diff --git a/src/interpreter.rs b/src/interpreter.rs
index c8e73e9fb229..6f559e97688e 100644
--- a/src/interpreter.rs
+++ b/src/interpreter.rs
@@ -269,9 +269,9 @@ impl<'a, 'tcx: 'a> Interpreter<'a, 'tcx> {
         self.memory.write_int(dest, n)
     }
 
-    fn assign_to_product(&mut self, dest: Pointer, dest_repr: Repr,
+    fn assign_to_product(&mut self, dest: Pointer, dest_repr: &Repr,
                          operands: &[mir::Operand<'tcx>]) -> EvalResult<()> {
-        match dest_repr {
+        match *dest_repr {
             Repr::Product { ref fields, .. } => {
                 for (field, operand) in fields.iter().zip(operands) {
                     let src = try!(self.operand_to_ptr(operand));
@@ -315,32 +315,26 @@ impl<'a, 'tcx: 'a> Interpreter<'a, 'tcx> {
             Aggregate(ref kind, ref operands) => {
                 use rustc::mir::repr::AggregateKind::*;
                 match *kind {
-                    Tuple => self.assign_to_product(dest, dest_repr, operands),
+                    Tuple => self.assign_to_product(dest, &dest_repr, operands),
 
-                    Adt(ref adt_def, variant_idx, _) => {
-                        use rustc::middle::ty::AdtKind::*;
-                        match adt_def.adt_kind() {
-                            Struct => self.assign_to_product(dest, dest_repr, operands),
+                    Adt(ref adt_def, variant_idx, _) => match adt_def.adt_kind() {
+                        ty::AdtKind::Struct => self.assign_to_product(dest, &dest_repr, operands),
 
-                            Enum => unimplemented!(),
+                        ty::AdtKind::Enum => match dest_repr {
+                            Repr::Sum { discr_size, ref variants, .. } =>
+                                // TODO(tsion): Write the discriminant value.
+                                self.assign_to_product(
+                                    dest.offset(discr_size),
+                                    &variants[variant_idx],
+                                    operands
+                                ),
+                            _ => panic!("expected Repr::Sum target"),
                         }
-                    }
+                    },
 
                     Vec => unimplemented!(),
                     Closure(..) => unimplemented!(),
                 }
-
-                // let max_fields = adt_def.variants
-                //     .iter()
-                //     .map(|v| v.fields.len())
-                //     .max()
-                //     .unwrap_or(0);
-                // let ptr = self.allocate_aggregate(max_fields);
-                // for (i, operand) in operands.iter().enumerate() {
-                //     let val = self.operand_to_ptr(operand);
-                //     self.write_pointer(ptr.offset(i), val);
-                // }
-                // Value::Adt { variant: variant, data_ptr: ptr }
             }
 
             // Ref(_region, _kind, ref lvalue) => {
diff --git a/test/sums.rs b/test/sums.rs
index bb01e64ae047..e6545e81c00b 100644
--- a/test/sums.rs
+++ b/test/sums.rs
@@ -1,34 +1,30 @@
 #![feature(custom_attribute)]
 #![allow(dead_code, unused_attributes)]
 
-// enum MyOption<T> {
-//     Some { data: T },
-//     None,
-// }
-
-// #[miri_run(expected = "Int(13)")]
-// fn match_my_opt_some() -> i32 {
-//     let x = MyOption::Some { data: 13 };
-//     match x {
-//         MyOption::Some { data } => data,
-//         MyOption::None => 42,
-//     }
-// }
-
-// #[miri_run(expected = "Int(42)")]
-// fn match_my_opt_none() -> i32 {
-//     let x = MyOption::None;
-//     match x {
-//         MyOption::Some { data } => data,
-//         MyOption::None => 42,
-//     }
-// }
+#[miri_run]
+fn return_none() -> Option<i64> {
+    None
+}
 
 #[miri_run]
-fn match_opt_some() -> i64 {
-    let x = Some(13);
-    match x {
-        Some(data) => data,
-        None => 42,
-    }
+fn return_some() -> Option<i64> {
+    Some(42)
 }
+
+// #[miri_run]
+// fn match_opt_none() -> i64 {
+//     let x = None,
+//     match x {
+//         Some(data) => data,
+//         None => 42,
+//     }
+// }
+
+// #[miri_run]
+// fn match_opt_some() -> i64 {
+//     let x = Some(13);
+//     match x {
+//         Some(data) => data,
+//         None => 42,
+//     }
+// }