Auto merge of #58495 - kennytm:rollup, r=kennytm

Rollup of 19 pull requests

Successful merges:

 - #57929 (Rustdoc remove old style files)
 - #57981 (Fix #57730)
 - #58074 (Stabilize slice_sort_by_cached_key)
 - #58196 (Add specific feature gate error for const-unstable features)
 - #58293 (Remove code for updating copyright years in generate-deriving-span-tests)
 - #58306 (Don't default on std crate when manipulating browser history)
 - #58359 (librustc_mir: use ? in impl_snapshot_for! macro)
 - #58395 (Instant::checked_duration_since)
 - #58429 (fix Box::into_unique effecitvely transmuting to a raw ptr)
 - #58433 (Update which libcore/liballoc tests Miri ignores, and document why)
 - #58438 (Use posix_spawn_file_actions_addchdir_np when possible)
 - #58440 (Whitelist the ARM v6 target-feature)
 - #58448 (rustdoc: mask `compiler_builtins` docs)
 - #58468 (split MaybeUninit into several features, expand docs a bit)
 - #58479 (compile-pass test for #53606)
 - #58489 (Fix runtime error in generate-keyword-tests)
 - #58496 (Fix documentation for std::path::PathBuf::pop)
 - #58509 (Notify myself when Clippy toolstate changes)
 - #58521 (Fix tracking issue for error iterators)

Author: bors

src/bootstrap/bin/rustdoc.rs

@@ -16,6 +16,7 @@ fn main() {
     let libdir = env::var_os("RUSTDOC_LIBDIR").expect("RUSTDOC_LIBDIR was not set");
     let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
+    let mut has_unstable = false;
 
     use std::str::FromStr;
 
@@ -54,9 +55,22 @@ fn main() {
     // it up so we can make rustdoc print this into the docs
     if let Some(version) = env::var_os("RUSTDOC_CRATE_VERSION") {
         // This "unstable-options" can be removed when `--crate-version` is stabilized
-        cmd.arg("-Z")
-           .arg("unstable-options")
-           .arg("--crate-version").arg(version);
+        if !has_unstable {
+            cmd.arg("-Z")
+               .arg("unstable-options");
+        }
+        cmd.arg("--crate-version").arg(version);
+        has_unstable = true;
+    }
+
+    // Needed to be able to run all rustdoc tests.
+    if let Some(_) = env::var_os("RUSTDOC_GENERATE_REDIRECT_PAGES") {
+        // This "unstable-options" can be removed when `--generate-redirect-pages` is stabilized
+        if !has_unstable {
+            cmd.arg("-Z")
+               .arg("unstable-options");
+        }
+        cmd.arg("--generate-redirect-pages");
     }
 
     if verbose > 1 {

src/bootstrap/doc.rs

@@ -517,6 +517,7 @@ impl Step for Std {
             cargo.arg("--")
                  .arg("--markdown-css").arg("rust.css")
                  .arg("--markdown-no-toc")
+                 .arg("--generate-redirect-pages")
                  .arg("--index-page").arg(&builder.src.join("src/doc/index.md"));
 
             builder.run(&mut cargo);
@@ -581,7 +582,9 @@ impl Step for Test {
         let mut cargo = builder.cargo(compiler, Mode::Test, target, "doc");
         compile::test_cargo(builder, &compiler, target, &mut cargo);
 
-        cargo.arg("--no-deps").arg("-p").arg("test");
+        cargo.arg("--no-deps")
+             .arg("-p").arg("test")
+             .env("RUSTDOC_GENERATE_REDIRECT_PAGES", "1");
 
         builder.run(&mut cargo);
         builder.cp_r(&my_out, &out);
@@ -650,9 +653,9 @@ impl Step for WhitelistedRustc {
         // We don't want to build docs for internal compiler dependencies in this
         // step (there is another step for that). Therefore, we whitelist the crates
         // for which docs must be built.
-        cargo.arg("--no-deps");
         for krate in &["proc_macro"] {
-            cargo.arg("-p").arg(krate);
+            cargo.arg("-p").arg(krate)
+                 .env("RUSTDOC_GENERATE_REDIRECT_PAGES", "1");
         }
 
         builder.run(&mut cargo);

src/etc/generate-deriving-span-tests.py

@@ -8,14 +8,12 @@
 sample usage: src/etc/generate-deriving-span-tests.py
 """
 
