Auto merge of rust-lang#57542 - Centril:rollup, r=Centril

Rollup of 26 pull requests

Successful merges:

 - rust-lang#56425 (Redo the docs for Vec::set_len)
 - rust-lang#56906 (Issue rust-lang#56905)
 - rust-lang#57042 (Don't call `FieldPlacement::count` when count is too large)
 - rust-lang#57175 (Stabilize `let` bindings and destructuring in constants and const fn)
 - rust-lang#57192 (Change std::error::Error trait documentation to talk about `source` instead of `cause`)
 - rust-lang#57296 (Fixed the link to the ? operator)
 - rust-lang#57368 (Use CMAKE_{C,CXX}_COMPILER_LAUNCHER for ccache)
 - rust-lang#57400 (Rustdoc: update Source Serif Pro and replace Heuristica italic)
 - rust-lang#57417 (rustdoc: use text-based doctest parsing if a macro is wrapping main)
 - rust-lang#57433 (Add link destination for `read-ownership`)
 - rust-lang#57434 (Remove `CrateNum::Invalid`.)
 - rust-lang#57441 (Supporting backtrace for x86_64-fortanix-unknown-sgx.)
 - rust-lang#57450 (actually take a slice in this example)
 - rust-lang#57459 (Reference tracking issue for inherent associated types in diagnostic)
 - rust-lang#57463 (docs: Fix some 'second-edition' links)
 - rust-lang#57466 (Remove outdated comment)
 - rust-lang#57493 (use structured suggestion when casting a reference)
 - rust-lang#57498 (make note of one more normalization that Paths do)
 - rust-lang#57499 (note that FromStr does not work for borrowed types)
 - rust-lang#57505 (Remove submodule step from README)
 - rust-lang#57510 (Add a profiles section to the manifest)
 - rust-lang#57511 (Fix undefined behavior)
 - rust-lang#57519 (Correct RELEASES.md for 1.32.0)
 - rust-lang#57522 (don't unwrap unexpected tokens in `format!`)
 - rust-lang#57530 (Fixing a typographical error.)
 - rust-lang#57535 (Stabilise irrefutable if-let and while-let patterns)

Failed merges:

r? @ghost

Author: bors

README.md

@@ -38,7 +38,6 @@ Read ["Installation"] from [The Book].
 3. Build and install:
 
     ```sh
-    $ git submodule update --init --recursive --progress
     $ ./x.py build && sudo ./x.py install
     ```
 

RELEASES.md

@@ -121,6 +121,12 @@ Stabilized APIs
 - [`i64::from_be_bytes`]
 - [`i64::from_le_bytes`]
 - [`i64::from_ne_bytes`]
+- [`i128::to_be_bytes`]
+- [`i128::to_le_bytes`]
+- [`i128::to_ne_bytes`]
+- [`i128::from_be_bytes`]
+- [`i128::from_le_bytes`]
+- [`i128::from_ne_bytes`]
 - [`isize::to_be_bytes`]
 - [`isize::to_le_bytes`]
 - [`isize::to_ne_bytes`]
@@ -151,6 +157,12 @@ Stabilized APIs
 - [`u64::from_be_bytes`]
 - [`u64::from_le_bytes`]
 - [`u64::from_ne_bytes`]
+- [`u128::to_be_bytes`]
+- [`u128::to_le_bytes`]
+- [`u128::to_ne_bytes`]
+- [`u128::from_be_bytes`]
+- [`u128::from_le_bytes`]
+- [`u128::from_ne_bytes`]
 - [`usize::to_be_bytes`]
 - [`usize::to_le_bytes`]
 - [`usize::to_ne_bytes`]
@@ -208,6 +220,12 @@ Compatibility Notes
 [`UnsafeCell::get`]: https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.get
 [`slice::as_ptr`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr
 [`char::is_ascii`]: https://doc.rust-lang.org/std/primitive.char.html#method.is_ascii
+[`i128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_be_bytes
+[`i128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_le_bytes
+[`i128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_ne_bytes
+[`i128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_be_bytes
+[`i128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_le_bytes
+[`i128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_ne_bytes
 [`i16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_be_bytes
 [`i16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_le_bytes
 [`i16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_ne_bytes
@@ -240,6 +258,12 @@ Compatibility Notes
 [`isize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_ne_bytes
 [`iter::empty`]: https://doc.rust-lang.org/std/iter/fn.empty.html
 [`str::as_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_ptr
+[`u128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_be_bytes
+[`u128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_le_bytes
+[`u128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_ne_bytes
+[`u128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_be_bytes
+[`u128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_le_bytes
+[`u128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_ne_bytes
 [`u16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_be_bytes
 [`u16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_le_bytes
 [`u16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_ne_bytes

config.toml.example

@@ -288,7 +288,7 @@
 #codegen-units-std = 1
 
 # Whether or not debug assertions are enabled for the compiler and standard
-# library. Also enables compilation of debug! and trace! logging macros.
+# library.
 #debug-assertions = false
 
