1 files changed, 16 insertions, 0 deletions
diff --git a/src/test/ui/borrowck/reassignment_immutable_fields_overlapping.rs b/src/test/ui/borrowck/reassignment_immutable_fields_overlapping.rs
new file mode 100644
index 000000000..d7aad6c01
--- /dev/null
+++ b/src/test/ui/borrowck/reassignment_immutable_fields_overlapping.rs
@@ -0,0 +1,16 @@
+// This should never be allowed -- `foo.a` and `foo.b` are
+// overlapping, so since `x` is not `mut` we should not permit
+// reassignment.
+
+union Foo {
+    a: u32,
+    b: u32,
+}
+
+unsafe fn overlapping_fields() {
+    let x: Foo;
+    x.a = 1;  //~ ERROR
+    x.b = 22; //~ ERROR
+}
+
+fn main() { }