-import os, datetime, stat, re
+import os, stat
 
 TEST_DIR = os.path.abspath(
     os.path.join(os.path.dirname(__file__), '../test/ui/derives/'))
 
-YEAR = datetime.datetime.now().year
-
-TEMPLATE = """
+TEMPLATE = """\
 // This file was auto-generated using 'src/etc/generate-deriving-span-tests.py'
 
 {error_deriving}
@@ -63,19 +61,11 @@ def create_test_case(type, trait, super_traits, error_count):
 
     errors = '\n'.join('//~%s ERROR' % ('^' * n) for n in range(error_count))
     code = string.format(traits = all_traits, errors = errors)
-    return TEMPLATE.format(year = YEAR, error_deriving=error_deriving, code = code)
+    return TEMPLATE.format(error_deriving=error_deriving, code = code)
 
 def write_file(name, string):
     test_file = os.path.join(TEST_DIR, 'derives-span-%s.rs' % name)
 
-    with open(test_file) as f:
-        old_str = f.read()
-        old_str_ignoring_date = re.sub(r'^// Copyright \d+',
-                                        '// Copyright {year}'.format(year = YEAR), old_str)
-        if old_str_ignoring_date == string:
-            # if all we're doing is updating the copyright year, ignore it
-            return 0
-
     # set write permission if file exists, so it can be changed
     if os.path.exists(test_file):
         os.chmod(test_file, stat.S_IWUSR)
@@ -86,8 +76,6 @@ def write_file(name, string):
     # mark file read-only
     os.chmod(test_file, stat.S_IRUSR|stat.S_IRGRP|stat.S_IROTH)
 
-    return 1
-
 
 ENUM = 1
 STRUCT = 2
@@ -110,15 +98,11 @@ def write_file(name, string):
                               ('Hash', [], 1)]:
     traits[trait] = (ALL, supers, errs)
 
-files = 0
-
 for (trait, (types, super_traits, error_count)) in traits.items():
     mk = lambda ty: create_test_case(ty, trait, super_traits, error_count)
     if types & ENUM:
-        files += write_file(trait + '-enum', mk(ENUM_TUPLE))
-        files += write_file(trait + '-enum-struct-variant', mk(ENUM_STRUCT))
+        write_file(trait + '-enum', mk(ENUM_TUPLE))
+        write_file(trait + '-enum-struct-variant', mk(ENUM_STRUCT))
     if types & STRUCT:
-        files += write_file(trait + '-struct', mk(STRUCT_FIELDS))
-        files += write_file(trait + '-tuple-struct', mk(STRUCT_TUPLE))
-
-print('Generated {files} deriving span test{}.'.format('s' if files != 1 else '', files = files))
+        write_file(trait + '-struct', mk(STRUCT_FIELDS))
+        write_file(trait + '-tuple-struct', mk(STRUCT_TUPLE))

src/etc/generate-keyword-tests.py

@@ -15,7 +15,7 @@
 import stat
 
 
-template = """
+template = """\
 // This file was auto-generated using 'src/etc/generate-keyword-tests.py %s'
 
 fn main() {
@@ -35,7 +35,7 @@
         os.chmod(test_file, stat.S_IWUSR)
 
     with open(test_file, 'wt') as f:
-        f.write(template % (datetime.datetime.now().year, kw, kw, kw))
+        f.write(template % (kw, kw, kw))
 