 # Whether or not debuginfo is emitted

src/bootstrap/native.rs

@@ -346,15 +346,13 @@ fn configure_cmake(builder: &Builder,
        if builder.config.llvm_clang_cl.is_some() && target.contains("i686") {
            cfg.env("SCCACHE_EXTRA_ARGS", "-m32");
        }
-
-    // If ccache is configured we inform the build a little differently how
-    // to invoke ccache while also invoking our compilers.
-    } else if let Some(ref ccache) = builder.config.ccache {
-       cfg.define("CMAKE_C_COMPILER", ccache)
-          .define("CMAKE_C_COMPILER_ARG1", sanitize_cc(cc))
-          .define("CMAKE_CXX_COMPILER", ccache)
-          .define("CMAKE_CXX_COMPILER_ARG1", sanitize_cc(cxx));
     } else {
+       // If ccache is configured we inform the build a little differently how
+       // to invoke ccache while also invoking our compilers.
+       if let Some(ref ccache) = builder.config.ccache {
+         cfg.define("CMAKE_C_COMPILER_LAUNCHER", ccache)
+            .define("CMAKE_CXX_COMPILER_LAUNCHER", ccache);
+       }
        cfg.define("CMAKE_C_COMPILER", sanitize_cc(cc))
           .define("CMAKE_CXX_COMPILER", sanitize_cc(cxx));
     }

src/doc/unstable-book/src/language-features/irrefutable-let-patterns.md

@@ -738,53 +738,88 @@ impl<T> Vec<T> {
         self
     }
 
-    /// Sets the length of a vector.
+    /// Forces the length of the vector to `new_len`.
     ///
-    /// This will explicitly set the size of the vector, without actually
-    /// modifying its buffers, so it is up to the caller to ensure that the
-    /// vector is actually the specified size.
+    /// This is a low-level operation that maintains none of the normal
+    /// invariants of the type.  Normally changing the length of a vector
+    /// is done using one of the safe operations instead, such as
+    /// [`truncate`], [`resize`], [`extend`], or [`clear`].
     ///
-    /// # Examples
+    /// [`truncate`]: #method.truncate
+    /// [`resize`]: #method.resize
+    /// [`extend`]: #method.extend-1
+    /// [`clear`]: #method.clear
     ///
-    /// ```
-    /// use std::ptr;
+    /// # Safety
     ///
-    /// let mut vec = vec!['r', 'u', 's', 't'];
+    /// - `new_len` must be less than or equal to [`capacity()`].
+    /// - The elements at `old_len..new_len` must be initialized.
     ///
-    /// unsafe {
-    ///     ptr::drop_in_place(&mut vec[3]);
-    ///     vec.set_len(3);
+    /// [`capacity()`]: #method.capacity
+    ///
+    /// # Examples
+    ///
+    /// This method can be useful for situations in which the vector
+    /// is serving as a buffer for other code, particularly over FFI:
+    ///
+    /// ```no_run
+    /// # #![allow(dead_code)]
+    /// # // This is just a minimal skeleton for the doc example;
+    /// # // don't use this as a starting point for a real library.
+    /// # pub struct StreamWrapper { strm: *mut std::ffi::c_void }
+    /// # const Z_OK: i32 = 0;
+    /// # extern "C" {
+    /// #     fn deflateGetDictionary(
+    /// #         strm: *mut std::ffi::c_void,
+    /// #         dictionary: *mut u8,
+    /// #         dictLength: *mut usize,
+    /// #     ) -> i32;
+    /// # }
+    /// # impl StreamWrapper {
+    /// pub fn get_dictionary(&self) -> Option<Vec<u8>> {
+    ///     // Per the FFI method's docs, "32768 bytes is always enough".
+    ///     let mut dict = Vec::with_capacity(32_768);
+    ///     let mut dict_length = 0;
+    ///     // SAFETY: When `deflateGetDictionary` returns `Z_OK`, it holds that:
+    ///     // 1. `dict_length` elements were initialized.
+    ///     // 2. `dict_length` <= the capacity (32_768)
+    ///     // which makes `set_len` safe to call.
+    ///     unsafe {
+    ///         // Make the FFI call...
+    ///         let r = deflateGetDictionary(self.strm, dict.as_mut_ptr(), &mut dict_length);
+    ///         if r == Z_OK {
+    ///             // ...and update the length to what was initialized.
+    ///             dict.set_len(dict_length);
+    ///             Some(dict)
+    ///         } else {
+    ///             None
+    ///         }
+    ///     }
     /// }
-    /// assert_eq!(vec, ['r', 'u', 's']);
+    /// # }
     /// ```
     ///
-    /// In this example, there is a memory leak since the memory locations
-    /// owned by the inner vectors were not freed prior to the `set_len` call:
+    /// While the following example is sound, there is a memory leak since
+    /// the inner vectors were not freed prior to the `set_len` call:
     ///
     /// ```
     /// let mut vec = vec![vec![1, 0, 0],
     ///                    vec![0, 1, 0],
     ///                    vec![0, 0, 1]];
+    /// // SAFETY:
+    /// // 1. `old_len..0` is empty so no elements need to be initialized.
+    /// // 2. `0 <= capacity` always holds whatever `capacity` is.
     /// unsafe {
     ///     vec.set_len(0);
     /// }
     /// ```
     ///
-    /// In this example, the vector gets expanded from zero to four items
-    /// without any memory allocations occurring, resulting in vector
-    /// values of unallocated memory:
-    ///
-    /// ```
-    /// let mut vec: Vec<char> = Vec::new();
-    ///
-    /// unsafe {
-    ///     vec.set_len(4);
-    /// }
-    /// ```
+    /// Normally, here, one would use [`clear`] instead to correctly drop
+    /// the contents and thus not leak memory.
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub unsafe fn set_len(&mut self, len: usize) {
-        self.len = len;
+    pub unsafe fn set_len(&mut self, new_len: usize) {
+        self.len = new_len;
     }
 
