---

yaml
---
r: 212333
b: refs/heads/master
c: 61c43b4
h: refs/heads/master
i:
  212331: 4f93159
v: v3

Author: bors

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: 905727246a38d72d6df7608ca976e1880ddc6a85
+refs/heads/master: 61c43b47338b92c447c1f6af5cffec46718e750b
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: ba0e1cd8147d452c356aacb29fb87568ca26f111
 refs/heads/try: 1864973ae17213c5a58c4dd3f9af6d1b6c7d2e05

trunk/AUTHORS.txt

@@ -338,7 +338,7 @@ Hajime Morrita <[email protected]>
 Hanno Braun <[email protected]>
 Harry Marr <[email protected]>
 Heather <[email protected]>
-Heejong Ahn <[email protected]
+Heejong Ahn <[email protected]>
 Henrik Schopmans <[email protected]>
 Herman J. Radtke III <[email protected]>
 HeroesGrave <[email protected]>

trunk/configure

@@ -582,6 +582,7 @@ valopt sysconfdir "/etc" "install system configuration files"
 valopt datadir "${CFG_PREFIX}/share" "install data"
 valopt infodir "${CFG_PREFIX}/share/info" "install additional info"
 valopt llvm-root "" "set LLVM root"
+valopt python "" "set path to python"
 valopt jemalloc-root "" "set directory where libjemalloc_pic.a is located"
 valopt build "${DEFAULT_BUILD}" "GNUs ./configure syntax LLVM build triple"
 valopt android-cross-path "/opt/ndk_standalone" "Android NDK standalone path"
@@ -695,7 +696,9 @@ putvar CFG_BOOTSTRAP_KEY
 step_msg "looking for build programs"
 
 probe_need CFG_CURLORWGET  curl wget
-probe_need CFG_PYTHON      python2.7 python2.6 python2 python
+if [ -z "$CFG_PYTHON_PROVIDED" ]; then
+    probe_need CFG_PYTHON      python2.7 python2.6 python2 python
+fi
 
 python_version=$($CFG_PYTHON -V 2>&1)
 if [ $(echo $python_version | grep -c '^Python 2\.[4567]') -ne 1 ]; then
@@ -849,13 +852,6 @@ then
     putvar CFG_LOCAL_RUST_ROOT
 fi
 
-# Force freebsd to build with clang; gcc doesn't like us there
-if [ $CFG_OSTYPE = unknown-freebsd ]
-then
-    step_msg "on FreeBSD, forcing use of clang"
-    CFG_ENABLE_CLANG=1
-fi
-
 # Force bitrig to build with clang; gcc doesn't like us there
 if [ $CFG_OSTYPE = unknown-bitrig ]
 then
@@ -973,8 +969,8 @@ fi
 
 if [ ! -z "$CFG_ENABLE_CLANG" ]
 then
-    if [ -z "$CC" ] || [[ $CC == *clang ]]
-    then
+    case "$CC" in
+        (''|*clang)
         CFG_CLANG_VERSION=$($CFG_CC \
             --version \
             | grep version \
@@ -994,9 +990,11 @@ then
             err "bad CLANG version: $CFG_CLANG_VERSION, need >=3.0svn"
             ;;
         esac
-    else
+        ;;
+        (*)
         msg "skipping CFG_ENABLE_CLANG version check; provided CC=$CC"
-    fi
+        ;;
+    esac
 fi
 
 if [ ! -z "$CFG_ENABLE_CCACHE" ]
@@ -1309,6 +1307,12 @@ CFG_LLVM_SRC_DIR=${CFG_SRC_DIR}src/llvm/
 for t in $CFG_HOST
 do
     do_reconfigure=1
+    is_msvc=0
+    case "$t" in
+        (*-msvc)
+        is_msvc=1
+        ;;
+    esac
 
