Auto merge of #56846 - pietroalbini:rollup, r=pietroalbini

Rollup of 7 pull requests

Successful merges:

 - #56677 (#[must_use] on traits in stdlib)
 - #56679 (overhaul external doc attribute diagnostics)
 - #56682 (Update the stdsimd submodule)
 - #56691 (fix install broken link)
 - #56710 (Always set the RDRAND and RDSEED features on SGX)
 - #56713 (Test capacity of ZST vector)
 - #56841 (Add some unit tests to compiletest)

Failed merges:

r? @ghost

Author: bors

README.md

@@ -10,7 +10,7 @@ standard library, and documentation.
 
 Read ["Installation"] from [The Book].
 
-["Installation"]: https://doc.rust-lang.org/book/second-edition/ch01-01-installation.html
+["Installation"]: https://doc.rust-lang.org/book/ch01-01-installation.html
 [The Book]: https://doc.rust-lang.org/book/index.html
 
 ## Building from Source

src/liballoc/tests/vec.rs

@@ -79,6 +79,11 @@ fn test_reserve() {
     assert!(v.capacity() >= 33)
 }
 
+#[test]
+fn test_zst_capacity() {
+    assert_eq!(Vec::<()>::new().capacity(), usize::max_value());
+}
+
 #[test]
 fn test_extend() {
     let mut v = Vec::new();

src/libcore/future/future.rs

@@ -33,6 +33,7 @@ use task::{Poll, LocalWaker};
 ///
 /// When using a future, you generally won't call `poll` directly, but instead
 /// `await!` the value.
+#[must_use]
 pub trait Future {
     /// The result of the `Future`.
     type Output;

src/libcore/iter/iterator.rs

@@ -98,6 +98,7 @@ fn _assert_is_object_safe(_: &dyn Iterator<Item=()>) {}
     message="`{Self}` is not an iterator"
 )]
 #[doc(spotlight)]
+#[must_use]
 pub trait Iterator {
     /// The type of the elements being iterated over.
     #[stable(feature = "rust1", since = "1.0.0")]

src/libcore/ops/function.rs

@@ -72,6 +72,7 @@
     label="expected an `Fn<{Args}>` closure, found `{Self}`",
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
+#[must_use]
 pub trait Fn<Args> : FnMut<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
@@ -150,6 +151,7 @@ pub trait Fn<Args> : FnMut<Args> {
     label="expected an `FnMut<{Args}>` closure, found `{Self}`",
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
+#[must_use]
 pub trait FnMut<Args> : FnOnce<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
@@ -228,6 +230,7 @@ pub trait FnMut<Args> : FnOnce<Args> {
     label="expected an `FnOnce<{Args}>` closure, found `{Self}`",
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
+#[must_use]
 pub trait FnOnce<Args> {
     /// The returned type after the call operator is used.
     #[stable(feature = "fn_once_output", since = "1.12.0")]

src/librustc_target/spec/x86_64_fortanix_unknown_sgx.rs

@@ -49,6 +49,7 @@ pub fn target() -> Result<Target, String> {
         max_atomic_width: Some(64),
         panic_strategy: PanicStrategy::Abort,
         cpu: "x86-64".into(),
+        features: "+rdrnd,+rdseed".into(),
         position_independent_executables: true,
         pre_link_args: iter::once(
                 (LinkerFlavor::Gcc, PRE_LINK_ARGS.iter().cloned().map(String::from).collect())

