Auto merge of #83692 - Dylan-DPC:rollup-2a2m3jy, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #80720 (Make documentation of which items the prelude exports more readable.)
 - #83654 (Do not emit a suggestion that causes the E0632 error)
 - #83671 (Add a regression test for issue-75801)
 - #83678 (Fix Self keyword doc URL conflict on case insensitive file systems (until definitely fixed on rustdoc))
 - #83680 (Update for loop desugaring docs)
 - #83683 (bootstrap: don't complain about linkcheck if it is excluded)

Failed merges:

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

compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -287,6 +287,7 @@ pub struct InferenceDiagnosticsData {
 pub struct InferenceDiagnosticsParentData {
     pub prefix: &'static str,
     pub name: String,
+    pub def_id: DefId,
 }
 
 pub enum UnderspecifiedArgKind {
@@ -328,6 +329,7 @@ impl InferenceDiagnosticsParentData {
         Some(InferenceDiagnosticsParentData {
             prefix: tcx.def_kind(parent_def_id).descr(parent_def_id),
             name: parent_name,
+            def_id: parent_def_id,
         })
     }
 }
@@ -754,12 +756,30 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             if let (UnderspecifiedArgKind::Const { .. }, Some(parent_data)) =
                 (&arg_data.kind, &arg_data.parent)
             {
-                err.span_suggestion_verbose(
-                    span,
-                    "consider specifying the const argument",
-                    format!("{}::<{}>", parent_data.name, arg_data.name),
-                    Applicability::MaybeIncorrect,
-                );
+                let has_impl_trait =
+                    self.tcx.generics_of(parent_data.def_id).params.iter().any(|param| {
+                        matches!(
+                            param.kind,
+                            ty::GenericParamDefKind::Type {
+                                synthetic: Some(
+                                    hir::SyntheticTyParamKind::ImplTrait
+                                        | hir::SyntheticTyParamKind::FromAttr,
+                                ),
+                                ..
+                            }
+                        )
+                    });
+
+                // (#83606): Do not emit a suggestion if the parent has an `impl Trait`
+                // as an argument otherwise it will cause the E0282 error.
+                if !has_impl_trait {
+                    err.span_suggestion_verbose(
+                        span,
+                        "consider specifying the const argument",
+                        format!("{}::<{}>", parent_data.name, arg_data.name),
+                        Applicability::MaybeIncorrect,
+                    );
+                }
             }
 
             err.span_label(

library/std/src/keyword_docs.rs

@@ -547,15 +547,18 @@ mod fn_keyword {}
 /// # fn code() { }
 /// # let iterator = 0..2;
 /// {
-///     let mut _iter = std::iter::IntoIterator::into_iter(iterator);
-///     loop {
-///         match _iter.next() {
-///             Some(loop_variable) => {
-///                 code()
-///             },
-///             None => break,
-///         }
-///     }
+///     let result = match IntoIterator::into_iter(iterator) {
+///         mut iter => loop {
+///             let next;
+///             match iter.next() {
+///                 Some(val) => next = val,
+///                 None => break,
+///             };
+///             let loop_variable = next;
+///             let () = { code(); };
+///         },
+///     };
+///     result
 /// }
 /// ```
 ///
@@ -1310,7 +1313,11 @@ mod return_keyword {}
 /// [Reference]: ../reference/items/associated-items.html#methods
 mod self_keyword {}
 
-#[doc(keyword = "Self")]
+// FIXME: Once rustdoc can handle URL conflicts on case insensitive file systems, we can remove the
+// three next lines and put back: `#[doc(keyword = "Self")]`.
+#[doc(alias = "Self")]
+#[allow(rustc::existing_doc_keyword)]
+#[doc(keyword = "SelfTy")]
 //
 /// The implementing type within a [`trait`] or [`impl`] block, or the current type within a type
 /// definition.