     if [ -z $CFG_LLVM_ROOT ]
     then
@@ -1328,7 +1332,13 @@ do
             LLVM_ASSERTION_OPTS="--disable-assertions"
         else
             LLVM_ASSERTION_OPTS="--enable-assertions"
-            LLVM_INST_DIR=${LLVM_INST_DIR}+Asserts
+
+            # Apparently even if we request assertions be enabled for MSVC,
+            # LLVM's CMake build system ignore this and outputs in `Release`
+            # anyway.
+            if [ ${is_msvc} -eq 0 ]; then
+                LLVM_INST_DIR=${LLVM_INST_DIR}+Asserts
+            fi
         fi
     else
         msg "not reconfiguring LLVM, external LLVM root"
@@ -1358,14 +1368,7 @@ do
         done
     fi
 
-    use_cmake=0
-    case "$t" in
-        (*-msvc)
-        use_cmake=1
-        ;;
-    esac
-
-    if [ ${do_reconfigure} -ne 0 ] && [ ${use_cmake} -ne 0 ]
+    if [ ${do_reconfigure} -ne 0 ] && [ ${is_msvc} -ne 0 ]
     then
         msg "configuring LLVM for $t with cmake"
 
@@ -1390,7 +1393,7 @@ do
         need_ok "LLVM cmake configure failed"
     fi
 
-    if [ ${do_reconfigure} -ne 0 ] && [ ${use_cmake} -eq 0 ]
+    if [ ${do_reconfigure} -ne 0 ] && [ ${is_msvc} -eq 0 ]
     then
         # LLVM's configure doesn't recognize the new Windows triples yet
         gnu_t=$(to_gnu_triple $t)

trunk/mk/docs.mk

@@ -265,7 +265,7 @@ endef
 $(foreach crate,$(CRATES),$(eval $(call DEF_LIB_DOC,$(crate))))
 
 COMPILER_DOC_TARGETS := $(CRATES:%=doc/%/index.html)
-ifdef CFG_COMPILER_DOCS
+ifdef CFG_ENABLE_COMPILER_DOCS
   DOC_TARGETS += $(COMPILER_DOC_TARGETS)
 else
   DOC_TARGETS += $(DOC_CRATES:%=doc/%/index.html)

trunk/src/compiletest/runtest.rs

@@ -24,7 +24,6 @@ use std::fmt;
 use std::fs::{self, File};
 use std::io::BufReader;
 use std::io::prelude::*;
-use std::iter::repeat;
 use std::net::TcpStream;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Output, ExitStatus};
@@ -928,12 +927,12 @@ fn check_forbid_output(props: &TestProps,
     }
 }
 
-fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
+fn check_expected_errors(expected_errors: Vec<errors::ExpectedError>,
                          testfile: &Path,
                          proc_res: &ProcRes) {
 
     // true if we found the error in question
-    let mut found_flags: Vec<_> = repeat(false).take(expected_errors.len()).collect();
+    let mut found_flags = vec![false; expected_errors.len()];
 
     if proc_res.status.success() {
         fatal("process did not return an error status");
@@ -954,14 +953,10 @@ fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
         }
     }
 
-    // A multi-line error will have followup lines which will always
-    // start with one of these strings.
+    // A multi-line error will have followup lines which start with a space
+    // or open paren.
     fn continuation( line: &str) -> bool {
-        line.starts_with(" expected") ||
-        line.starts_with("    found") ||
-        //                1234
-        // Should have 4 spaces: see issue 18946
-        line.starts_with("(")
+        line.starts_with(" ") || line.starts_with("(")
     }
 
     // Scan and extract our error/warning messages,

trunk/src/doc/index.md

@@ -25,7 +25,7 @@ series of small examples.
 If you need help with something, or just want to talk about Rust with others,
 there are a few places you can do that:
 
-The Rust IRC channels on [irc.mozilla.org](http://irc.mozilla.org/) are the
+The Rust IRC channels on [irc.mozilla.org](irc://irc.mozilla.org/) are the
 fastest way to get help.
 [`#rust`](http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust) is
 the general discussion channel, and you'll find people willing to help you with
@@ -40,15 +40,15 @@ There's also
 [`#rust-internals`](http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-internals), which is for discussion of the development of Rust itself.
 
