr_array_or_repeat(exp!(CloseBrace)) {
             Ok(arr) => {
-                let guar = self.dcx().emit_err(errors::ArrayBracketsInsteadOfSpaces {
+                let guar = self.dcx().emit_err(errors::ArrayBracketsInsteadOfBraces {
                     span: arr.span,
-                    sub: errors::ArrayBracketsInsteadOfSpacesSugg {
+                    sub: errors::ArrayBracketsInsteadOfBracesSugg {
                         left: lo,
                         right: snapshot.prev_token.span,
                     },
@@ -2337,7 +2339,8 @@ impl<'a> Parser<'a> {
         let capture_clause = self.parse_capture_clause()?;
         let (fn_decl, fn_arg_span) = self.parse_fn_block_decl()?;
         let decl_hi = self.prev_token.span;
-        let mut body = match fn_decl.output {
+        let mut body = match &fn_decl.output {
+            // No return type.
             FnRetTy::Default(_) => {
                 let restrictions =
                     self.restrictions - Restrictions::STMT_EXPR - Restrictions::ALLOW_LET;
@@ -2349,11 +2352,8 @@ impl<'a> Parser<'a> {
                     Err(err) => self.recover_closure_body(err, before, prev, token, lo, decl_hi)?,
                 }
             }
-            _ => {
-                // If an explicit return type is given, require a block to appear (RFC 968).
-                let body_lo = self.token.span;
-                self.parse_expr_block(None, body_lo, BlockCheckMode::Default)?
-            }
+            // Explicit return type (`->`) needs block `-> T { }`.
+            FnRetTy::Ty(ty) => self.parse_closure_block_body(ty.span)?,
         };
 
         match coroutine_kind {
@@ -2405,6 +2405,49 @@ impl<'a> Parser<'a> {
         Ok(closure)
     }
 
+    /// If an explicit return type is given, require a block to appear (RFC 968).
+    fn parse_closure_block_body(&mut self, ret_span: Span) -> PResult<'a, P<Expr>> {
+        if self.may_recover()
+            && self.token.can_begin_expr()
+            && !matches!(self.token.kind, TokenKind::OpenDelim(Delimiter::Brace))
+            && !self.token.is_whole_block()
+        {
+            let snapshot = self.create_snapshot_for_diagnostic();
+            let restrictions =
+                self.restrictions - Restrictions::STMT_EXPR - Restrictions::ALLOW_LET;
+            let tok = self.token.clone();
+            match self.parse_expr_res(restrictions, AttrWrapper::empty()) {
+                Ok((expr, _)) => {
+                    let descr = super::token_descr(&tok);
+                    let mut diag = self
+                        .dcx()
+                        .struct_span_err(tok.span, format!("expected `{{`, found {descr}"));
+                    diag.span_label(
+                        ret_span,
+                        "explicit return type requires closure body to be enclosed in braces",
+                    );
+                    diag.multipart_suggestion_verbose(
+                        "wrap the expression in curly braces",
+                        vec![
+                            (expr.span.shrink_to_lo(), "{ ".to_string()),
+                            (expr.span.shrink_to_hi(), " }".to_string()),
+                        ],
+                        Applicability::MachineApplicable,
+                    );
+                    diag.emit();
+                    return Ok(expr);
+                }
+                Err(diag) => {
+                    diag.cancel();
+                    self.restore_snapshot(snapshot);
+                }
+            }
+        }
+
+        let body_lo = self.token.span;
+        self.parse_expr_block(None, body_lo, BlockCheckMode::Default)
+    }
+
     /// Parses an optional `move` or `use` prefix to a closure-like construct.
     fn parse_capture_clause(&mut self) -> PResult<'a, CaptureBy> {
         if self.eat_keyword(exp!(Move)) {

compiler/rustc_passes/messages.ftl

@@ -383,6 +383,10 @@ passes_inline_ignored_constants =
     .warn = {-passes_previously_accepted}
     .note = {-passes_see_issue(issue: "65833")}
 
+passes_inline_ignored_for_exported =
+    `#[inline]` is ignored on externally exported functions
+    .help = externally exported functions are functions with `#[no_mangle]`, `#[export_name]`, or `#[linkage]`
+
 passes_inline_ignored_function_prototype =
     `#[inline]` is ignored on function prototypes