Auto merge of #54021 - kennytm:rollup, r=kennytm

Rollup of 17 pull requests

Successful merges:

 - #53299 (Updated core/macros.rs to note it works in a no_std environment.)
 - #53376 (Cross reference io::copy and fs::copy in docs.)
 - #53455 (Individual docs for {from,to}_*_bytes)
 - #53550 (librustc_lint: In recursion warning, change 'recurring' to 'recursing')
 - #53860 (Migrate (some) of run-pass/ to ui)
 - #53874 (Implement Unpin for Box, Rc, and Arc)
 - #53895 (tidy: Cleanups and clippy warning fixes)
 - #53946 (Clarify `ManuallyDrop` docs)
 - #53948 (Minimized clippy test from when NLL disabled two-phase borrows)
 - #53959 (Add .git extension to submodule paths missing it)
 - #53966 (A few cleanups and minor improvements to mir/dataflow)
 - #53967 (propagate build.python into cmake)
 - #53979 (Remove `#[repr(transparent)]` from atomics)
 - #53991 (Add unchecked_shl/shr check for intrinsics to fix miri's test suit)
 - #53992 (migrate run-pass/borrowck to ui/run-pass)
 - #53994 (migrate run-pass/*/ to ui/run-pass)
 - #54023 (update clippy submodule)

Author: bors

.gitmodules

@@ -28,7 +28,7 @@
 	url = https://github.com/rust-lang-nursery/rls.git
 [submodule "src/libcompiler_builtins"]
 	path = src/libcompiler_builtins
-	url = https://github.com/rust-lang-nursery/compiler-builtins
+	url = https://github.com/rust-lang-nursery/compiler-builtins.git
 [submodule "src/tools/clippy"]
 	path = src/tools/clippy
 	url = https://github.com/rust-lang-nursery/rust-clippy.git
@@ -43,24 +43,25 @@
 	url = https://github.com/alexcrichton/dlmalloc-rs.git
 [submodule "src/doc/rust-by-example"]
 	path = src/doc/rust-by-example
-	url = https://github.com/rust-lang/rust-by-example
+	url = https://github.com/rust-lang/rust-by-example.git
 [submodule "src/llvm-emscripten"]
 	path = src/llvm-emscripten
-	url = https://github.com/rust-lang/llvm
+	url = https://github.com/rust-lang/llvm.git
 [submodule "src/stdsimd"]
 	path = src/stdsimd
-	url = https://github.com/rust-lang-nursery/stdsimd
+	url = https://github.com/rust-lang-nursery/stdsimd.git
 [submodule "src/tools/lld"]
 	path = src/tools/lld
 	url = https://github.com/rust-lang/lld.git
 [submodule "src/libbacktrace"]
 	path = src/libbacktrace
-	url = https://github.com/rust-lang-nursery/libbacktrace
+	url = https://github.com/rust-lang-nursery/libbacktrace.git
 [submodule "src/tools/lldb"]
 	path = src/tools/lldb
-	url = https://github.com/rust-lang-nursery/lldb/
+	url = https://github.com/rust-lang-nursery/lldb.git
 	branch = rust-release-80-v1
 [submodule "src/tools/clang"]
 	path = src/tools/clang
-	url = https://github.com/rust-lang-nursery/clang/
+	url = https://github.com/rust-lang-nursery/clang.git
 	branch = rust-release-80-v1
+  

src/Cargo.lock

@@ -296,12 +296,14 @@ version = "0.0.212"
 dependencies = [
  "cargo_metadata 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "clippy-mini-macro-test 0.2.0",
+ "clippy_dev 0.0.1",
  "clippy_lints 0.0.212",
  "compiletest_rs 0.3.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "derive-new 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-workspace-hack 1.0.0",
+ "rustc_tools_util 0.1.0",
  "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.75 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.75 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -311,6 +313,16 @@ dependencies = [
 name = "clippy-mini-macro-test"
 version = "0.2.0"
 
+[[package]]
+name = "clippy_dev"
+version = "0.0.1"
+dependencies = [
+ "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "clippy_lints"
 version = "0.0.212"
@@ -2361,6 +2373,10 @@ dependencies = [
  "serialize 0.0.0",
 ]
 
+[[package]]
+name = "rustc_tools_util"
+version = "0.1.0"
+
 [[package]]
 name = "rustc_traits"
 version = "0.0.0"

src/bootstrap/native.rs

@@ -239,6 +239,10 @@ impl Step for Llvm {
             cfg.define("LLVM_NATIVE_BUILD", builder.llvm_out(builder.config.build).join("build"));
         }
 
+        if let Some(ref python) = builder.config.python {
+            cfg.define("PYTHON_EXECUTABLE", python);
+        }
+
         configure_cmake(builder, target, &mut cfg, false);
 
