check built-in types for well-formedness

Fixes rust-lang#21111.
Fixes rust-lang#24707.
Fixes rust-lang#24957.
Fixes rust-lang#25388.
Fixes rust-lang#25637.
Fixes rust-lang#26301.

Author: Ariel Ben-Yehuda

src/librustc_typeck/check/wf.rs

@@ -538,6 +538,10 @@ impl<'cx,'tcx> BoundsChecker<'cx,'tcx> {
         ty.fold_with(self);
         self.binding_count -= 1;
     }
+
+    fn cause(&self, code: traits::ObligationCauseCode<'tcx>) -> traits::ObligationCause<'tcx> {
+        traits::ObligationCause::new(self.span, self.fcx.body_id, code)
+    }
 }
 
 impl<'cx,'tcx> TypeFolder<'tcx> for BoundsChecker<'cx,'tcx> {
@@ -574,7 +578,22 @@ impl<'cx,'tcx> TypeFolder<'tcx> for BoundsChecker<'cx,'tcx> {
             None => { }
         }
 
-        match t.sty{
+        match t.sty {
+            ty::TyArray(ety, _) | ty::TySlice(ety) => {
+                self.fcx.register_builtin_bound(self.fold_ty(ety),
+                                                ty::BoundSized,
+                                                self.cause(traits::MiscObligation));
+                t
+            }
+            ty::TyTuple(ref tys) => {
+                for ty in tys {
+                    self.fcx.register_builtin_bound(self.fold_ty(ty),
+                                                    ty::BoundSized,
+                                                    self.cause(traits::MiscObligation)
+                                                    );
+                }
+                t
+            }
             ty::TyStruct(type_id, substs) |
             ty::TyEnum(type_id, substs) => {
                 let type_predicates = self.fcx.tcx().lookup_predicates(type_id);
@@ -583,9 +602,7 @@ impl<'cx,'tcx> TypeFolder<'tcx> for BoundsChecker<'cx,'tcx> {
 
                 if self.binding_count == 0 {
                     self.fcx.add_obligations_for_parameters(
-                        traits::ObligationCause::new(self.span,
-                                                     self.fcx.body_id,
-                                                     traits::ItemObligation(type_id)),
+                        self.cause(traits::ItemObligation(type_id)),
                         &bounds);
                 } else {
                     // There are two circumstances in which we ignore
@@ -612,20 +629,17 @@ impl<'cx,'tcx> TypeFolder<'tcx> for BoundsChecker<'cx,'tcx> {
                     // that will require an RFC. -nmatsakis)
                     let bounds = filter_to_trait_obligations(bounds);
                     self.fcx.add_obligations_for_parameters(
-                        traits::ObligationCause::new(self.span,
-                                                     self.fcx.body_id,
-                                                     traits::ItemObligation(type_id)),
+                        self.cause(traits::ItemObligation(type_id)),
                         &bounds);
                 }
 
                 self.fold_substs(substs);
+                t
             }
             _ => {
-                super_fold_ty(self, t);
+                super_fold_ty(self, t)
             }
         }
-
-        t // we're not folding to produce a new type, so just return `t` here
     }
 }
 

src/test/compile-fail/associated-types-coherence-failure.rs

@@ -14,7 +14,7 @@
 use std::marker::PhantomData;
 use std::ops::Deref;
 
-pub struct Cow<'a, B: ?Sized>(PhantomData<(&'a (),B)>);
+pub struct Cow<'a, B: ?Sized>(PhantomData<(&'a (),*mut B)>);
 
 /// Trait for moving into a `Cow`
 pub trait IntoCow<'a, B: ?Sized> {

src/test/compile-fail/issue-24957.rs

@@ -0,0 +1,23 @@
+// Copyright 2015 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.
+
+pub enum BsonValue {
+    A([u8]),
+    B([BsonValue]), //~ ERROR the trait `core::marker::Sized` is not implemented
+    //~^ ERROR the trait `core::marker::Sized` is not implemented
+}
+
+pub fn set_value(_v:&BsonValue)
+{
+}
+
+fn main()
+{
+}

src/test/compile-fail/unsized6.rs

@@ -14,13 +14,10 @@ trait T {}
 
 fn f1<X: ?Sized>(x: &X) {
     let _: X; // <-- this is OK, no bindings created, no initializer.
-    let _: (isize, (X, isize)); // same
     let y: X; //~ERROR the trait `core::marker::Sized` is not implemented
-    let y: (isize, (X, isize)); //~ERROR the trait `core::marker::Sized` is not implemented
 }
 fn f2<X: ?Sized + T>(x: &X) {
     let y: X; //~ERROR the trait `core::marker::Sized` is not implemented
-    let y: (isize, (X, isize)); //~ERROR the trait `core::marker::Sized` is not implemented
 }
 
 fn f3<X: ?Sized>(x1: Box<X>, x2: Box<X>, x3: Box<X>) {

src/test/compile-fail/wf-non-well-formed.rs

@@ -0,0 +1,36 @@
+// Copyright 2015 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.
+
+// Check that we catch attempts to create non-well-formed types
+
+struct Bad<T:?Sized+'static, U:?Sized> {
+    p1: &'static [T], //~ ERROR the trait `core::marker::Sized` is not implemented
+    p2: U, //~ ERROR the trait `core::marker::Sized` is not implemented
+    p3: u32
+}
+
+trait Tr {}
+
+struct S<T: Tr>(T);
+
+fn b1() -> &'static [(u8,fn(&'static [S<()>]))]
+{} //~^ ERROR the trait `Tr` is not implemented
+fn b2() -> &'static [[i8]]
+{} //~^ ERROR the trait `core::marker::Sized` is not implemented
+fn b3() -> &'static [[u16]; 2]
+{} //~^ ERROR the trait `core::marker::Sized` is not implemented
+fn b4() -> &'static ([i16],)
+{} //~^ ERROR the trait `core::marker::Sized` is not implemented
+fn b5() -> &'static (u32,[i32],u32)
+{} //~^ ERROR the trait `core::marker::Sized` is not implemented
+fn b6() -> &'static (u32,u32,[i64])
+{} //~^ ERROR the trait `core::marker::Sized` is not implemented
+
+fn main() {}

src/test/compile-fail/wf-specific-sized-where-clause.rs

@@ -0,0 +1,18 @@
+// Copyright 2015 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 Wrap<'a, T: ?Sized>(&'a (), T);
+
+fn foo<'a, T>(_a: for<'s> fn() -> [Wrap<'s, T>]) where Wrap<'a, T>: Sized {
+    //~^ ERROR mismatched types
+    //~^^ ERROR mismatched types
+}
+
+fn main() {}