1 files changed, 8 insertions, 0 deletions
diff --git a/tests/ui/borrowck/borrowck-use-uninitialized-in-cast.rs b/tests/ui/borrowck/borrowck-use-uninitialized-in-cast.rs
new file mode 100644
index 000000000..a355a546d
--- /dev/null
+++ b/tests/ui/borrowck/borrowck-use-uninitialized-in-cast.rs
@@ -0,0 +1,8 @@
+// Check that we detect unused values that are cast to other things.
+// The problem was specified to casting to `*`, as creating unsafe
+// pointers was not being fully checked. Issue #20791.
+
+fn main() {
+    let x: &i32;
+    let y = x as *const i32; //~ ERROR [E0381]
+}