     # mark file read-only
     os.chmod(test_file, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)

src/liballoc/benches/lib.rs

@@ -1,5 +1,4 @@
 #![feature(repr_simd)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(test)]
 
 extern crate rand;

src/liballoc/boxed.rs

@@ -202,10 +202,15 @@ impl<T: ?Sized> Box<T> {
     #[unstable(feature = "ptr_internals", issue = "0", reason = "use into_raw_non_null instead")]
     #[inline]
     #[doc(hidden)]
-    pub fn into_unique(b: Box<T>) -> Unique<T> {
-        let unique = b.0;
+    pub fn into_unique(mut b: Box<T>) -> Unique<T> {
+        // Box is kind-of a library type, but recognized as a "unique pointer" by
+        // Stacked Borrows.  This function here corresponds to "reborrowing to
+        // a raw pointer", but there is no actual reborrow here -- so
+        // without some care, the pointer we are returning here still carries
+        // the `Uniq` tag.  We round-trip through a mutable reference to avoid that.
+        let unique = unsafe { b.0.as_mut() as *mut T };
         mem::forget(b);
-        unique
+        unsafe { Unique::new_unchecked(unique) }
     }
 
     /// Consumes and leaks the `Box`, returning a mutable reference,

src/liballoc/collections/btree/node.rs

@@ -453,7 +453,7 @@ impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> {
                     root: self.root,
                     _marker: PhantomData
                 },
-                idx: unsafe { usize::from(*self.as_header().parent_idx.get_ref()) },
+                idx: unsafe { usize::from(*self.as_header().parent_idx.as_ptr()) },
                 _marker: PhantomData
             })
         } else {
@@ -1143,7 +1143,7 @@ impl<BorrowType, K, V>
         NodeRef {
             height: self.node.height - 1,
             node: unsafe {
-                self.node.as_internal().edges.get_unchecked(self.idx).get_ref().as_ptr()
+                (&*self.node.as_internal().edges.get_unchecked(self.idx).as_ptr()).as_ptr()
             },
             root: self.node.root,
             _marker: PhantomData

src/liballoc/lib.rs

@@ -112,7 +112,7 @@
 #![feature(rustc_const_unstable)]
 #![feature(const_vec_new)]
 #![feature(slice_partition_dedup)]
-#![feature(maybe_uninit)]
+#![feature(maybe_uninit, maybe_uninit_slice, maybe_uninit_array)]
 #![feature(alloc_layout_extra)]
 #![feature(try_trait)]
 

src/liballoc/slice.rs

@@ -257,6 +257,10 @@ impl<T> [T] {
     /// This sort is stable (i.e., does not reorder equal elements) and `O(m n log(m n))`
     /// worst-case, where the key function is `O(m)`.
     ///
+    /// For expensive key functions (e.g. functions that are not simple property accesses or
+    /// basic operations), [`sort_by_cached_key`](#method.sort_by_cached_key) is likely to be
+    /// significantly faster, as it does not recompute element keys.
+    ///
     /// When applicable, unstable sorting is preferred because it is generally faster than stable
     /// sorting and it doesn't allocate auxiliary memory.
     /// See [`sort_unstable_by_key`](#method.sort_unstable_by_key).
@@ -312,15 +316,14 @@ impl<T> [T] {
     /// # Examples
     ///
     /// ```
-    /// #![feature(slice_sort_by_cached_key)]
     /// let mut v = [-5i32, 4, 32, -3, 2];
     ///
     /// v.sort_by_cached_key(|k| k.to_string());
     /// assert!(v == [-3, -5, 2, 32, 4]);
     /// ```
     ///
     /// [pdqsort]: https://github.com/orlp/pdqsort
-    #[unstable(feature = "slice_sort_by_cached_key", issue = "34447")]
+    #[stable(feature = "slice_sort_by_cached_key", since = "1.34.0")]
     #[inline]
     pub fn sort_by_cached_key<K, F>(&mut self, f: F)
         where F: FnMut(&T) -> K, K: Ord

src/liballoc/tests/arc.rs

@@ -1,5 +1,3 @@
-#![cfg(not(miri))]
-
 use std::any::Any;
 use std::sync::{Arc, Weak};
 use std::cell::RefCell;