From 7e1a65dce1d13d02de8e0ffafad15538556cb7b9 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Fri, 20 Sep 2019 13:53:46 +0200
Subject: [PATCH] Ensure we do not treat all unions as not having any drop
 glue.

---
 src/test/ui/union/union-custom-drop.rs     | 19 +++++++++++++++
 src/test/ui/union/union-custom-drop.stderr | 28 ++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 src/test/ui/union/union-custom-drop.rs
 create mode 100644 src/test/ui/union/union-custom-drop.stderr

diff --git a/src/test/ui/union/union-custom-drop.rs b/src/test/ui/union/union-custom-drop.rs
new file mode 100644
index 0000000000000..8f816cc1b737c
--- /dev/null
+++ b/src/test/ui/union/union-custom-drop.rs
@@ -0,0 +1,19 @@
+// test for a union with a field that's a union with a manual impl Drop
+// Ensures we do not treat all unions as not having any drop glue.
+
+#![feature(untagged_unions)]
+
+union Foo {
+    bar: Bar, //~ ERROR unions may not contain fields that need dropping
+}
+
+union Bar {
+    a: i32,
+    b: u32,
+}
+
+impl Drop for Bar {
+    fn drop(&mut self) {}
+}
+
+fn main() {}
diff --git a/src/test/ui/union/union-custom-drop.stderr b/src/test/ui/union/union-custom-drop.stderr
new file mode 100644
index 0000000000000..8e4e5dd40fd3f
--- /dev/null
+++ b/src/test/ui/union/union-custom-drop.stderr
@@ -0,0 +1,28 @@
+error[E0601]: `main` function not found in crate `union_custom_drop`
+  --> $DIR/union-custom-drop.rs:4:1
+   |
+LL | / #![feature(untagged_unions)]
+LL | |
+LL | | union Foo {
+LL | |     bar: Bar,
+...  |
+LL | |     }
+LL | | }
+   | |_^ consider adding a `main` function to `$DIR/union-custom-drop.rs`
+
+error[E0740]: unions may not contain fields that need dropping
+  --> $DIR/union-custom-drop.rs:7:5
+   |
+LL |     bar: Bar,
+   |     ^^^^^^^^
+   |
+note: `std::mem::ManuallyDrop` can be used to wrap the type
+  --> $DIR/union-custom-drop.rs:7:5
+   |
+LL |     bar: Bar,
+   |     ^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0601, E0740.
+For more information about an error, try `rustc --explain E0601`.