library/std/src/prelude/mod.rs

@@ -28,53 +28,53 @@
 //! The current version of the prelude (version 1) lives in
 //! [`std::prelude::v1`], and re-exports the following:
 //!
-//! * [`std::marker`]::{[`Copy`], [`Send`], [`Sized`], [`Sync`], [`Unpin`]}:
+//! * <code>[std::marker]::{[Copy], [Send], [Sized], [Sync], [Unpin]}</code>,
 //!   marker traits that indicate fundamental properties of types.
-//! * [`std::ops`]::{[`Drop`], [`Fn`], [`FnMut`], [`FnOnce`]}: various
+//! * <code>[std::ops]::{[Drop], [Fn], [FnMut], [FnOnce]}</code>, various
 //!   operations for both destructors and overloading `()`.
-//! * [`std::mem`]::[`drop`][`mem::drop`]: a convenience function for explicitly
+//! * <code>[std::mem]::[drop][mem::drop]</code>, a convenience function for explicitly
 //!   dropping a value.
-//! * [`std::boxed`]::[`Box`]: a way to allocate values on the heap.
-//! * [`std::borrow`]::[`ToOwned`]: the conversion trait that defines
+//! * <code>[std::boxed]::[Box]</code>, a way to allocate values on the heap.
+//! * <code>[std::borrow]::[ToOwned]</code>, the conversion trait that defines
 //!   [`to_owned`], the generic method for creating an owned type from a
 //!   borrowed type.
-//! * [`std::clone`]::[`Clone`]: the ubiquitous trait that defines
-//!   [`clone`][`Clone::clone`], the method for producing a copy of a value.
-//! * [`std::cmp`]::{[`PartialEq`], [`PartialOrd`], [`Eq`], [`Ord`]}: the
+//! * <code>[std::clone]::[Clone]</code>, the ubiquitous trait that defines
+//!   [`clone`][Clone::clone], the method for producing a copy of a value.
+//! * <code>[std::cmp]::{[PartialEq], [PartialOrd], [Eq], [Ord]}</code>, the
 //!   comparison traits, which implement the comparison operators and are often
 //!   seen in trait bounds.
-//! * [`std::convert`]::{[`AsRef`], [`AsMut`], [`Into`], [`From`]}: generic
+//! * <code>[std::convert]::{[AsRef], [AsMut], [Into], [From]}</code>, generic
 //!   conversions, used by savvy API authors to create overloaded methods.
-//! * [`std::default`]::[`Default`], types that have default values.
-//! * [`std::iter`]::{[`Iterator`], [`Extend`], [`IntoIterator`],
-//!   [`DoubleEndedIterator`], [`ExactSizeIterator`]}: iterators of various
+//! * <code>[std::default]::[Default]</code>, types that have default values.
+//! * <code>[std::iter]::{[Iterator], [Extend], [IntoIterator], [DoubleEndedIterator], [ExactSizeIterator]}</code>,
+//!   iterators of various
 //!   kinds.
-//! * [`std::option`]::[`Option`]::{[`self`][`Option`], [`Some`], [`None`]}, a
+//! * <code>[std::option]::[Option]::{[self][Option], [Some], [None]}</code>, a
 //!   type which expresses the presence or absence of a value. This type is so
 //!   commonly used, its variants are also exported.
-//! * [`std::result`]::[`Result`]::{[`self`][`Result`], [`Ok`], [`Err`]}: a type
+//! * <code>[std::result]::[Result]::{[self][Result], [Ok], [Err]}</code>, a type
 //!   for functions that may succeed or fail. Like [`Option`], its variants are
 //!   exported as well.
-//! * [`std::string`]::{[`String`], [`ToString`]}: heap-allocated strings.
-//! * [`std::vec`]::[`Vec`]: a growable, heap-allocated vector.
+//! * <code>[std::string]::{[String], [ToString]}</code>, heap-allocated strings.
+//! * <code>[std::vec]::[Vec]</code>, a growable, heap-allocated vector.
 //!
-//! [`mem::drop`]: crate::mem::drop
-//! [`std::borrow`]: crate::borrow
-//! [`std::boxed`]: crate::boxed
-//! [`std::clone`]: crate::clone
-//! [`std::cmp`]: crate::cmp
-//! [`std::convert`]: crate::convert
-//! [`std::default`]: crate::default
-//! [`std::iter`]: crate::iter
-//! [`std::marker`]: crate::marker
-//! [`std::mem`]: crate::mem
-//! [`std::ops`]: crate::ops
-//! [`std::option`]: crate::option
+//! [mem::drop]: crate::mem::drop
+//! [std::borrow]: crate::borrow
+//! [std::boxed]: crate::boxed
+//! [std::clone]: crate::clone
+//! [std::cmp]: crate::cmp
+//! [std::convert]: crate::convert
+//! [std::default]: crate::default
+//! [std::iter]: crate::iter
+//! [std::marker]: crate::marker
+//! [std::mem]: crate::mem
+//! [std::ops]: crate::ops
+//! [std::option]: crate::option
 //! [`std::prelude::v1`]: v1
-//! [`std::result`]: crate::result
-//! [`std::slice`]: crate::slice
-//! [`std::string`]: crate::string
-//! [`std::vec`]: mod@crate::vec
+//! [std::result]: crate::result
+//! [std::slice]: crate::slice
+//! [std::string]: crate::string
+//! [std::vec]: mod@crate::vec
 //! [`to_owned`]: crate::borrow::ToOwned::to_owned
 //! [book-closures]: ../../book/ch13-01-closures.html
 //! [book-dtor]: ../../book/ch15-03-drop.html

