---

yaml
---
r: 211625
b: refs/heads/master
c: 0571726
h: refs/heads/master
i:
  211623: 7c673cf
v: v3

Author: steveklabnik

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: 62f66a68da668e2e11758168036f22e6538a5831
+refs/heads/master: 0571726d90bf5e91050bb0de13dc50d49bcb13bd
 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

@@ -1307,6 +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 $CFG_LLVM_ROOT ]
     then
@@ -1326,7 +1332,13 @@ do
             LLVM_ASSERTION_OPTS="--disable-assertions"
         else
             LLVM_ASSERTION_OPTS="--enable-assertions"
-            LLVM_INST_DIR=${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"
@@ -1356,14 +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"
 
@@ -1388,7 +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/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/reference.md

@@ -3599,6 +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.

trunk/src/doc/trpl/for-loops.md

@@ -41,3 +41,45 @@ so our loop will print `0` through `9`, not `10`.
 Rust does not have the “C-style” `for` loop on purpose. Manually controlling
 each element of the loop is complicated and error prone, even for experienced C
 developers.
+
+# Enumerate
+
+When you need to keep track of how many times you already looped, you can use the `.enumerate()` function.
+
+## On ranges:
+
+```rust
+for (i,j) in (5..10).enumerate() {
+    println!("i = {} and j = {}", i, j);
+}
+```
+
+Outputs:
+
+```text
+i = 0 and j = 5
+i = 1 and j = 6
+i = 2 and j = 7
+i = 3 and j = 8
+i = 4 and j = 9
+```
+
+Don't forget to add the parentheses around the range.
+
+## On iterators:
+
+```rust
+# let lines = "hello\nworld".lines();
+for (linenumber, line) in lines.enumerate() {
+    println!("{}: {}", linenumber, line);
+}
+```
+
+Outputs:
+
+```text
+0: Content of line one
+1: Content of line two
+2: Content of line tree
+3: Content of line four
+```

trunk/src/libcollections/linked_list.rs

@@ -106,16 +106,14 @@ impl<T> Rawlink<T> {
     /// Convert the `Rawlink` into an Option value
     fn resolve_immut<'a>(&self) -> Option<&'a T> {
         unsafe {
-            mem::transmute(self.p.as_ref())
+            self.p.as_ref()
         }
     }
 
     /// Convert the `Rawlink` into an Option value
     fn resolve<'a>(&mut self) -> Option<&'a mut T> {
-        if self.p.is_null() {
-            None
-        } else {
-            Some(unsafe { mem::transmute(self.p) })
+        unsafe {
+            self.p.as_mut()
         }
     }
 
@@ -611,7 +609,13 @@ impl<T> LinkedList<T> {
             length: len - at
         };
 
+        // Swap split_node.next with list_head (which is None), nulling out split_node.next,
+        // as it is the new tail.
         mem::swap(&mut split_node.resolve().unwrap().next, &mut splitted_list.list_head);
+        // Null out list_head.prev. Note this `unwrap` won't fail because if at == len
+        // we already branched out at the top of the fn to return the empty list.
+        splitted_list.list_head.as_mut().unwrap().prev = Rawlink::none();
+        // Fix the tail ptr
         self.list_tail = split_node;
         self.length = at;
 
@@ -1077,6 +1081,26 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_26021() {
+        use std::iter::ExactSizeIterator;
+        // There was a bug in split_off that failed to null out the RHS's head's prev ptr.
+        // This caused the RHS's dtor to walk up into the LHS at drop and delete all of
+        // its nodes.
+        //
+        // https://github.com/rust-lang/rust/issues/26021
+        let mut v1 = LinkedList::new();
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        let _ = v1.split_off(3); // Dropping this now should not cause laundry consumption
+        assert_eq!(v1.len(), 3);
+
+        assert_eq!(v1.iter().len(), 3);
+        assert_eq!(v1.iter().collect::<Vec<_>>().len(), 3);
+    }
+
     #[cfg(test)]
     fn fuzz_test(sz: i32) {
         let mut m: LinkedList<_> = LinkedList::new();

trunk/src/libcore/result.rs

@@ -223,7 +223,9 @@
 //! }
 //! ```
 //!
-//! `try!` is imported by the prelude, and is available everywhere.
+//! `try!` is imported by the prelude and is available everywhere, but it can only
+//! be used in functions that return `Result` because of the early return of
+//! `Err` that it provides.
 
 #![stable(feature = "rust1", since = "1.0.0")]
 

trunk/src/liblibc/lib.rs

@@ -6308,8 +6308,8 @@ pub mod funcs {
                                 lpOverlapped: LPOVERLAPPED) -> BOOL;
                 pub fn WriteFile(hFile: HANDLE,
                                  lpBuffer: LPVOID,
-                                 nNumberOfBytesToRead: DWORD,
-                                 lpNumberOfBytesRead: LPDWORD,
+                                 nNumberOfBytesToWrite: DWORD,
+                                 lpNumberOfBytesWritten: LPDWORD,
                                  lpOverlapped: LPOVERLAPPED) -> BOOL;
                 pub fn SetFilePointerEx(hFile: HANDLE,
                                         liDistanceToMove: LARGE_INTEGER,