Address review commets

I think I didn't run tests properly - my second call to
select_all_obligations_or_error has made 3 tests fail. However, this is
just an error message change - integer fallback never worked with casts.

src/test/compile-fail/associated-types-incomplete-object.rs

@@ -28,15 +28,15 @@ impl Foo for isize {
 }
 
 pub fn main() {
-    let a = &42 as &Foo<A=usize, B=char>;
+    let a = &42isize as &Foo<A=usize, B=char>;
 
-    let b = &42 as &Foo<A=usize>;
+    let b = &42isize as &Foo<A=usize>;
     //~^ ERROR the value of the associated type `B` (from the trait `Foo`) must be specified
 
-    let c = &42 as &Foo<B=char>;
+    let c = &42isize as &Foo<B=char>;
     //~^ ERROR the value of the associated type `A` (from the trait `Foo`) must be specified
 
-    let d = &42 as &Foo;
+    let d = &42isize as &Foo;
     //~^ ERROR the value of the associated type `A` (from the trait `Foo`) must be specified
     //~| ERROR the value of the associated type `B` (from the trait `Foo`) must be specified
 }

src/test/compile-fail/cast-rfc0401.rs

@@ -65,6 +65,10 @@ fn main()
     let _ = &f as *const f64; //~ ERROR illegal cast
     let _ = fat_v as usize; //~ ERROR through a raw pointer first
 
+    let a : *const str = "hello";
+    let _ = a as *const Foo;
+    //~^ ERROR `core::marker::Sized` is not implemented for the type `str`
+
     // check no error cascade
     let _ = main.f as *const u32; //~ ERROR attempted access of field
 

src/test/compile-fail/destructure-trait-ref.rs

@@ -28,29 +28,29 @@ fn main() {
     // if n > m, it's a type mismatch error.
 
     // n < m
-    let &x = &(&1 as &T);
-    let &x = &&(&1 as &T);
-    let &&x = &&(&1 as &T);
+    let &x = &(&1isize as &T);
+    let &x = &&(&1isize as &T);
+    let &&x = &&(&1isize as &T);
 
     // n == m
-    let &x = &1 as &T;      //~ ERROR type `&T` cannot be dereferenced
-    let &&x = &(&1 as &T);  //~ ERROR type `&T` cannot be dereferenced
-    let box x = box 1 as Box<T>; //~ ERROR the trait `core::marker::Sized` is not implemented
+    let &x = &1isize as &T;      //~ ERROR type `&T` cannot be dereferenced
+    let &&x = &(&1isize as &T);  //~ ERROR type `&T` cannot be dereferenced
+    let box x = box 1isize as Box<T>; //~ ERROR the trait `core::marker::Sized` is not implemented
 
     // n > m
-    let &&x = &1 as &T;
+    let &&x = &1isize as &T;
     //~^ ERROR mismatched types
     //~| expected `T`
     //~| found `&_`
     //~| expected trait T
     //~| found &-ptr
-    let &&&x = &(&1 as &T);
+    let &&&x = &(&1isize as &T);
     //~^ ERROR mismatched types
     //~| expected `T`
     //~| found `&_`
     //~| expected trait T
     //~| found &-ptr
-    let box box x = box 1 as Box<T>;
+    let box box x = box 1isize as Box<T>;
     //~^ ERROR mismatched types
     //~| expected `T`
     //~| found `Box<_>`

src/test/compile-fail/issue-17458.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 static X: usize = 0 as *const usize as usize;
-//~^ ERROR: can not cast a pointer to an integer in statics
+//~^ ERROR: can't cast a pointer to an integer in statics
 
 fn main() {
     assert_eq!(X, 0);

src/test/compile-fail/issue-5153.rs

@@ -17,6 +17,6 @@ impl Foo for isize {
 }
 
 fn main() {
-    (&5 as &Foo).foo();
+    (&5isize as &Foo).foo();
     //~^ ERROR: no method named `foo` found for type `&Foo` in the current scope
 }

src/test/compile-fail/kindck-impl-type-params.rs

@@ -28,7 +28,6 @@ fn f<T>(val: T) {
     let a = &t as &Gettable<T>;
     //~^ ERROR the trait `core::marker::Send` is not implemented
     //~^^ ERROR the trait `core::marker::Copy` is not implemented
-    //~^^^ ERROR the parameter type `T` may not live long enough
 }
 
 fn g<T>(val: T) {

src/test/run-pass/cast-rfc0401-vtable-kinds.rs

@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// Check that you can cast between different pointers to trait objects
+// whose vtable have the same kind (both lengths, or both trait pointers).
+
 trait Foo<T> {
     fn foo(&self, _: T) -> u32 { 42 }
 }