---

yaml
---
r: 232631
b: refs/heads/try
c: e617a17
h: refs/heads/master
i:
  232629: a5cc99f
  232627: 10ae3a7
  232623: c88f92c
v: v3

Author: bors

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: edeb4f1c86cbf6af8ef9874d4b3af50f721ea1b8
 refs/heads/snap-stage3: 1af31d4974e33027a68126fa5a5a3c2c6491824f
-refs/heads/try: 90ed188c148181434e1055b9256107917a0c98eb
+refs/heads/try: e617a17369ef403268adcebc5e3e32a0bb5cf04c
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try/README.md

@@ -82,6 +82,28 @@ Read ["Installing Rust"] from [The Book].
    $ make && make install
    ```
 
+## Building Documentation
+
+If you’d like to build the documentation, it’s almost the same:
+
+```sh
+./configure
+$ make docs
+```
+
+Building the documentation requires building the compiler, so the above
+details will apply. Once you have the compiler built, you can
+
+```sh
+$ make docs NO_REBUILD=1 
+```
+
+To make sure you don’t re-build the compiler because you made a change
+to some documentation.
+
+The generated documentation will appear in a top-level `doc` directory,
+created by the `make` rule.
+
 ## Notes
 
 Since the Rust compiler is written in Rust, it must be built by a

branches/try/configure

@@ -607,6 +607,10 @@ valopt aarch64-linux-android-ndk "" "aarch64-linux-android NDK standalone path"
 valopt release-channel "dev" "the name of the release channel to build"
 valopt musl-root "/usr/local" "MUSL root installation directory"
 
+# Used on systems where "cc" and "ar" are unavailable
+valopt default-linker "cc" "the default linker"
+valopt default-ar     "ar" "the default ar"
+
 # Many of these are saved below during the "writing configuration" step
 # (others are conditionally saved).
 opt_nosave manage-submodules 1 "let the build manage the git submodules"

branches/try/man/rustc.1

@@ -41,7 +41,7 @@ look for anything here (the default)
 .RE
 .TP
 \fB\-l\fR [\fIKIND\fR=]\fINAME\fR
-Link the generated crate(s) to the specified native library \fINAME\fR.
+Link the generated crate(s) to the specified library \fINAME\fR.
 The optional \fIKIND\fR can be one of \fIstatic\fR, \fIdylib\fR, or
 \fIframework\fR.
 If omitted, \fIdylib\fR is assumed.
@@ -113,7 +113,8 @@ Print version info and exit.
 Use verbose output.
 .TP
 \fB\-\-extern\fR \fINAME\fR=\fIPATH\fR
-Specify where an external rust library is located.
+Specify where an external rust library is located. These should match
+\fIextern\fR declarations in the crate's source code.
 .TP
 \fB\-\-sysroot\fR \fIPATH\fR
 Override the system root.

branches/try/mk/crates.mk

@@ -56,7 +56,7 @@ TARGET_CRATES := libc std flate arena term \
 		 alloc_system
 RUSTC_CRATES := rustc rustc_typeck rustc_borrowck rustc_resolve rustc_driver \
                 rustc_trans rustc_back rustc_llvm rustc_privacy rustc_lint \
-                rustc_data_structures
+                rustc_data_structures rustc_platform_intrinsics
 HOST_CRATES := syntax $(RUSTC_CRATES) rustdoc fmt_macros
 TOOLS := compiletest rustdoc rustc rustbook error-index-generator
 
@@ -74,15 +74,16 @@ DEPS_rustc_driver := arena flate getopts graphviz libc rustc rustc_back rustc_bo
 		     rustc_trans rustc_privacy rustc_lint
 
 DEPS_rustc_trans := arena flate getopts graphviz libc rustc rustc_back \
-	                log syntax serialize rustc_llvm
-DEPS_rustc_typeck := rustc syntax
+	                log syntax serialize rustc_llvm rustc_platform_intrinsics
+DEPS_rustc_typeck := rustc syntax rustc_platform_intrinsics
 DEPS_rustc_borrowck := rustc log graphviz syntax
 DEPS_rustc_resolve := rustc log syntax
 DEPS_rustc_privacy := rustc log syntax
 DEPS_rustc_lint := rustc log syntax
 DEPS_rustc := syntax flate arena serialize getopts rbml \
               log graphviz rustc_llvm rustc_back rustc_data_structures
 DEPS_rustc_llvm := native:rustllvm libc std rustc_bitflags
+DEPS_rustc_platform_intrinsics := rustc rustc_llvm
 DEPS_rustc_back := std syntax rustc_llvm flate log libc
 DEPS_rustc_data_structures := std log serialize
 DEPS_rustdoc := rustc rustc_driver native:hoedown serialize getopts \

branches/try/mk/target.mk

@@ -13,6 +13,10 @@
 # this exists can be found on issue #2400
 export CFG_COMPILER_HOST_TRIPLE
 