 You can also get help on [Stack
-Overflow](http://stackoverflow.com/questions/tagged/rust). Searching for your
+Overflow](https://stackoverflow.com/questions/tagged/rust). Searching for your
 problem might reveal someone who has asked it before!
 
-There is an active [subreddit](http://reddit.com/r/rust) with lots of
+There is an active [subreddit](https://reddit.com/r/rust) with lots of
 discussion and news about Rust.
 
-There is also a [user forum](http://users.rust-lang.org), for all
-user-oriented discussion, and a [developer
-forum](http://internals.rust-lang.org/), where the development of Rust
+There is also a [user forum](https://users.rust-lang.org), for all
+user-oriented discussion, and a [developer 
+forum](https://internals.rust-lang.org/), where the development of Rust
 itself is discussed.
 
 # Specification
@@ -61,7 +61,7 @@ the language in as much detail as possible is in [the reference](reference.html)
 Rust is still a young language, so there isn't a ton of tooling yet, but the
 tools we have are really nice.
 
-[Cargo](http://crates.io) is Rust's package manager, and its website contains
+[Cargo](https://crates.io) is Rust's package manager, and its website contains
 lots of good documentation.
 
 [`rustdoc`](book/documentation.html) is used to generate documentation for Rust code.

trunk/src/doc/reference.md

@@ -1943,9 +1943,6 @@ macro scope.
 - `simd` - on certain tuple structs, derive the arithmetic operators, which
   lower to the target's SIMD instructions, if any; the `simd` feature gate
   is necessary to use this attribute.
-- `static_assert` - on statics whose type is `bool`, terminates compilation
-  with an error if it is not initialized to `true`. To use this, the `static_assert`
-  feature gate must be enabled.
 - `unsafe_no_drop_flag` - on structs, remove the flag that prevents
   destructors from being run twice. Destructors might be run multiple times on
   the same object with this attribute. To use this, the `unsafe_no_drop_flag` feature
@@ -2301,12 +2298,6 @@ The currently implemented features of the reference compiler are:
                  crate. Stability markers are also attributes: `#[stable]`,
                  `#[unstable]`, and `#[deprecated]` are the three levels.
 
-* `static_assert` - The `#[static_assert]` functionality is experimental and
-                    unstable. The attribute can be attached to a `static` of
-                    type `bool` and the compiler will error if the `bool` is
-                    `false` at compile time. This version of this functionality
-                    is unintuitive and suboptimal.
-
 * `start` - Allows use of the `#[start]` attribute, which changes the entry point
             into a Rust program. This capability, especially the signature for the
             annotated function, is subject to change.
@@ -3608,6 +3599,147 @@ The notation `&self` is a shorthand for `self: &Self`. In this case,
 in the impl, `Self` refers to the value of type `String` that is the
 receiver for a call to the method `make_string`.
 
