From f49a96501d4f11cb08c382bd8180a5a5db59213d Mon Sep 17 00:00:00 2001
From: Ilija Tovilo <ilija.tovilo@me.com>
Date: Wed, 24 Jul 2019 14:09:26 +0200
Subject: [PATCH] Add test for #51559

Closes #51559
---
 src/test/ui/consts/issue-51559.rs     |  7 +++++++
 src/test/ui/consts/issue-51559.stderr | 11 +++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 src/test/ui/consts/issue-51559.rs
 create mode 100644 src/test/ui/consts/issue-51559.stderr

diff --git a/src/test/ui/consts/issue-51559.rs b/src/test/ui/consts/issue-51559.rs
new file mode 100644
index 0000000000000..429947269385b
--- /dev/null
+++ b/src/test/ui/consts/issue-51559.rs
@@ -0,0 +1,7 @@
+#![feature(const_raw_ptr_to_usize_cast)]
+
+const BAR: *mut () = ((|| 3) as fn() -> i32) as *mut ();
+pub const FOO: usize = unsafe { BAR as usize };
+//~^ ERROR it is undefined behavior to use this value
+
+fn main() {}
diff --git a/src/test/ui/consts/issue-51559.stderr b/src/test/ui/consts/issue-51559.stderr
new file mode 100644
index 0000000000000..917c54ddaef1e
--- /dev/null
+++ b/src/test/ui/consts/issue-51559.stderr
@@ -0,0 +1,11 @@
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/issue-51559.rs:4:1
+   |
+LL | pub const FOO: usize = unsafe { BAR as usize };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a pointer, but expected initialized plain (non-pointer) bytes
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0080`.