1 files changed, 38 insertions, 0 deletions
diff --git a/tests/ui/consts/const-eval/union-const-eval-field.rs b/tests/ui/consts/const-eval/union-const-eval-field.rs
new file mode 100644
index 000000000..a94fcbbfa
--- /dev/null
+++ b/tests/ui/consts/const-eval/union-const-eval-field.rs
@@ -0,0 +1,38 @@
+// only-x86_64
+
+type Field1 = i32;
+type Field2 = f32;
+type Field3 = i64;
+
+#[repr(C)]
+union DummyUnion {
+    field1: Field1,
+    field2: Field2,
+    field3: Field3,
+}
+
+const FLOAT1_AS_I32: i32 = 1065353216;
+const UNION: DummyUnion = DummyUnion { field1: FLOAT1_AS_I32 };
+
+const fn read_field1() -> Field1 {
+    const FIELD1: Field1 = unsafe { UNION.field1 };
+    FIELD1
+}
+
+const fn read_field2() -> Field2 {
+    const FIELD2: Field2 = unsafe { UNION.field2 };
+    FIELD2
+}
+
+const fn read_field3() -> Field3 {
+    const FIELD3: Field3 = unsafe { UNION.field3 };
+    //~^ ERROR evaluation of constant value failed
+    //~| uninitialized
+    FIELD3
+}
+
+fn main() {
+    assert_eq!(read_field1(), FLOAT1_AS_I32);
+    assert_eq!(read_field2(), 1.0);
+    assert_eq!(read_field3(), unsafe { UNION.field3 });
+}