         // FIXME: we don't actually need to build all LLVM tools and all LLVM

src/doc/rustc/src/lints/listing/warn-by-default.md

@@ -603,11 +603,11 @@ fn foo() {
 This will produce:
 
 ```text
-warning: function cannot return without recurring
+warning: function cannot return without recursing
  --> src/main.rs:1:1
   |
 1 | fn foo() {
-  | ^^^^^^^^ cannot return without recurring
+  | ^^^^^^^^ cannot return without recursing
 2 |     foo();
   |     ----- recursive call site
   |

src/liballoc/boxed.rs

@@ -749,6 +749,31 @@ impl<T: ?Sized> AsMut<T> for Box<T> {
     }
 }
 
+/* Nota bene
+ *
+ *  We could have chosen not to add this impl, and instead have written a
+ *  function of Pin<Box<T>> to Pin<T>. Such a function would not be sound,
+ *  because Box<T> implements Unpin even when T does not, as a result of
+ *  this impl.
+ *
+ *  We chose this API instead of the alternative for a few reasons:
+ *      - Logically, it is helpful to understand pinning in regard to the
+ *        memory region being pointed to. For this reason none of the
+ *        standard library pointer types support projecting through a pin
+ *        (Box<T> is the only pointer type in std for which this would be
+ *        safe.)
+ *      - It is in practice very useful to have Box<T> be unconditionally
+ *        Unpin because of trait objects, for which the structural auto
+ *        trait functionality does not apply (e.g. Box<dyn Foo> would
+ *        otherwise not be Unpin).
+ *
+ *  Another type with the same semantics as Box but only a conditional
+ *  implementation of `Unpin` (where `T: Unpin`) would be valid/safe, and
+ *  could have a method to project a Pin<T> from it.
+ */
+#[unstable(feature = "pin", issue = "49150")]
+impl<T: ?Sized> Unpin for Box<T> { }
+
 #[unstable(feature = "generator_trait", issue = "43122")]
 impl<T> Generator for Box<T>
     where T: Generator + ?Sized

src/liballoc/rc.rs

@@ -252,7 +252,7 @@ use core::fmt;
 use core::hash::{Hash, Hasher};
 use core::intrinsics::abort;
 use core::marker;
-use core::marker::{Unsize, PhantomData};
+use core::marker::{Unpin, Unsize, PhantomData};
 use core::mem::{self, align_of_val, forget, size_of_val};
 use core::ops::Deref;
 use core::ops::CoerceUnsized;
@@ -1830,3 +1830,6 @@ impl<T: ?Sized> AsRef<T> for Rc<T> {
         &**self
     }
 }
+
+#[unstable(feature = "pin", issue = "49150")]
+impl<T: ?Sized> Unpin for Rc<T> { }

src/liballoc/sync.rs

@@ -27,7 +27,7 @@ use core::mem::{self, align_of_val, size_of_val};
 use core::ops::Deref;
 use core::ops::CoerceUnsized;
 use core::ptr::{self, NonNull};
-use core::marker::{Unsize, PhantomData};
+use core::marker::{Unpin, Unsize, PhantomData};
 use core::hash::{Hash, Hasher};
 use core::{isize, usize};
 use core::convert::From;
@@ -1943,3 +1943,6 @@ impl<T: ?Sized> AsRef<T> for Arc<T> {
         &**self
     }
 }
+
+#[unstable(feature = "pin", issue = "49150")]
+impl<T: ?Sized> Unpin for Arc<T> { }

src/libcore/macros.rs

@@ -349,6 +349,26 @@ macro_rules! try {
 /// write!(&mut v, "s = {:?}", s).unwrap(); // uses io::Write::write_fmt
 /// assert_eq!(v, b"s = \"abc 123\"");
 /// ```
+///
+/// Note: This macro can be used in `no_std` setups as well
+/// In a `no_std` setup you are responsible for the
+/// implementation details of the components.
+///
+/// ```no_run
+/// # extern crate core;
+/// use core::fmt::Write;
+///
+/// struct Example;
+///
+/// impl Write for Example {
+///     fn write_str(&mut self, _s: &str) -> core::fmt::Result {
+///          unimplemented!();
+///     }
+/// }
+///
+/// let mut m = Example{};
+/// write!(&mut m, "Hello World").expect("Not written");
+/// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! write {

src/libcore/mem.rs

@@ -971,14 +971,16 @@ impl<T> ManuallyDrop<T> {
         ManuallyDrop { value }
     }
 
-    /// Extract the value from the ManuallyDrop container.
+    /// Extract the value from the `ManuallyDrop` container.
+    ///
+    /// This allows the value to be dropped again.
     ///
     /// # Examples
     ///
     /// ```rust
     /// use std::mem::ManuallyDrop;
     /// let x = ManuallyDrop::new(Box::new(()));
-    /// let _: Box<()> = ManuallyDrop::into_inner(x);
+    /// let _: Box<()> = ManuallyDrop::into_inner(x); // This drops the `Box`.
     /// ```
     #[stable(feature = "manually_drop", since = "1.20.0")]
     #[inline]
@@ -990,11 +992,15 @@ impl<T> ManuallyDrop<T> {
 impl<T: ?Sized> ManuallyDrop<T> {
     /// Manually drops the contained value.
     ///
+    /// If you have ownership of the value, you can use [`ManuallyDrop::into_inner`] instead.
+    ///
     /// # Safety
     ///
     /// This function runs the destructor of the contained value and thus the wrapped value
     /// now represents uninitialized data. It is up to the user of this method to ensure the
     /// uninitialized data is not actually used.
+    ///
+    /// [`ManuallyDrop::into_inner`]: #method.into_inner
     #[stable(feature = "manually_drop", since = "1.20.0")]
     #[inline]
     pub unsafe fn drop(slot: &mut ManuallyDrop<T>) {