src/bootstrap/test.rs

@@ -108,6 +108,19 @@ impl Step for Linkcheck {
     /// documentation to ensure we don't have a bunch of dead ones.
     fn run(self, builder: &Builder<'_>) {
         let host = self.host;
+        let hosts = &builder.hosts;
+        let targets = &builder.targets;
+
+        // if we have different hosts and targets, some things may be built for
+        // the host (e.g. rustc) and others for the target (e.g. std). The
+        // documentation built for each will contain broken links to
+        // docs built for the other platform (e.g. rustc linking to cargo)
+        if (hosts != targets) && !hosts.is_empty() && !targets.is_empty() {
+            panic!(
+                "Linkcheck currently does not support builds with different hosts and targets.
+You can skip linkcheck with --exclude src/tools/linkchecker"
+            );
+        }
 
         builder.info(&format!("Linkcheck ({})", host));
 
@@ -123,19 +136,6 @@ impl Step for Linkcheck {
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
         let builder = run.builder;
         let run = run.path("src/tools/linkchecker");
-        let hosts = &builder.hosts;
-        let targets = &builder.targets;
-
-        // if we have different hosts and targets, some things may be built for
-        // the host (e.g. rustc) and others for the target (e.g. std). The
-        // documentation built for each will contain broken links to
-        // docs built for the other platform (e.g. rustc linking to cargo)
-        if (hosts != targets) && !hosts.is_empty() && !targets.is_empty() {
-            panic!(
-                "Linkcheck currently does not support builds with different hosts and targets.
-You can skip linkcheck with --exclude src/tools/linkchecker"
-            );
-        }
         run.default_condition(builder.config.docs)
     }
 

src/test/ui/inference/issue-83606.rs

@@ -0,0 +1,10 @@
+// Regression test for #83606.
+
+fn foo<const N: usize>(_: impl std::fmt::Display) -> [usize; N] {
+    [0; N]
+}
+
+fn main() {
+    let _ = foo("foo"); //<- Do not suggest `foo::<N>("foo");`!
+    //~^ ERROR: type annotations needed for `[usize; _]`
+}

src/test/ui/inference/issue-83606.stderr

@@ -0,0 +1,11 @@
+error[E0282]: type annotations needed for `[usize; _]`
+  --> $DIR/issue-83606.rs:8:13
+   |
+LL |     let _ = foo("foo"); //<- Do not suggest `foo::<N>("foo");`!
+   |         -   ^^^ cannot infer the value of const parameter `N` declared on the function `foo`
+   |         |
+   |         consider giving this pattern the explicit type `[usize; _]`, where the type parameter `N` is specified
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.

src/test/ui/proc-macro/auxiliary/issue-75801.rs

@@ -0,0 +1,13 @@
+// force-host
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+
+#[proc_macro_attribute]
+pub fn foo(_args: TokenStream, item: TokenStream) -> TokenStream {
+    item
+}

src/test/ui/proc-macro/issue-75801.rs

@@ -0,0 +1,19 @@
+// aux-build: issue-75801.rs
+
+// Regression test for #75801.
+
+#[macro_use]
+extern crate issue_75801;
+
+macro_rules! foo {
+    ($arg:expr) => {
+        #[foo]
+        fn bar() {
+            let _bar: u32 = $arg;
+        }
+    };
+}
+
+foo!("baz"); //~ ERROR: mismatched types [E0308]
+
+fn main() {}

src/test/ui/proc-macro/issue-75801.stderr

@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-75801.rs:17:6
+   |
+LL |             let _bar: u32 = $arg;
+   |                       --- expected due to this
+...
+LL | foo!("baz");
+   |      ^^^^^ expected `u32`, found `&str`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.