unify_types shows up as dead code for some alt! invocations
@@ -198,6 +198,7 @@ macro_rules! alt (
// Compile-time hack to ensure that res's E type is not under-specified.
// This all has no effect at runtime.
+ #[allow(dead_code)]
fn unify_types<T>(_: &T, _: &T) {}
if let Err(Err::Error(ref e2)) = out {
unify_types(&e, e2);
