From 7f92eab3c477f321a55f53b6e04ac8ca2cd04ebf Mon Sep 17 00:00:00 2001
From: David Cook <divergentdave@gmail.com>
Date: Thu, 23 Apr 2020 20:00:25 -0500
Subject: [PATCH] Add test to exercise InvalidUndefBytes

---
 tests/compile-fail/undefined_buffer.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 tests/compile-fail/undefined_buffer.rs

diff --git a/tests/compile-fail/undefined_buffer.rs b/tests/compile-fail/undefined_buffer.rs
new file mode 100644
index 000000000000..dac02a8690e9
--- /dev/null
+++ b/tests/compile-fail/undefined_buffer.rs
@@ -0,0 +1,20 @@
+// error-pattern: reading uninitialized memory
+
+use std::alloc::{alloc, dealloc, Layout};
+use std::slice::from_raw_parts;
+
+fn main() {
+    let layout = Layout::from_size_align(32, 8).unwrap();
+    unsafe {
+        let ptr = alloc(layout);
+        *ptr = 0x41;
+        *ptr.add(1) = 0x42;
+        *ptr.add(2) = 0x43;
+        *ptr.add(3) = 0x44;
+        *ptr.add(16) = 0x00;
+        let slice1 = from_raw_parts(ptr, 16);
+        let slice2 = from_raw_parts(ptr.add(16), 16);
+        drop(slice1.cmp(slice2));
+        dealloc(ptr, layout);
+    }
+}