src/libsyntax/ext/expand.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use ast::{self, Block, Ident, NodeId, PatKind, Path};
+use ast::{self, Block, Ident, LitKind, NodeId, PatKind, Path};
 use ast::{MacStmtStyle, StmtKind, ItemKind};
 use attr::{self, HasAttrs};
 use source_map::{ExpnInfo, MacroBang, MacroAttribute, dummy_spanned, respan};
@@ -1535,21 +1535,65 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                             let item = attr::mk_list_item(DUMMY_SP, include_ident, include_info);
                             items.push(dummy_spanned(ast::NestedMetaItemKind::MetaItem(item)));
                         }
-                        Err(ref e) if e.kind() == ErrorKind::InvalidData => {
-                            self.cx.span_err(
-                                at.span,
-                                &format!("{} wasn't a utf-8 file", filename.display()),
-                            );
-                        }
                         Err(e) => {
-                            self.cx.span_err(
-                                at.span,
-                                &format!("couldn't read {}: {}", filename.display(), e),
-                            );
+                            let lit = it
+                                .meta_item()
+                                .and_then(|item| item.name_value_literal())
+                                .unwrap();
+
+                            if e.kind() == ErrorKind::InvalidData {
+                                self.cx
+                                    .struct_span_err(
+                                        lit.span,
+                                        &format!("{} wasn't a utf-8 file", filename.display()),
+                                    )
+                                    .span_label(lit.span, "contains invalid utf-8")
+                                    .emit();
+                            } else {
+                                let mut err = self.cx.struct_span_err(
+                                    lit.span,
+                                    &format!("couldn't read {}: {}", filename.display(), e),
+                                );
+                                err.span_label(lit.span, "couldn't read file");
+
+                                if e.kind() == ErrorKind::NotFound {
+                                    err.help("external doc paths are relative to the crate root");
+                                }
+
+                                err.emit();
+                            }
                         }
                     }
                 } else {
-                    items.push(noop_fold_meta_list_item(it, self));
+                    let mut err = self.cx.struct_span_err(
+                        it.span,
+                        &format!("expected path to external documentation"),
+                    );
+
+                    // Check if the user erroneously used `doc(include(...))` syntax.
+                    let literal = it.meta_item_list().and_then(|list| {
+                        if list.len() == 1 {
+                            list[0].literal().map(|literal| &literal.node)
+                        } else {
+                            None
+                        }
+                    });
+
+                    let (path, applicability) = match &literal {
+                        Some(LitKind::Str(path, ..)) => {
+                            (path.to_string(), Applicability::MachineApplicable)
+                        }
+                        _ => (String::from("<path>"), Applicability::HasPlaceholders),
+                    };
+
+                    err.span_suggestion_with_applicability(
+                        it.span,
+                        "provide a file path with `=`",
+                        format!("include = \"{}\"", path),
+                        applicability,
+                    );
+
+                    err.emit();
                 }
             }
 

src/stdsimd

@@ -0,0 +1,47 @@
+#![deny(unused_must_use)]
+#![feature(futures_api, pin, arbitrary_self_types)]
+
+use std::iter::Iterator;
+use std::future::Future;
+
+use std::task::{Poll, LocalWaker};
+use std::pin::Pin;
+use std::unimplemented;
+
+struct MyFuture;
+
+impl Future for MyFuture {
+   type Output = u32;
+
+   fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<u32> {
+      Poll::Pending
+   }
+}
+
+fn iterator() -> impl Iterator {
+   std::iter::empty::<u32>()
+}
+
+fn future() -> impl Future {
+   MyFuture
+}
+
+fn square_fn_once() -> impl FnOnce(u32) -> u32 {
+   |x| x * x
+}
+
+fn square_fn_mut() -> impl FnMut(u32) -> u32 {
+   |x| x * x
+}
+
+fn square_fn() -> impl Fn(u32) -> u32 {
+   |x| x * x
+}
+
+fn main() {
+   iterator(); //~ ERROR unused implementer of `std::iter::Iterator` that must be used
+   future(); //~ ERROR unused implementer of `std::future::Future` that must be used
+   square_fn_once(); //~ ERROR unused implementer of `std::ops::FnOnce` that must be used
+   square_fn_mut(); //~ ERROR unused implementer of `std::ops::FnMut` that must be used
+   square_fn(); //~ ERROR unused implementer of `std::ops::Fn` that must be used
+}

src/test/compile-fail/must_use-in-stdlib-traits.rs

@@ -0,0 +1 @@
+�(