From 7b7f690274683777e810bfb61aae2af2e36aaab8 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Thu, 22 Jun 2017 17:47:09 -0700
Subject: [PATCH] Make sure that casting a ptr-integer down to u8 makes it
 unusable

---
 tests/compile-fail/ptr_int_cast.rs | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 tests/compile-fail/ptr_int_cast.rs

diff --git a/tests/compile-fail/ptr_int_cast.rs b/tests/compile-fail/ptr_int_cast.rs
new file mode 100644
index 000000000000..b004a18ff465
--- /dev/null
+++ b/tests/compile-fail/ptr_int_cast.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let x = &1;
+    // Casting down to u8 and back up to a pointer loses too much precision; this must not work.
+    let x = x as *const i32 as u8;
+    let x = x as *const i32; //~ ERROR: a raw memory access tried to access part of a pointer value as raw bytes
+    let _ = unsafe { *x };
+}