+# Used as defaults for the runtime ar and cc tools
+export CFG_DEFAULT_LINKER
+export CFG_DEFAULT_AR
+
 # The standard libraries should be held up to a higher standard than any old
 # code, make sure that these common warnings are denied by default. These can
 # be overridden during development temporarily. For stage0, we allow warnings

branches/try/src/doc/nomicon/coercions.md

@@ -22,7 +22,7 @@ Coercion is allowed between the following types:
 for all pointer types (including smart pointers like Box and Rc). Unsize is
 only implemented automatically, and enables the following transformations:
 
-* `[T, ..n]` => `[T]`
+* `[T; n]` => `[T]`
 * `T` => `Trait` where `T: Trait`
 * `Foo<..., T, ...>` => `Foo<..., U, ...>` where:
     * `T: Unsize<U>`

branches/try/src/doc/nomicon/safe-unsafe-meaning.md

@@ -125,7 +125,7 @@ unsafe impl UnsafeOrd for MyType {
 But it's probably not the implementation you want.
 
 Rust has traditionally avoided making traits unsafe because it makes Unsafe
-pervasive, which is not desirable. Send and Sync are unsafe is because thread
+pervasive, which is not desirable. The reason Send and Sync are unsafe is because thread
 safety is a *fundamental property* that unsafe code cannot possibly hope to defend
 against in the same way it would defend against a bad Ord implementation. The
 only way to possibly defend against thread-unsafety would be to *not use

branches/try/src/doc/reference.md

@@ -2059,6 +2059,11 @@ The following configurations must be defined by the implementation:
   `"mips"`, `"powerpc"`, `"arm"`, or `"aarch64"`.
 * `target_endian = "..."`. Endianness of the target CPU, either `"little"` or
   `"big"`.
+* `target_env = ".."` - an option provided by the compiler by default
+  describing the runtime environment of the target platform. Some examples of
+  this are `musl` for builds targeting the MUSL libc implementation, `msvc` for
+  Windows builds targeting MSVC, and `gnu` frequently the rest of the time. This
+  option may also be blank on some platforms.
 * `target_family = "..."`. Operating system family of the target, e. g.
   `"unix"` or `"windows"`. The value of this configuration option is defined
   as a configuration itself, like `unix` or `windows`.
@@ -2068,6 +2073,7 @@ The following configurations must be defined by the implementation:
 * `target_pointer_width = "..."`. Target pointer width in bits. This is set
   to `"32"` for targets with 32-bit pointers, and likewise set to `"64"` for
   64-bit pointers.
+* `test`. Enabled when compiling the test harness (using the `--test` flag).
 * `unix`. See `target_family`.
 * `windows`. See `target_family`.
 

branches/try/src/doc/trpl/concurrency.md

@@ -343,12 +343,14 @@ threads as a simple isolation mechanism:
 ```rust
 use std::thread;
 
-let result = thread::spawn(move || {
+let handle = thread::spawn(move || {
     panic!("oops!");
-}).join();
+});
+
+let result = handle.join();
 
 assert!(result.is_err());
 ```
 
-Our `Thread` gives us a `Result` back, which allows us to check if the thread
+`Thread.join()` gives us a `Result` back, which allows us to check if the thread
 has panicked or not.

branches/try/src/doc/trpl/documentation.md

@@ -73,8 +73,8 @@ hello.rs:4 }
 ```
 
 This [unfortunate error](https://github.com/rust-lang/rust/issues/22547) is
-correct: documentation comments apply to the thing after them, and there's no
-thing after that last comment.
+correct: documentation comments apply to the thing after them, and there's 
+nothing after that last comment.
 
 [rc-new]: https://doc.rust-lang.org/nightly/std/rc/struct.Rc.html#method.new
 
@@ -196,10 +196,10 @@ This will highlight according to whatever language you're showing off.
 If you're just showing plain text, choose `text`.
 
 It's important to choose the correct annotation here, because `rustdoc` uses it
-in an interesting way: It can be used to actually test your examples, so that
-they don't get out of date. If you have some C code but `rustdoc` thinks it's
-Rust because you left off the annotation, `rustdoc` will complain when trying to
-generate the documentation.
+in an interesting way: It can be used to actually test your examples in a
+library crate, so that they don't get out of date. If you have some C code but
+`rustdoc` thinks it's Rust because you left off the annotation, `rustdoc` will
+complain when trying to generate the documentation.
 
 ## Documentation as tests
 
@@ -377,8 +377,8 @@ $ rustdoc --test path/to/my/crate/root.rs
 $ cargo test
 ```
 
-That's right, `cargo test` tests embedded documentation too. However,
-`cargo test` will not test binary crates, only library ones. This is
+That's right, `cargo test` tests embedded documentation too. **However,
+`cargo test` will not test binary crates, only library ones.** This is
 due to the way `rustdoc` works: it links against the library to be tested,
 but with a binary, there’s nothing to link to.
 

branches/try/src/doc/trpl/functions.md

@@ -214,11 +214,61 @@ fn diverges() -> ! {
 
 `panic!` is a macro, similar to `println!()` that we’ve already seen. Unlike
 `println!()`, `panic!()` causes the current thread of execution to crash with
-the given message.
+the given message. Because this function will cause a crash, it will never
+return, and so it has the type ‘`!`’, which is read ‘diverges’.
 
