Consistent underscores in root directory

test_suite/tests/compile-fail/str_ref_deser.rs

@@ -0,0 +1,9 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize, Deserialize)] //~ ERROR: custom derive attribute panicked
+struct Test<'a> {
+    s: &'a str, //~^^ HELP: Serde does not support deserializing fields of type &str
+}
+
+fn main() {}