---

yaml
---
r: 218959
b: refs/heads/snap-stage3
c: ef72938
h: refs/heads/master
i:
  218957: 124ad22
  218955: 53ffbf8
  218951: bafa40f
  218943: 5255f33
v: v3

Author: bors

[refs]

@@ -1,6 +1,6 @@
 ---
 refs/heads/master: c044791d80ea0dc5c4b57b6030a67b69f8510239
-refs/heads/snap-stage3: 7f3ae0aa26d24100379ae0f3eef29916a32f4e79
+refs/heads/snap-stage3: ef72938a8b9171abc5c4b463d3e8345dc0e603a6
 refs/heads/try: b53c0f93eedcdedd4fd89bccc5a3a09d1c5cd23e
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596

branches/snap-stage3/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]>

branches/snap-stage3/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)

branches/snap-stage3/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.

branches/snap-stage3/src/libcollections/linked_list.rs

@@ -609,7 +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;
 
@@ -1075,6 +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();

branches/snap-stage3/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")]
 

branches/snap-stage3/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,

branches/snap-stage3/src/librustc/metadata/csearch.rs

@@ -13,7 +13,6 @@
 use metadata::common::*;
 use metadata::cstore;
 use metadata::decoder;
-use middle::def;
 use middle::lang_items;
 use middle::ty;
 
@@ -114,12 +113,6 @@ pub fn maybe_get_item_ast<'tcx>(tcx: &ty::ctxt<'tcx>, def: ast::DefId,
     decoder::maybe_get_item_ast(&*cdata, tcx, def.node, decode_inlined_item)
 }
 
-pub fn get_enum_variant_defs(cstore: &cstore::CStore, enum_id: ast::DefId)
-                             -> Vec<(def::Def, ast::Name, ast::Visibility)> {
-    let cdata = cstore.get_crate_data(enum_id.krate);
-    decoder::get_enum_variant_defs(&*cstore.intr, &*cdata, enum_id.node)
-}
-
 pub fn get_enum_variants<'tcx>(tcx: &ty::ctxt<'tcx>, def: ast::DefId)
                                -> Vec<Rc<ty::VariantInfo<'tcx>>> {
     let cstore = &tcx.sess.cstore;

branches/snap-stage3/src/librustc/metadata/decoder.rs

@@ -268,30 +268,6 @@ fn item_trait_ref<'tcx>(doc: rbml::Doc, tcx: &ty::ctxt<'tcx>, cdata: Cmd)
     doc_trait_ref(tp, tcx, cdata)
 }
 
-struct EnumVariantIds<'a> {
-    iter: reader::TaggedDocsIterator<'a>,
-    cdata: Cmd<'a>,
-}
-
-impl<'a> Iterator for EnumVariantIds<'a> {
-    type Item = ast::DefId;
-
-    fn next(&mut self) -> Option<ast::DefId> {
-        self.iter.next().map(|p| translated_def_id(self.cdata, p))
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
-    }
-}
-
-fn enum_variant_ids<'a>(item: rbml::Doc<'a>, cdata: Cmd<'a>) -> EnumVariantIds<'a> {
-    EnumVariantIds {
-        iter: reader::tagged_docs(item, tag_items_data_item_variant),
-        cdata: cdata,
-    }
-}
-
 fn item_path(item_doc: rbml::Doc) -> Vec<ast_map::PathElem> {
     let path_doc = reader::get_doc(item_doc, tag_path);
     reader::docs(path_doc).filter_map(|(tag, elt_doc)| {
@@ -730,31 +706,14 @@ pub fn maybe_get_item_ast<'tcx>(cdata: Cmd, tcx: &ty::ctxt<'tcx>, id: ast::NodeI
     }
 }
 
-pub fn get_enum_variant_defs(intr: &IdentInterner,
-                             cdata: Cmd,
-                             id: ast::NodeId)
-                             -> Vec<(def::Def, ast::Name, ast::Visibility)> {
-    let data = cdata.data();
-    let items = reader::get_doc(rbml::Doc::new(data), tag_items);
-    let item = find_item(id, items);
-    enum_variant_ids(item, cdata).map(|did| {
-        let item = find_item(did.node, items);
-        let name = item_name(intr, item);
-        let visibility = item_visibility(item);
-        match item_to_def_like(cdata, item, did) {
-            DlDef(def @ def::DefVariant(..)) => (def, name, visibility),
-            _ => unreachable!()
-        }
-    }).collect()
-}
-
 pub fn get_enum_variants<'tcx>(intr: Rc<IdentInterner>, cdata: Cmd, id: ast::NodeId,
                                tcx: &ty::ctxt<'tcx>) -> Vec<Rc<ty::VariantInfo<'tcx>>> {
     let data = cdata.data();
     let items = reader::get_doc(rbml::Doc::new(data), tag_items);
     let item = find_item(id, items);
     let mut disr_val = 0;
-    enum_variant_ids(item, cdata).map(|did| {
+    reader::tagged_docs(item, tag_items_data_item_variant).map(|p| {
+        let did = translated_def_id(cdata, p);
         let item = find_item(did.node, items);
         let ctor_ty = item_type(ast::DefId { krate: cdata.cnum, node: id},
                                 item, tcx, cdata);

branches/snap-stage3/src/librustc/middle/subst.rs

@@ -448,20 +448,6 @@ impl<T> VecPerParamSpace<T> {
                                        self.self_limit)
     }
 
-    pub fn map_move<U, F>(self, mut pred: F) -> VecPerParamSpace<U> where
-        F: FnMut(T) -> U,
-    {
-        let SeparateVecsPerParamSpace {
-            types: t,
-            selfs: s,
-            fns: f
-        } = self.split();
-
-        VecPerParamSpace::new(t.into_iter().map(|p| pred(p)).collect(),
-                              s.into_iter().map(|p| pred(p)).collect(),
-                              f.into_iter().map(|p| pred(p)).collect())
-    }
-
     pub fn split(self) -> SeparateVecsPerParamSpace<T> {
         let VecPerParamSpace { type_limit, self_limit, content } = self;
 

branches/snap-stage3/src/librustc/middle/traits/fulfill.rs

@@ -329,7 +329,7 @@ fn process_predicate<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
                     false
                 }
                 Ok(Some(s)) => {
-                    s.map_move_nested(|p| new_obligations.push(p));
+                    new_obligations.append(&mut s.nested_obligations());
                     true
                 }
                 Err(selection_err) => {