add mir-opt test

Author: ashivaram23

compiler/rustc_mir_transform/src/elaborate_drops.rs

@@ -69,6 +69,7 @@ impl<'tcx> crate::MirPass<'tcx> for ElaborateDrops {
             let dead_unwinds = compute_dead_unwinds(body, &mut inits);
 
             let uninits = MaybeUninitializedPlaces::new(tcx, body, &env.move_data)
+                .include_inactive_in_otherwise()
                 .mark_inactive_variants_as_uninit()
                 .skipping_unreachable_unwind(dead_unwinds)
                 .iterate_to_fixpoint(tcx, body, Some("elaborate_drops"))

tests/mir-opt/otherwise_drops.rs

@@ -0,0 +1,13 @@
+//@ test-mir-pass: ElaborateDrops
+
+// EMIT_MIR otherwise_drops.result_ok.ElaborateDrops.after.mir
+fn result_ok(result: Result<String, ()>) -> Option<String> {
+    match result {
+        Ok(s) => Some(s),
+        _ => None,
+    }
+}
+
+fn main() {
+    result_ok(Err(()));
+}