1 files changed, 27 insertions, 0 deletions
diff --git a/tests/ui/stdlib-unit-tests/log-knows-the-names-of-variants-in-std.rs b/tests/ui/stdlib-unit-tests/log-knows-the-names-of-variants-in-std.rs
new file mode 100644
index 000000000..c5a40edbe
--- /dev/null
+++ b/tests/ui/stdlib-unit-tests/log-knows-the-names-of-variants-in-std.rs
@@ -0,0 +1,27 @@
+// run-pass
+
+#![allow(non_camel_case_types)]
+#![allow(dead_code)]
+#[derive(Clone, Debug)]
+enum foo {
+  a(usize),
+  b(String),
+}
+
+fn check_log<T: std::fmt::Debug>(exp: String, v: T) {
+    assert_eq!(exp, format!("{:?}", v));
+}
+
+pub fn main() {
+    let mut x = Some(foo::a(22));
+    let exp = "Some(a(22))".to_string();
+    let act = format!("{:?}", x);
+    assert_eq!(act, exp);
+    check_log(exp, x);
+
+    x = None;
+    let exp = "None".to_string();
+    let act = format!("{:?}", x);
+    assert_eq!(act, exp);
+    check_log(exp, x);
+}