rollup merge of rust-lang#20341: nikomatsakis/impl-trait-for-trait-2

Conflicts:
	src/librustc/middle/traits/mod.rs
	src/libstd/io/mod.rs
	src/test/run-pass/builtin-superkinds-self-type.rs

Author: alexcrichton

src/libcore/clone.rs

@@ -25,7 +25,7 @@ use kinds::Sized;
 
 /// A common trait for cloning an object.
 #[stable]
-pub trait Clone {
+pub trait Clone : Sized {
     /// Returns a copy of the value.
     #[stable]
     fn clone(&self) -> Self;

src/libcore/fmt/mod.rs

@@ -74,7 +74,26 @@ pub trait Writer {
     ///
     /// This method should generally not be invoked manually, but rather through
     /// the `write!` macro itself.
-    fn write_fmt(&mut self, args: Arguments) -> Result { write(self, args) }
+    fn write_fmt(&mut self, args: Arguments) -> Result {
+        // This Adapter is needed to allow `self` (of type `&mut
+        // Self`) to be cast to a FormatWriter (below) without
+        // requiring a `Sized` bound.
+        struct Adapter<'a,Sized? T:'a>(&'a mut T);
+
+        impl<'a, Sized? T> Writer for Adapter<'a, T>
+            where T: Writer
+        {
+            fn write_str(&mut self, s: &str) -> Result {
+                self.0.write_str(s)
+            }
+
+            fn write_fmt(&mut self, args: Arguments) -> Result {
+                self.0.write_fmt(args)
+            }
+        }
+
+        write(&mut Adapter(self), args)
+    }
 }
 
 /// A struct to represent both where to emit formatting strings to and how they
@@ -579,9 +598,6 @@ impl<'a, Sized? T: Show> Show for &'a T {
 impl<'a, Sized? T: Show> Show for &'a mut T {
     fn fmt(&self, f: &mut Formatter) -> Result { (**self).fmt(f) }
 }
-impl<'a> Show for &'a (Show+'a) {
-    fn fmt(&self, f: &mut Formatter) -> Result { (*self).fmt(f) }
-}
 
 impl Show for bool {
     fn fmt(&self, f: &mut Formatter) -> Result {

src/libcore/iter.rs

@@ -65,6 +65,7 @@ use num::{ToPrimitive, Int};
 use ops::{Add, Deref, FnMut};
 use option::Option;
 use option::Option::{Some, None};
+use std::kinds::Sized;
 use uint;
 
 #[deprecated = "renamed to Extend"] pub use self::Extend as Extendable;
@@ -109,7 +110,7 @@ pub trait Extend<A> {
 
 #[unstable = "new convention for extension traits"]
 /// An extension trait providing numerous methods applicable to all iterators.
-pub trait IteratorExt<A>: Iterator<A> {
+pub trait IteratorExt<A>: Iterator<A> + Sized {
     /// Chain this iterator with another, returning a new iterator that will
     /// finish iterating over the current iterator, and then iterate
     /// over the other specified iterator.
@@ -692,7 +693,7 @@ impl<A, I> IteratorExt<A> for I where I: Iterator<A> {}
 
 /// Extention trait for iterators of pairs.
 #[unstable = "newly added trait, likely to be merged with IteratorExt"]
-pub trait IteratorPairExt<A, B>: Iterator<(A, B)> {
+pub trait IteratorPairExt<A, B>: Iterator<(A, B)> + Sized {
     /// Converts an iterator of pairs into a pair of containers.
     ///
     /// Loops through the entire iterator, collecting the first component of
@@ -738,7 +739,7 @@ pub trait DoubleEndedIterator<A>: Iterator<A> {
 
 /// Extension methods for double-ended iterators.
 #[unstable = "new extension trait convention"]
-pub trait DoubleEndedIteratorExt<A>: DoubleEndedIterator<A> {
+pub trait DoubleEndedIteratorExt<A>: DoubleEndedIterator<A> + Sized {
     /// Change the direction of the iterator
     ///
     /// The flipped iterator swaps the ends on an iterator that can already

src/libcore/num/mod.rs

@@ -980,7 +980,7 @@ impl_to_primitive_float! { f64 }
 
 /// A generic trait for converting a number to a value.
 #[experimental = "trait is likely to be removed"]
-pub trait FromPrimitive {
+pub trait FromPrimitive : ::kinds::Sized {
     /// Convert an `int` to return an optional value of this type. If the
     /// value cannot be represented by this value, the `None` is returned.
     #[inline]

src/libcore/ptr.rs

@@ -92,7 +92,7 @@ use mem;
 use clone::Clone;
 use intrinsics;
 use option::Option::{mod, Some, None};
-use kinds::{Send, Sync};
+use kinds::{Send, Sized, Sync};
 
 use cmp::{PartialEq, Eq, Ord, PartialOrd, Equiv};
 use cmp::Ordering::{mod, Less, Equal, Greater};
@@ -243,7 +243,7 @@ pub unsafe fn write<T>(dst: *mut T, src: T) {
 
