Add more array references to raw pointer casts.

src/librustc_typeck/check/cast.rs

@@ -1,4 +1,4 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -20,7 +20,8 @@
 //! * `e` is a C-like enum and `U` is an integer type; *enum-cast*
 //! * `e` has type `bool` or `char` and `U` is an integer; *prim-int-cast*
 //! * `e` has type `u8` and `U` is `char`; *u8-char-cast*
-//! * `e` has type `&[T; n]` and `U` is `*const T`; *array-ptr-cast*
+//! * `e` has type `&.[T; n]` and `U` is `*T`,
+//!   while if `e` is `&[T; n]` then `U` is `*const T`; *array-ptr-cast*
 //! * `e` is a function pointer type and `U` has type `*T`,
 //!   while `T: Sized`; *fptr-ptr-cast*
 //! * `e` is a function pointer type and `U` is an integer; *fptr-addr-cast*
@@ -345,7 +346,7 @@ impl<'tcx> CastCheck<'tcx> {
     {
         // array-ptr-cast.
 
-        if m_expr.mutbl == hir::MutImmutable && m_cast.mutbl == hir::MutImmutable {
+        if  !(m_expr.mutbl == hir::MutImmutable && m_cast.mutbl == hir::MutMutable) {
             if let ty::TyArray(ety, _) = m_expr.ty.sty {
                 // Due to the limitations of LLVM global constants,
                 // region pointers end up pointing at copies of

src/test/compile-fail/cast-mut-ref-to-const-ptr.rs

@@ -0,0 +1,14 @@
+// Copyright 2016 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.
+
+fn main() {
+    let my_num = &[10, 20] as *mut i32;
+    //~ error: casting `&[i32; 2]` as `*mut i32` is invalid
+}

src/test/run-pass/cast.rs

@@ -1,4 +1,4 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 pub fn main() {
     let i: isize = 'Q' as isize;
     assert_eq!(i, 0x51);
@@ -19,4 +18,8 @@ pub fn main() {
     assert_eq!(i as u8 as i8, 'Q' as u8 as i8);
     assert_eq!(0x51 as char, 'Q');
     assert_eq!(0 as u32, false as u32);
+
+    let x = &[10, 20] as *const i32;
+    let y = &mut [10, 20] as *mut i32;
+    let z = &mut [10, 20] as *const i32;
 }