1 files changed, 24 insertions, 0 deletions
diff --git a/src/test/ui/mir-dataflow/uninits-2.rs b/src/test/ui/mir-dataflow/uninits-2.rs
new file mode 100644
index 000000000..c584ee74a
--- /dev/null
+++ b/src/test/ui/mir-dataflow/uninits-2.rs
@@ -0,0 +1,24 @@
+// General test of maybe_uninits state computed by MIR dataflow.
+
+#![feature(core_intrinsics, rustc_attrs)]
+
+use std::intrinsics::rustc_peek;
+use std::mem::{drop, replace};
+
+struct S(i32);
+
+#[rustc_mir(rustc_peek_maybe_uninit,stop_after_dataflow)]
+fn foo(x: &mut S) {
+    // `x` is initialized here, so maybe-uninit bit is 0.
+
+    rustc_peek(&x); //~ ERROR rustc_peek: bit not set
+
+    ::std::mem::drop(x);
+
+    // `x` definitely uninitialized here, so maybe-uninit bit is 1.
+    rustc_peek(&x);
+}
+fn main() {
+    foo(&mut S(13));
+    foo(&mut S(13));
+}