 /// Methods on raw pointers
 #[stable]
-pub trait PtrExt<T> {
+pub trait PtrExt<T> : Sized {
     /// Returns the null pointer.
     #[deprecated = "call ptr::null instead"]
     fn null() -> Self;

src/librand/lib.rs

@@ -52,14 +52,14 @@ pub mod reseeding;
 mod rand_impls;
 
 /// A type that can be randomly generated using an `Rng`.
-pub trait Rand {
+pub trait Rand : Sized {
     /// Generates a random instance of this type using the specified source of
     /// randomness.
     fn rand<R: Rng>(rng: &mut R) -> Self;
 }
 
 /// A random number generator.
-pub trait Rng {
+pub trait Rng : Sized {
     /// Return the next random u32.
     ///
     /// This rarely needs to be called directly, prefer `r.gen()` to

src/librustc/middle/infer/combine.rs

@@ -57,7 +57,7 @@ use syntax::ast;
 use syntax::abi;
 use syntax::codemap::Span;
 
-pub trait Combine<'tcx> {
+pub trait Combine<'tcx> : Sized {
     fn infcx<'a>(&'a self) -> &'a InferCtxt<'a, 'tcx>;
     fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx> { self.infcx().tcx }
     fn tag(&self) -> String;

src/librustc/middle/subst.rs

@@ -519,7 +519,7 @@ impl<'a,T> Iterator<(ParamSpace, uint, &'a T)> for EnumeratedItems<'a,T> {
 // `foo`. Or use `foo.subst_spanned(tcx, substs, Some(span))` when
 // there is more information available (for better errors).
 
-pub trait Subst<'tcx> {
+pub trait Subst<'tcx> : Sized {
     fn subst(&self, tcx: &ty::ctxt<'tcx>, substs: &Substs<'tcx>) -> Self {
         self.subst_spanned(tcx, substs, None)
     }

src/librustc/middle/traits/mod.rs

@@ -31,20 +31,27 @@ pub use self::fulfill::{FulfillmentContext, RegionObligation};
 pub use self::project::MismatchedProjectionTypes;
 pub use self::project::normalize;
 pub use self::project::Normalized;
+pub use self::object_safety::is_object_safe;
+pub use self::object_safety::object_safety_violations;
+pub use self::object_safety::ObjectSafetyViolation;
+pub use self::object_safety::MethodViolationCode;
 pub use self::select::SelectionContext;
 pub use self::select::SelectionCache;
 pub use self::select::{MethodMatchResult, MethodMatched, MethodAmbiguous, MethodDidNotMatch};
 pub use self::select::{MethodMatchedData}; // intentionally don't export variants
 pub use self::util::elaborate_predicates;
+pub use self::util::get_vtable_index_of_object_method;
 pub use self::util::trait_ref_for_builtin_bound;
 pub use self::util::supertraits;
 pub use self::util::Supertraits;
 pub use self::util::transitive_bounds;
+pub use self::util::upcast;
 
 mod coherence;
 mod error_reporting;
 mod fulfill;
 mod project;
+mod object_safety;
 mod select;
 mod util;
 
@@ -212,6 +219,9 @@ pub enum Vtable<'tcx, N> {
     /// for some type parameter.
     VtableParam,
 
+    /// Virtual calls through an object
+    VtableObject(VtableObjectData<'tcx>),
+
     /// Successful resolution for a builtin trait.
     VtableBuiltin(VtableBuiltinData<N>),
 
@@ -247,6 +257,13 @@ pub struct VtableBuiltinData<N> {
     pub nested: subst::VecPerParamSpace<N>
 }
 
+/// A vtable for some object-safe trait `Foo` automatically derived
+/// for the object type `Foo`.
+#[deriving(PartialEq,Eq,Clone)]
+pub struct VtableObjectData<'tcx> {
+    pub object_ty: Ty<'tcx>,
+}
+
 /// True if there exist types that satisfy both of the two given impls.
 pub fn overlapping_impls(infcx: &InferCtxt,
                          impl1_def_id: ast::DefId,
@@ -358,6 +375,7 @@ impl<'tcx, N> Vtable<'tcx, N> {
             VtableFnPointer(..) => (&[]).iter(),
             VtableUnboxedClosure(..) => (&[]).iter(),
             VtableParam => (&[]).iter(),
+            VtableObject(_) => (&[]).iter(),
             VtableBuiltin(ref i) => i.iter_nested(),
         }
     }
@@ -368,6 +386,7 @@ impl<'tcx, N> Vtable<'tcx, N> {
             VtableFnPointer(ref sig) => VtableFnPointer((*sig).clone()),
             VtableUnboxedClosure(d, ref s) => VtableUnboxedClosure(d, s.clone()),
             VtableParam => VtableParam,
+            VtableObject(ref p) => VtableObject(p.clone()),
             VtableBuiltin(ref b) => VtableBuiltin(b.map_nested(op)),
         }
     }
@@ -380,6 +399,7 @@ impl<'tcx, N> Vtable<'tcx, N> {
             VtableFnPointer(sig) => VtableFnPointer(sig),
             VtableUnboxedClosure(d, s) => VtableUnboxedClosure(d, s),
             VtableParam => VtableParam,
+            VtableObject(p) => VtableObject(p),
             VtableBuiltin(no) => VtableBuiltin(no.map_move_nested(op)),
         }
     }