+## Subtyping
+
+Subtyping is implicit and can occur at any stage in type checking or
+inference. Subtyping in Rust is very restricted and occurs only due to
+variance with respect to lifetimes and between types with higher ranked
+lifetimes. If we were to erase lifetimes from types, then the only subtyping
+would be due to type equality.
+
+Consider the following example: string literals always have `'static`
+lifetime. Nevertheless, we can assign `s` to `t`:
+
+```
+fn bar<'a>() {
+    let s: &'static str = "hi";
+    let t: &'a str = s;
+}
+```
+Since `'static` "lives longer" than `'a`, `&'static str` is a subtype of
+`&'a str`.
+
+## Type coercions
+
+Coercions are defined in [RFC401]. A coercion is implicit and has no syntax.
+
+[RFC401]: https://github.com/rust-lang/rfcs/blob/master/text/0401-coercions.md
+
+### Coercion sites
+
+A coercion can only occur at certain coercion sites in a program; these are
+typically places where the desired type is explicit or can be dervied by
+propagation from explicit types (without type inference). Possible coercion
+sites are:
+
+* `let` statements where an explicit type is given.
+
+    In `let _: U = e;`, `e` is coerced to have type `U`.
+
+* `static` and `const` statements (similar to `let` statements).
+
+* arguments for function calls.
+
+    The value being coerced is the
+    actual parameter and it is coerced to the type of the formal parameter. For
+    example, let `foo` be defined as `fn foo(x: U) { ... }` and call it as
+    `foo(e);`. Then `e` is coerced to have type `U`;
+
+* instantiations of struct or variant fields.
+
+    Assume we have a `struct
+    Foo { x: U }` and instantiate it as `Foo { x: e }`. Then `e` is coerced to
+    have type `U`.
+
+* function results (either the final line of a block if it is not semicolon
+terminated or any expression in a `return` statement).
+
+    In `fn foo() -> U { e }`, `e` is coerced to to have type `U`.
+
+If the expression in one of these coercion sites is a coercion-propagating
+expression, then the relevant sub-expressions in that expression are also
+coercion sites. Propagation recurses from these new coercion sites.
+Propagating expressions and their relevant sub-expressions are:
+
+* array literals, where the array has type `[U; n]`. Each sub-expression in
+the array literal is a coercion site for coercion to type `U`.
+
+* array literals with repeating syntax, where the array has type `[U; n]`. The
+repeated sub-expression is a coercion site for coercion to type `U`.
+
+* tuples, where a tuple is a coercion site to type `(U_0, U_1, ..., U_n)`.
+Each sub-expression is a coercion site to the respective type, e.g. the
+zeroth sub-expression is a coercion site to type `U_0`.
+
+* parenthesised sub-expressions (`(e)`). If the expression has type `U`, then
+the sub-expression is a coercion site to `U`.
+
+* blocks. If a block has type `U`, then the last expression in the block (if
+it is not semicolon-terminated) is a coercion site to `U`. This includes
+blocks which are part of control flow statements, such as `if`/`else`, if
+the block has a known type.
+
+### Coercion types
+
+Coercion is allowed between the following types:
+
+* `T` to `U` if `T` is a subtype of `U` (*reflexive case*).
+
+* `T_1` to `T_3` where `T_1` coerces to `T_2` and `T_2` coerces to `T_3`
+(*transitive case*).
+
+    Note that this is not fully supported yet
+
+* `&mut T` to `&T`.
+
+* `*mut T` to `*const T`.
+
+* `&T` to `*const T`.
+
+* `&mut T` to `*mut T`.
+
+* `&T` to `&U` if `T` implements `Deref<Target = U>`. For example:
+
+```rust
+use std::ops::Deref;
+
+struct CharContainer {
+    value: char
+}
+
+impl Deref for CharContainer {
+    type Target = char;
+
+    fn deref<'a>(&'a self) -> &'a char {
+        &self.value
+    }
+}
+
+fn foo(arg: &char) {}
+
+fn main() {
+    let x = &mut CharContainer { value: 'y' };
+    foo(x); //&mut CharContainer is coerced to &char.
+}
+```
+* `&mut T` to `&mut U` if `T` implements `DerefMut<Target = U>`.
+
+* TyCtor(`T`) to TyCtor(coerce_inner(`T`)), where TyCtor(`T`) is one of
+    - `&T`
+    - `&mut T`
+    - `*const T`
+    - `*mut T`
+    - `Box<T>`
+
+    and where
+    - coerce_inner(`[T, ..n]`) = `[T]`
+    - coerce_inner(`T`) = `U` where `T` is a concrete type which implements the
+    trait `U`.
+
+    In the future, coerce_inner will be recursively extended to tuples and
+    structs. In addition, coercions from sub-traits to super-traits will be
+    added. See [RFC401] for more details.
+
 # Special traits
 
 Several traits define special evaluation behavior.