Auto merge of rust-lang#117264 - TaKO8Ki:rollup-6jl1ynm, r=TaKO8Ki

Rollup of 5 pull requests

Successful merges:

 - rust-lang#114998 (feat(docs): add cargo-pgo to PGO documentation 📝)
 - rust-lang#116858 (Suggest assoc fn `new` when trying to build tuple struct with private fields)
 - rust-lang#116868 (Tweak suggestion span for outer attr and point at item following invalid inner attr)
 - rust-lang#117025 (Cleanup and improve `--check-cfg` implementation)
 - rust-lang#117240 (Fix documentation typo in std::iter::Iterator::collect_into)

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

Author: bors

compiler/rustc_interface/src/interface.rs

@@ -393,6 +393,9 @@ passes_invalid_attr_at_crate_level =
     `{$name}` attribute cannot be used at crate level
     .suggestion = perhaps you meant to use an outer attribute
 
+passes_invalid_attr_at_crate_level_item =
+    the inner attribute doesn't annotate this {$kind}
+
 passes_invalid_deprecation_version =
     invalid deprecation version found
     .label = invalid deprecation version

compiler/rustc_passes/messages.ftl

@@ -2534,10 +2534,30 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
         if attr.style == AttrStyle::Inner {
             for attr_to_check in ATTRS_TO_CHECK {
                 if attr.has_name(*attr_to_check) {
+                    let item = tcx
+                        .hir()
+                        .items()
+                        .map(|id| tcx.hir().item(id))
+                        .find(|item| !item.span.is_dummy()) // Skip prelude `use`s
+                        .map(|item| errors::ItemFollowingInnerAttr {
+                            span: item.ident.span,
+                            kind: item.kind.descr(),
+                        });
                     tcx.sess.emit_err(errors::InvalidAttrAtCrateLevel {
                         span: attr.span,
-                        snippet: tcx.sess.source_map().span_to_snippet(attr.span).ok(),
+                        sugg_span: tcx
+                            .sess
+                            .source_map()
+                            .span_to_snippet(attr.span)
+                            .ok()
+                            .filter(|src| src.starts_with("#!["))
+                            .map(|_| {
+                                attr.span
+                                    .with_lo(attr.span.lo() + BytePos(1))
+                                    .with_hi(attr.span.lo() + BytePos(2))
+                            }),
                         name: *attr_to_check,
+                        item,
                     });
                 }
             }

compiler/rustc_passes/src/check_attr.rs

@@ -856,8 +856,15 @@ pub struct UnknownLangItem {
 
 pub struct InvalidAttrAtCrateLevel {
     pub span: Span,
-    pub snippet: Option<String>,
+    pub sugg_span: Option<Span>,
     pub name: Symbol,
+    pub item: Option<ItemFollowingInnerAttr>,
+}
+
+#[derive(Clone, Copy)]
+pub struct ItemFollowingInnerAttr {
+    pub span: Span,
+    pub kind: &'static str,
 }
 
 impl IntoDiagnostic<'_> for InvalidAttrAtCrateLevel {
@@ -871,15 +878,18 @@ impl IntoDiagnostic<'_> for InvalidAttrAtCrateLevel {
         diag.set_arg("name", self.name);
         // Only emit an error with a suggestion if we can create a string out
         // of the attribute span
-        if let Some(src) = self.snippet {
-            let replacement = src.replace("#!", "#");
+        if let Some(span) = self.sugg_span {
             diag.span_suggestion_verbose(
-                self.span,
+                span,
                 fluent::passes_suggestion,
-                replacement,
+                String::new(),
                 rustc_errors::Applicability::MachineApplicable,
             );
         }
+        if let Some(item) = self.item {
+            diag.set_arg("kind", item.kind);
+            diag.span_label(item.span, fluent::passes_invalid_attr_at_crate_level_item);
+        }
         diag
     }
 }

compiler/rustc_passes/src/errors.rs

@@ -1570,7 +1570,26 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                         err.set_primary_message(
                             "cannot initialize a tuple struct which contains private fields",
                         );
-
+                        if !def_id.is_local()
+                            && self
+                                .r
+                                .tcx
+                                .inherent_impls(def_id)
+                                .iter()
+                                .flat_map(|impl_def_id| {
+                                    self.r.tcx.provided_trait_methods(*impl_def_id)
+                                })
+                                .any(|assoc| !assoc.fn_has_self_parameter && assoc.name == sym::new)
+                        {
+                            // FIXME: look for associated functions with Self return type,
+                            // instead of relying only on the name and lack of self receiver.
+                            err.span_suggestion_verbose(
+                                span.shrink_to_hi(),
+                                "you might have meant to use the `new` associated function",
+                                "::new".to_string(),
+                                Applicability::MaybeIncorrect,
+                            );
+                        }
                         // Use spans of the tuple struct definition.
                         self.r.field_def_ids(def_id).map(|field_ids| {
                             field_ids

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -2142,7 +2142,7 @@ pub trait Iterator {
     /// passed collection. The collection is then returned, so the call chain
     /// can be continued.
     ///
-    /// This is useful when you already have a collection and wants to add
+    /// This is useful when you already have a collection and want to add
     /// the iterator items to it.
     ///
     /// This method is a convenience method to call [Extend::extend](trait.Extend.html),

library/core/src/iter/traits/iterator.rs

@@ -145,3 +145,26 @@ in Clang's documentation is therefore an interesting read for anyone who wants
 to use PGO with Rust.
 
 [clang-pgo]: https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization
+
+## Community Maintained Tools
+
+As an alternative to directly using the compiler for Profile-Guided Optimization,
+you may choose to go with `cargo-pgo`, which has an intuitive command-line API
+and saves you the trouble of doing all the manual work. You can read more about
+it in their repository accessible from this link: https://github.com/Kobzol/cargo-pgo
+
+For the sake of completeness, here are the corresponding steps using `cargo-pgo`:
+
+```bash
+# Install if you haven't already
+cargo install cargo-pgo
+
+cargo pgo build
+cargo pgo optimize
+```
+
+These steps will do the following just as before:
+
+1. Build an instrumented binary from the source code.
+2. Run the instrumented binary to gather PGO profiles.
+3. Use the gathered PGO profiles from the last step to build an optimized binary.

src/doc/rustc/src/profile-guided-optimization.md

@@ -139,7 +139,7 @@ fn do_mumble_frotz() {}
 
 ```bash
 # This turns on checking for feature values, but not for condition names.
-rustc --check-cfg 'configure(feature, values("zapping", "lasers"))' \
+rustc --check-cfg 'cfg(feature, values("zapping", "lasers"))' \
       --check-cfg 'cfg(any())' \
       --cfg 'feature="zapping"' -Z unstable-options
 ```

src/doc/unstable-book/src/compiler-flags/check-cfg.md

@@ -3,11 +3,15 @@ error: `unix_sigpipe` attribute cannot be used at crate level
    |
 LL | #![unix_sigpipe = "inherit"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | fn main() {}
+   |    ---- the inner attribute doesn't annotate this function
    |
 help: perhaps you meant to use an outer attribute
    |
-LL | #[unix_sigpipe = "inherit"]
-   | ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+LL - #![unix_sigpipe = "inherit"]
+LL + #[unix_sigpipe = "inherit"]
+   |
 
 error: aborting due to previous error
 

tests/ui/attributes/unix_sigpipe/unix_sigpipe-crate.stderr

@@ -0,0 +1,2 @@
+error: invalid `--check-cfg` argument: `cfg(any(),values())` (`values()` cannot be specified before the names)
+