diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 88c5c38172a..b8d8e6ad0a1 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -543,7 +543,7 @@ impl<T: ?Sized> Drop for Rc<T> {
         unsafe {
             let ptr = *self._ptr;
             if !(*(&ptr as *const _ as *const *const ())).is_null() &&
-               ptr as usize != mem::POST_DROP_USIZE {
+               ptr as *const () as usize != mem::POST_DROP_USIZE {
                 self.dec_strong();
                 if self.strong() == 0 {
                     // destroy the contained object
@@ -1051,7 +1051,7 @@ impl<T: ?Sized> Drop for Weak<T> {
         unsafe {
             let ptr = *self._ptr;
             if !(*(&ptr as *const _ as *const *const ())).is_null() &&
-               ptr as usize != mem::POST_DROP_USIZE {
+               ptr as *const () as usize != mem::POST_DROP_USIZE {
                 self.dec_weak();
                 // the weak count starts at 1, and will only go to zero if all
                 // the strong pointers have disappeared.
diff --git a/src/librustc_trans/trans/expr.rs b/src/librustc_trans/trans/expr.rs
index a65d4225a1f..e5c9a818183 100644
--- a/src/librustc_trans/trans/expr.rs
+++ b/src/librustc_trans/trans/expr.rs
@@ -2048,9 +2048,8 @@ fn trans_imm_cast<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
         } else { llsrc };
     }
 
-    let _icx = push_ctxt("trans_cast");
-    let mut bcx = bcx;
-    let ccx = bcx.ccx();
+    let _icx = push_ctxt("trans_cast"); let mut bcx = bcx; let ccx =
+    bcx.ccx();
 
     let t_in = expr_ty_adjusted(bcx, expr);
     let t_out = node_id_type(bcx, id);
@@ -2080,7 +2079,9 @@ fn trans_imm_cast<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
         } else {
             // Return the address
             return immediate_rvalue_bcx(bcx,
-                                        Load(bcx, get_dataptr(bcx, datum.val)),
+                                        PointerCast(bcx,
+                                                    Load(bcx, get_dataptr(bcx, datum.val)),
+                                                    ll_t_out),
                                         t_out).to_expr_datumblock();
         }
     }
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index d3cf9ae6dff..d5e3139016f 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -528,6 +528,9 @@ fn check_bare_fn<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
             upvar::closure_analyze_fn(&fcx, fn_id, decl, body);
             fcx.select_all_obligations_or_error();
             fcx.check_casts();
+
+            fcx.select_all_obligations_or_error(); // Casts can introduce new obligations.
+
             regionck::regionck_fn(&fcx, fn_id, fn_span, decl, body);
             writeback::resolve_type_vars_in_fn(&fcx, decl, body);
         }
diff --git a/src/test/compile-fail/cast-rfc0401.rs b/src/test/compile-fail/cast-rfc0401.rs
index 3aa866677a8..69ef5421377 100644
--- a/src/test/compile-fail/cast-rfc0401.rs
+++ b/src/test/compile-fail/cast-rfc0401.rs
@@ -56,7 +56,8 @@ fn main()
 
     let _ = 42usize as *const [u8]; //~ ERROR illegal cast
     let _ = v as *const [u8]; //~ ERROR illegal cast
-    let _ = fat_v as *const Foo; //~ ERROR illegal cast
+    let _ = fat_v as *const Foo;
+    //~^ ERROR `core::marker::Sized` is not implemented for the type `[u8]`
     let _ = foo as *const str; //~ ERROR illegal cast
     let _ = foo as *mut str; //~ ERROR illegal cast
     let _ = main as *mut str; //~ ERROR illegal cast
diff --git a/src/test/compile-fail/fat-ptr-cast.rs b/src/test/compile-fail/fat-ptr-cast.rs
index f6633547a7b..25cab09b7cb 100644
--- a/src/test/compile-fail/fat-ptr-cast.rs
+++ b/src/test/compile-fail/fat-ptr-cast.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+trait Trait {}
+
 // Make sure casts between thin-pointer <-> fat pointer obey RFC401
 fn main() {
     let a: &[i32] = &[1, 2, 3];
@@ -17,7 +19,7 @@ fn main() {
 
     a as usize; //~ ERROR illegal cast
     b as usize; //~ ERROR non-scalar cast
-    p as usize; //~ ERROR illegal cast
+    p as usize; //~ ERROR illegal cast; cast through a raw pointer
 
     // #22955
     q as *const [i32]; //~ ERROR illegal cast
diff --git a/src/test/run-pass/cast-rfc0401.rs b/src/test/run-pass/cast-rfc0401.rs
index 92fc2f846ba..ec4c84a1a6b 100644
--- a/src/test/run-pass/cast-rfc0401.rs
+++ b/src/test/run-pass/cast-rfc0401.rs
@@ -85,7 +85,9 @@ fn main()
     assert_eq!(w as usize, lsz);
 
     // ptr-ptr-cast (fat->thin)
-    let u: *const [u8] = unsafe{&*p};    assert_eq!(u as *const u8, p as *const u8);
+    let u: *const [u8] = unsafe{&*p};
+    assert_eq!(u as *const u8, p as *const u8);
+    assert_eq!(u as *const u16, p as *const u16);
 
     // ptr-ptr-cast (both vk=Length)
     let mut l : [u8; 2] = [0,1];
diff --git a/src/test/run-pass/fat-ptr-cast.rs b/src/test/run-pass/fat-ptr-cast.rs
index b7513da99c8..91637d111fe 100644
--- a/src/test/run-pass/fat-ptr-cast.rs
+++ b/src/test/run-pass/fat-ptr-cast.rs
@@ -32,13 +32,12 @@ fn main() {
     // Test conversion to an address (usize).
     let a: *const [i32; 3] = &[1, 2, 3];
     let b: *const [i32] = a;
-    assert!(a as usize == b as usize);
+    assert!(a as usize == b as *const () as usize);
 
     // And conversion to a void pointer/address for trait objects too.
     let a: *mut Foo = &mut Bar;
     let b = a as *mut ();
-    let c = a as usize;
-
+    let c = a as *const () as usize;
     let d = unsafe {
         let r: raw::TraitObject = mem::transmute(a);
         r.data
@@ -46,4 +45,5 @@ fn main() {
 
     assert!(b == d);
     assert!(c == d as usize);
+
 }