Auto merge of #44058 - frewsxcv:rollup, r=frewsxcv

Rollup of 8 pull requests

- Successful merges: #43631, #43977, #43983, #44016, #44039, #44043, #44047, #44054
- Failed merges:

4 files changed, 21 insertions, 9 deletions

diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 880caa2ade5..30495f29745 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -81,7 +81,7 @@
 //! Note the documentation for the primitives [`str`] and [`[T]`][slice] (also
 //! called 'slice'). Many method calls on [`String`] and [`Vec<T>`] are actually
 //! calls to methods on [`str`] and [`[T]`][slice] respectively, via [deref
-//! coercions].
+//! coercions][deref-coercions].
 //!
 //! Third, the standard library defines [The Rust Prelude], a small collection
 //! of items - mostly traits - that are imported into every module of every
@@ -203,7 +203,7 @@
 //! [`use`]: ../book/first-edition/crates-and-modules.html#importing-modules-with-use
 //! [crate root]: ../book/first-edition/crates-and-modules.html#basic-terminology-crates-and-modules
 //! [crates.io]: https://crates.io
-//! [deref coercions]: ../book/first-edition/deref-coercions.html
+//! [deref-coercions]: ../book/second-edition/ch15-02-deref.html#implicit-deref-coercions-with-functions-and-methods
 //! [files]: fs/struct.File.html
 //! [multithreading]: thread/index.html
 //! [other]: #what-is-in-the-standard-library-documentation
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 680bb057858..830b9dc475d 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -323,6 +323,11 @@ unsafe fn u8_slice_as_os_str(s: &[u8]) -> &OsStr {
     mem::transmute(s)
 }
 
+// Detect scheme on Redox
+fn has_redox_scheme(s: &[u8]) -> bool {
+    cfg!(target_os = "redox") && s.split(|b| *b == b'/').next().unwrap_or(b"").contains(&b':')
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Cross-platform, iterator-independent parsing
 ////////////////////////////////////////////////////////////////////////////////
@@ -1685,8 +1690,12 @@ impl Path {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow(deprecated)]
     pub fn is_absolute(&self) -> bool {
-        // FIXME: Remove target_os = "redox" and allow Redox prefixes
-        self.has_root() && (cfg!(unix) || cfg!(target_os = "redox") || self.prefix().is_some())
+        if !cfg!(target_os = "redox") {
+            self.has_root() && (cfg!(unix) || self.prefix().is_some())
+        } else {
+            // FIXME: Allow Redox prefixes
+            has_redox_scheme(self.as_u8_slice())
+        }
     }
 
     /// Returns `true` if the `Path` is relative, i.e. not absolute.
@@ -2050,7 +2059,8 @@ impl Path {
         Components {
             path: self.as_u8_slice(),
             prefix,
-            has_physical_root: has_physical_root(self.as_u8_slice(), prefix),
+            has_physical_root: has_physical_root(self.as_u8_slice(), prefix) ||
+                               has_redox_scheme(self.as_u8_slice()),
             front: State::Prefix,
             back: State::Body,
         }
diff --git a/src/libstd/primitive_docs.rs b/src/libstd/primitive_docs.rs
index 6746754ebc3..76ef36cc9a7 100644
--- a/src/libstd/primitive_docs.rs
+++ b/src/libstd/primitive_docs.rs
@@ -188,9 +188,10 @@ mod prim_unit { }
 /// Working with raw pointers in Rust is uncommon,
 /// typically limited to a few patterns.
 ///
-/// Use the [`null`] function to create null pointers, and the [`is_null`] method
-/// of the `*const T` type  to check for null. The `*const T` type also defines
-/// the [`offset`] method, for pointer math.
+/// Use the [`null`] and [`null_mut`] functions to create null pointers, and the
+/// [`is_null`] method of the `*const T` and `*mut T` types to check for null.
+/// The `*const T` and `*mut T` types also define the [`offset`] method, for
+/// pointer math.
 ///
 /// # Common ways to create raw pointers
 ///
@@ -261,6 +262,7 @@ mod prim_unit { }
 /// *[See also the `std::ptr` module](ptr/index.html).*
 ///
 /// [`null`]: ../std/ptr/fn.null.html
+/// [`null_mut`]: ../std/ptr/fn.null_mut.html
 /// [`is_null`]: ../std/primitive.pointer.html#method.is_null
 /// [`offset`]: ../std/primitive.pointer.html#method.offset
 /// [`into_raw`]: ../std/boxed/struct.Box.html#method.into_raw
diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs
index 83feb595bce..ee103c803f5 100644
--- a/src/libstd/thread/mod.rs
+++ b/src/libstd/thread/mod.rs
@@ -374,7 +374,7 @@ impl Builder {
     {
         let Builder { name, stack_size } = self;
 
-        let stack_size = stack_size.unwrap_or(util::min_stack());
+        let stack_size = stack_size.unwrap_or_else(util::min_stack);
 
         let my_thread = Thread::new(name);
         let their_thread = my_thread.clone();