2 files changed, 38 insertions, 0 deletions
diff --git a/tests/ui/unsafe/union-pat-in-param.rs b/tests/ui/unsafe/union-pat-in-param.rs
new file mode 100644
index 00000000000..8454bfb20dc
--- /dev/null
+++ b/tests/ui/unsafe/union-pat-in-param.rs
@@ -0,0 +1,19 @@
+union U {
+    a: &'static i32,
+    b: usize,
+}
+
+fn fun(U { a }: U) {
+    //~^ ERROR access to union field is unsafe
+    dbg!(*a);
+}
+
+fn main() {
+    fun(U { b: 0 });
+
+    let closure = |U { a }| {
+        //~^ ERROR access to union field is unsafe
+        dbg!(*a);
+    };
+    closure(U { b: 0 });
+}
diff --git a/tests/ui/unsafe/union-pat-in-param.stderr b/tests/ui/unsafe/union-pat-in-param.stderr
new file mode 100644
index 00000000000..b9709b7cc9b
--- /dev/null
+++ b/tests/ui/unsafe/union-pat-in-param.stderr
@@ -0,0 +1,19 @@
+error[E0133]: access to union field is unsafe and requires unsafe function or block
+  --> $DIR/union-pat-in-param.rs:6:12
+   |
+LL | fn fun(U { a }: U) {
+   |            ^ access to union field
+   |
+   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
+
+error[E0133]: access to union field is unsafe and requires unsafe function or block
+  --> $DIR/union-pat-in-param.rs:14:24
+   |
+LL |     let closure = |U { a }| {
+   |                        ^ access to union field
+   |
+   = note: the field may not be properly initialized: using uninitialized data will cause undefined behavior
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0133`.