     /// Removes an element from the vector and returns it.

src/liballoc/vec.rs

@@ -849,6 +849,7 @@ pub unsafe fn write_unaligned<T>(dst: *mut T, src: T) {
 /// [valid]: ../ptr/index.html#safety
 /// [`Copy`]: ../marker/trait.Copy.html
 /// [`read`]: ./fn.read.html
+/// [read-ownership]: ./fn.read.html#ownership-of-the-returned-value
 ///
 /// Just like in C, whether an operation is volatile has no bearing whatsoever
 /// on questions involving concurrent access from multiple threads. Volatile

src/libcore/ptr.rs

@@ -20,8 +20,7 @@ pub mod pattern;
 #[allow(missing_docs)]
 pub mod lossy;
 
-/// A trait to abstract the idea of creating a new instance of a type from a
-/// string.
+/// Parse a value from a string
 ///
 /// `FromStr`'s [`from_str`] method is often used implicitly, through
 /// [`str`]'s [`parse`] method. See [`parse`]'s documentation for examples.
@@ -30,6 +29,11 @@ pub mod lossy;
 /// [`str`]: ../../std/primitive.str.html
 /// [`parse`]: ../../std/primitive.str.html#method.parse
 ///
+/// `FromStr` does not have a lifetime parameter, and so you can only parse types
+/// that do not contain a lifetime parameter themselves. In other words, you can
+/// parse an `i32` with `FromStr`, but not a `&i32`. You can parse a struct that
+/// contains an `i32`, but not one that contains an `&i32`.
+///
 /// # Examples
 ///
 /// Basic implementation of `FromStr` on an example `Point` type:

src/libcore/str/mod.rs

@@ -17,8 +17,6 @@ pub enum CrateNum {
     // FIXME(jseyfried): this is also used for custom derives until proc-macro crates get
     // `CrateNum`s.
     BuiltinMacros,
-    /// A CrateNum value that indicates that something is wrong.
-    Invalid,
     /// A special CrateNum that we use for the tcx.rcache when decoding from
     /// the incr. comp. cache.
     ReservedForIncrCompCache,
@@ -29,7 +27,6 @@ impl ::std::fmt::Debug for CrateNum {
     fn fmt(&self, fmt: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
         match self {
             CrateNum::Index(id) => write!(fmt, "crate{}", id.private),
-            CrateNum::Invalid => write!(fmt, "invalid crate"),
             CrateNum::BuiltinMacros => write!(fmt, "builtin macros crate"),
             CrateNum::ReservedForIncrCompCache => write!(fmt, "crate for decoding incr comp cache"),
         }
@@ -90,7 +87,6 @@ impl fmt::Display for CrateNum {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             CrateNum::Index(id) => fmt::Display::fmt(&id.private, f),
-            CrateNum::Invalid => write!(f, "invalid crate"),
             CrateNum::BuiltinMacros => write!(f, "builtin macros crate"),
             CrateNum::ReservedForIncrCompCache => write!(f, "crate for decoding incr comp cache"),
         }

src/librustc/hir/def_id.rs

@@ -286,7 +286,7 @@ declare_lint! {
 
 declare_lint! {
     pub IRREFUTABLE_LET_PATTERNS,
-    Deny,
+    Warn,
     "detects irrefutable patterns in if-let and while-let statements"
 }