1 files changed, 33 insertions, 0 deletions
diff --git a/tests/ui/cast/fat-ptr-cast.rs b/tests/ui/cast/fat-ptr-cast.rs
new file mode 100644
index 000000000..b5276dc61
--- /dev/null
+++ b/tests/ui/cast/fat-ptr-cast.rs
@@ -0,0 +1,33 @@
+trait Trait {}
+
+// Make sure casts between thin-pointer <-> fat pointer obey RFC401
+fn main() {
+    let a: &[i32] = &[1, 2, 3];
+    let b: Box<[i32]> = Box::new([1, 2, 3]);
+    let p = a as *const [i32];
+    let q = a.as_ptr();
+
+    a as usize; //~ ERROR casting
+    a as isize; //~ ERROR casting
+    a as i16; //~ ERROR casting `&[i32]` as `i16` is invalid
+    a as u32; //~ ERROR casting `&[i32]` as `u32` is invalid
+    b as usize; //~ ERROR non-primitive cast
+    p as usize;
+    //~^ ERROR casting
+
+    // #22955
+    q as *const [i32]; //~ ERROR cannot cast
+
+    // #21397
+    let t: *mut (dyn Trait + 'static) = 0 as *mut _;
+    //~^ ERROR cannot cast `usize` to a pointer that is wide
+    let mut fail: *const str = 0 as *const str;
+    //~^ ERROR cannot cast `usize` to a pointer that is wide
+    let mut fail2: *const str = 0isize as *const str;
+    //~^ ERROR cannot cast `isize` to a pointer that is wide
+}
+
+fn foo<T: ?Sized>() {
+    let s = 0 as *const T;
+    //~^ ERROR cannot cast `usize` to a pointer that may be wide
+}