Auto merge of #33758 - GuillaumeGomez:rollup, r=Manishearth

Rollup of 6 pull requests

- Successful merges: #33668, #33676, #33683, #33734, #33739, #33745
- Failed merges: #33578

Author: bors

src/doc/book/casting-between-types.md

@@ -135,14 +135,14 @@ cast four bytes into a `u32`:
 ```rust,ignore
 let a = [0u8, 0u8, 0u8, 0u8];
 
-let b = a as u32; // four eights makes 32
+let b = a as u32; // four u8s makes a u32
 ```
 
 This errors with:
 
 ```text
 error: non-scalar cast: `[u8; 4]` as `u32`
-let b = a as u32; // four eights makes 32
+let b = a as u32; // four u8s makes a u32
         ^~~~~~~~
 ```
 

src/libcore/macros.rs

@@ -86,7 +86,7 @@ macro_rules! assert {
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! assert_eq {
     ($left:expr , $right:expr) => ({
-        match (&($left), &($right)) {
+        match (&$left, &$right) {
             (left_val, right_val) => {
                 if !(*left_val == *right_val) {
                     panic!("assertion failed: `(left == right)` \

src/libcore/sync/atomic.rs

@@ -26,8 +26,9 @@
 //! [1]: http://llvm.org/docs/LangRef.html#memory-model-for-concurrent-operations
 //!
 //! Atomic variables are safe to share between threads (they implement `Sync`)
-//! but they do not themselves provide the mechanism for sharing. The most
-//! common way to share an atomic variable is to put it into an `Arc` (an
+//! but they do not themselves provide the mechanism for sharing and follow the
+//! [threading model](../../../std/thread/index.html#the-threading-model) of rust.
+//! The most common way to share an atomic variable is to put it into an `Arc` (an
 //! atomically-reference-counted shared pointer).
 //!
 //! Most atomic types may be stored in static variables, initialized using
@@ -48,12 +49,16 @@
 //!     let spinlock = Arc::new(AtomicUsize::new(1));
 //!
 //!     let spinlock_clone = spinlock.clone();
-//!     thread::spawn(move|| {
+//!     let thread = thread::spawn(move|| {
 //!         spinlock_clone.store(0, Ordering::SeqCst);
 //!     });
 //!
 //!     // Wait for the other thread to release the lock
 //!     while spinlock.load(Ordering::SeqCst) != 0 {}
+//!
+//!     if let Err(panic) = thread.join() {
+//!         println!("Thread had an error: {:?}", panic);
+//!     }
 //! }
 //! ```
 //!

src/librustc/hir/lowering.rs

@@ -1286,8 +1286,12 @@ impl<'a> LoweringContext<'a> {
                                     maybe_expr.as_ref().map(|x| self.lower_expr(x)))
                 }
                 ExprKind::Paren(ref ex) => {
-                    // merge attributes into the inner expression.
                     return self.lower_expr(ex).map(|mut ex| {
+                        // include parens in span, but only if it is a super-span.
+                        if e.span.contains(ex.span) {
+                            ex.span = e.span;
+                        }
+                        // merge attributes into the inner expression.
                         ex.attrs.update(|attrs| {
                             attrs.prepend(e.attrs.clone())
                         });

src/librustc_borrowck/borrowck/gather_loans/move_error.rs

@@ -152,7 +152,7 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
                 ty::TyEnum(def, _) if def.has_dtor() => {
                     let mut err = struct_span_err!(bccx, move_from.span, E0509,
                                                    "cannot move out of type `{}`, \
-                                                   which defines the `Drop` trait",
+                                                   which implements the `Drop` trait",
                                                    b.ty);
                     err.span_label(move_from.span, &format!("cannot move out of here"));
                     err

src/librustc_trans/base.rs

@@ -617,7 +617,13 @@ pub fn coerce_unsized_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
         (&ty::TyRawPtr(..), &ty::TyRawPtr(..)) => {
             let (base, info) = if common::type_is_fat_ptr(bcx.tcx(), src_ty) {
                 // fat-ptr to fat-ptr unsize preserves the vtable
-                load_fat_ptr(bcx, src, src_ty)
+                // i.e. &'a fmt::Debug+Send => &'a fmt::Debug
+                // So we need to pointercast the base to ensure
+                // the types match up.
+                let (base, info) = load_fat_ptr(bcx, src, src_ty);
+                let llcast_ty = type_of::fat_ptr_base_ty(bcx.ccx(), dst_ty);
+                let base = PointerCast(bcx, base, llcast_ty);
+                (base, info)
             } else {
                 let base = load_ty(bcx, src, src_ty);
                 unsize_thin_ptr(bcx, base, src_ty, dst_ty)

src/librustc_trans/mir/rvalue.rs

@@ -262,14 +262,17 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
                         assert!(common::type_is_fat_ptr(bcx.tcx(), cast_ty));
 
                         match operand.val {
-                            OperandValue::FatPtr(..) => {
+                            OperandValue::FatPtr(lldata, llextra) => {
                                 // unsize from a fat pointer - this is a
                                 // "trait-object-to-supertrait" coercion, for
                                 // example,
                                 //   &'a fmt::Debug+Send => &'a fmt::Debug,
-                                // and is a no-op at the LLVM level
+                                // So we need to pointercast the base to ensure
+                                // the types match up.
                                 self.set_operand_dropped(&bcx, source);
-                                operand.val
+                                let llcast_ty = type_of::fat_ptr_base_ty(bcx.ccx(), cast_ty);
+                                let lldata = bcx.pointercast(lldata, llcast_ty);
+                                OperandValue::FatPtr(lldata, llextra)
                             }
                             OperandValue::Immediate(lldata) => {
                                 // "standard" unsize

src/librustc_trans/type_of.rs

@@ -157,6 +157,17 @@ pub fn sizing_type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>) -> Typ
     llsizingty
 }
 
+pub fn fat_ptr_base_ty<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> Type {
+    match ty.sty {
+        ty::TyBox(t) |
+        ty::TyRef(_, ty::TypeAndMut { ty: t, .. }) |
+        ty::TyRawPtr(ty::TypeAndMut { ty: t, .. }) if !type_is_sized(ccx.tcx(), t) => {
+            in_memory_type_of(ccx, t).ptr_to()
+        }
+        _ => bug!("expected fat ptr ty but got {:?}", ty)
+    }
+}
+
 fn unsized_info_ty<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -> Type {
     let unsized_part = ccx.tcx().struct_tail(ty);
     match unsized_part.sty {

src/test/compile-fail/E0036.rs

@@ -0,0 +1,23 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct Test;
+
+impl Test {
+    fn method<T>(&self, v: &[T]) -> usize {
+        v.len()
+    }
+}
+
+fn main() {
+    let x = Test;
+    let v = &[0];
+    x.method::<i32, i32>(v); //~ ERROR E0036
+}

src/test/compile-fail/E0038.rs

@@ -0,0 +1,20 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+trait Trait {
+    fn foo(&self) -> Self;
+}
+
+fn call_foo(x: Box<Trait>) { //~ ERROR E0038
+    let y = x.foo();
+}
+
+fn main() {
+}