auto merge of #16811 : nick29581/rust/dst-bug-2, r=nikomatsakis

closes #16800 
r? @nikomatsakis - I'm not 100% sure this is the right approach, it is kind of ad-hoc. The trouble is we don't have any intrinsic notion of which types are sized and which are not, we only have the Sized bound, so I have nothing to validate the Sized bound against.

Author: bors

src/librustc/middle/kind.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 use middle::freevars::freevar_entry;
 use middle::freevars;
 use middle::subst;
@@ -587,15 +586,15 @@ fn check_ty(cx: &mut Context, aty: &Ty) {
     match aty.node {
         TyPath(_, _, id) => {
             match cx.tcx.item_substs.borrow().find(&id) {
-                None => { }
+                None => {}
                 Some(ref item_substs) => {
                     let def_map = cx.tcx.def_map.borrow();
                     let did = def_map.get_copy(&id).def_id();
                     let generics = ty::lookup_item_type(cx.tcx, did).generics;
                     for def in generics.types.iter() {
                         let ty = *item_substs.substs.types.get(def.space,
                                                                def.index);
-                        check_typaram_bounds(cx, aty.span, ty, def)
+                        check_typaram_bounds(cx, aty.span, ty, def);
                     }
                 }
             }
@@ -668,7 +667,7 @@ fn check_bounds_on_structs_or_enums_in_type_if_possible(cx: &mut Context,
                                                   .zip(polytype.generics
                                                                .types
                                                                .iter()) {
-                    check_typaram_bounds(cx, span, *ty, type_param_def)
+                    check_typaram_bounds(cx, span, *ty, type_param_def);
                 }
 
                 // Check trait bounds.

src/librustc/middle/ty.rs

@@ -2410,7 +2410,7 @@ pub fn type_contents(cx: &ctxt, ty: t) -> TypeContents {
             }
 
             ty_trait(box ty::TyTrait { bounds, .. }) => {
-                object_contents(cx, bounds) | TC::ReachesFfiUnsafe
+                object_contents(cx, bounds) | TC::ReachesFfiUnsafe | TC::Nonsized
             }
 
             ty_ptr(ref mt) => {

src/test/compile-fail/bad-sized.rs

@@ -0,0 +1,25 @@
+// Copyright 2012 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.
+
+// ignore-tidy-linelength
+
+use std::cell::RefCell;
+
+trait Trait {}
+
+pub fn main() {
+    let x: Vec<Trait + Sized> = Vec::new();
+    //~^ ERROR instantiating a type parameter with an incompatible type `Trait+Sized`, which does not fulfill `Sized`
+    //~^^ ERROR instantiating a type parameter with an incompatible type `Trait+Sized`, which does not fulfill `Sized`
+    //~^^^ ERROR instantiating a type parameter with an incompatible type `Trait+Sized`, which does not fulfill `Sized`
+    let x: Vec<Box<RefCell<Trait + Sized>>> = Vec::new();
+    //~^ ERROR instantiating a type parameter with an incompatible type `Trait+Sized`, which does not fulfill `Sized`
+    //~^^ ERROR instantiating a type parameter with an incompatible type `Trait+Sized`, which does not fulfill `Sized`
+}