-Because this function will cause a crash, it will never return, and so it has
-the type ‘`!`’, which is read ‘diverges’. A diverging function can be used
-as any type:
+If you add a main function that calls `diverges()` and run it, you’ll get
+some output that looks like this:
+
+```text
+thread ‘<main>’ panicked at ‘This function never returns!’, hello.rs:2
+```
+
+If you want more information, you can get a backtrace by setting the
+`RUST_BACKTRACE` environment variable:
+
+```text
+$ RUST_BACKTRACE=1 ./diverges
+thread '<main>' panicked at 'This function never returns!', hello.rs:2
+stack backtrace:
+   1:     0x7f402773a829 - sys::backtrace::write::h0942de78b6c02817K8r
+   2:     0x7f402773d7fc - panicking::on_panic::h3f23f9d0b5f4c91bu9w
+   3:     0x7f402773960e - rt::unwind::begin_unwind_inner::h2844b8c5e81e79558Bw
+   4:     0x7f4027738893 - rt::unwind::begin_unwind::h4375279447423903650
+   5:     0x7f4027738809 - diverges::h2266b4c4b850236beaa
+   6:     0x7f40277389e5 - main::h19bb1149c2f00ecfBaa
+   7:     0x7f402773f514 - rt::unwind::try::try_fn::h13186883479104382231
+   8:     0x7f402773d1d8 - __rust_try
+   9:     0x7f402773f201 - rt::lang_start::ha172a3ce74bb453aK5w
+  10:     0x7f4027738a19 - main
+  11:     0x7f402694ab44 - __libc_start_main
+  12:     0x7f40277386c8 - <unknown>
+  13:                0x0 - <unknown>
+```
+
+`RUST_BACKTRACE` also works with Cargo’s `run` command:
+
+```text
+$ RUST_BACKTRACE=1 cargo run
+     Running `target/debug/diverges`
+thread '<main>' panicked at 'This function never returns!', hello.rs:2
+stack backtrace:
+   1:     0x7f402773a829 - sys::backtrace::write::h0942de78b6c02817K8r
+   2:     0x7f402773d7fc - panicking::on_panic::h3f23f9d0b5f4c91bu9w
+   3:     0x7f402773960e - rt::unwind::begin_unwind_inner::h2844b8c5e81e79558Bw
+   4:     0x7f4027738893 - rt::unwind::begin_unwind::h4375279447423903650
+   5:     0x7f4027738809 - diverges::h2266b4c4b850236beaa
+   6:     0x7f40277389e5 - main::h19bb1149c2f00ecfBaa
+   7:     0x7f402773f514 - rt::unwind::try::try_fn::h13186883479104382231
+   8:     0x7f402773d1d8 - __rust_try
+   9:     0x7f402773f201 - rt::lang_start::ha172a3ce74bb453aK5w
+  10:     0x7f4027738a19 - main
+  11:     0x7f402694ab44 - __libc_start_main
+  12:     0x7f40277386c8 - <unknown>
+  13:                0x0 - <unknown>
+```
+
+A diverging function can be used as any type:
 
 ```should_panic
 # fn diverges() -> ! {

branches/try/src/doc/trpl/testing.md

@@ -355,8 +355,8 @@ Let's finally check out that third section: documentation tests.
 Nothing is better than documentation with examples. Nothing is worse than
 examples that don't actually work, because the code has changed since the
 documentation has been written. To this end, Rust supports automatically
-running examples in your documentation. Here's a fleshed-out `src/lib.rs`
-with examples:
+running examples in your documentation (**note:** this only works in library
+crates, not binary crates). Here's a fleshed-out `src/lib.rs` with examples:
 
 ```rust,ignore
 //! The `adder` crate provides functions that add numbers to other numbers.

branches/try/src/doc/trpl/trait-objects.md

@@ -300,3 +300,41 @@ let y = TraitObject {
 // y.method();
 (y.vtable.method)(y.data);
 ```
+
+## Object Safety
+
+Not every trait can be used to make a trait object. For example, vectors implement
+`Clone`, but if we try to make a trait object:
+
+```ignore
+let v = vec![1, 2, 3];
+let o = &v as &Clone;
+```
+
+We get an error:
+
+```text
+error: cannot convert to a trait object because trait `core::clone::Clone` is not object-safe [E0038]
+let o = &v as &Clone;
+        ^~
+note: the trait cannot require that `Self : Sized`
+let o = &v as &Clone;
+        ^~
+```
+
+The error says that `Clone` is not ‘object-safe’. Only traits that are
+object-safe can be made into trait objects. A trait is object-safe if both of
+these are true:
+
+* the trait does not require that `Self: Sized`
+* all of its methods are object-safe
+
+So what makes a method object-safe? Each method must require that `Self: Sized`
+or all of the following:
+
+* must not have any type parameters
+* must not use `Self`
+
+Whew! As we can see, almost all of these rules talk about `Self`. A good intuition
+is “except in special circumstances, if your trait’s method uses `Self`, it is not
+object-safe.”