From f36220212f2a80bedf485149f8babcf607922137 Mon Sep 17 00:00:00 2001
From: Andrew Liu <andrewlliu@gmail.com>
Date: Sun, 20 Dec 2020 11:04:42 -0800
Subject: [PATCH 1/3] impl isobjectref for array

---
 rust/tvm-rt/src/array.rs | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/rust/tvm-rt/src/array.rs b/rust/tvm-rt/src/array.rs
index 1b0ce8399d1f..33dbed4a89e0 100644
--- a/rust/tvm-rt/src/array.rs
+++ b/rust/tvm-rt/src/array.rs
@@ -45,6 +45,26 @@ external! {
     fn array_size(array: ObjectRef) -> i64;
 }
 
+impl<T: IsObjectRef> IsObjectRef for Array<T> {
+    type Object = Object;
+    fn as_ptr(&self) -> Option<&ObjectPtr<Self::Object>> {
+        self.object.as_ptr()
+    }
+    fn into_ptr(self) -> Option<ObjectPtr<Self::Object>> {
+        self.object.into_ptr()
+    }
+    fn from_ptr(object_ptr: Option<ObjectPtr<Self::Object>>) -> Self {
+        let object_ref = match object_ptr {
+          Some(o) => o.into(),
+          _ => panic!()
+        };
+        Array {
+            object: object_ref,
+            _data: PhantomData,
+        }
+    }
+}
+
 impl<T: IsObjectRef> Array<T> {
     pub fn from_vec(data: Vec<T>) -> Result<Array<T>> {
         let iter = data.into_iter().map(T::into_arg_value).collect();
@@ -131,8 +151,8 @@ impl<T: IsObjectRef> FromIterator<T> for Array<T> {
     }
 }
 
-impl<T: IsObjectRef> From<Array<T>> for ArgValue<'static> {
-    fn from(array: Array<T>) -> ArgValue<'static> {
+impl<'a, T: IsObjectRef> From<Array<T>> for ArgValue<'a> {
+    fn from(array: Array<T>) -> ArgValue<'a> {
         array.object.into()
     }
 }

From eeaed3f3e5ae45fc25d95a184221918c9e3ec591 Mon Sep 17 00:00:00 2001
From: Andrew Liu <andrewlliu@gmail.com>
Date: Sun, 20 Dec 2020 11:37:22 -0800
Subject: [PATCH 2/3] array test

---
 rust/tvm-rt/src/array.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/rust/tvm-rt/src/array.rs b/rust/tvm-rt/src/array.rs
index 33dbed4a89e0..f3fbb7558347 100644
--- a/rust/tvm-rt/src/array.rs
+++ b/rust/tvm-rt/src/array.rs
@@ -193,6 +193,7 @@ mod tests {
     use super::Array;
     use crate::function::Result;
     use crate::string::String;
+    use crate::object::{IsObjectRef, ObjectRef};
 
     #[test]
     fn create_array_and_get() -> Result<()> {
@@ -203,4 +204,13 @@ mod tests {
         assert_eq!(array.get(2)?.to_string(), "baz");
         Ok(())
     }
+
+    #[test]
+    fn downcast() -> Result<()> {
+        let vec: Vec<String> = vec!["foo".into(), "bar".into(), "baz".into()];
+        let array: ObjectRef = ObjectRef::from_ptr(Array::from_vec(vec)?.into_ptr());
+        let array: Array<ObjectRef> = array.downcast::<Array<ObjectRef>>().unwrap();
+        assert_eq!(array.get(1)?.downcast::<String>().unwrap(), "bar");
+        Ok(())
+    }
 }

From a9689aad3fc3481bac6aa4acc0ec456f2e568d98 Mon Sep 17 00:00:00 2001
From: Andrew Liu <andrewlliu@gmail.com>
Date: Mon, 21 Dec 2020 15:01:05 -0800
Subject: [PATCH 3/3] cargo fmt

---
 rust/tvm-rt/src/array.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/rust/tvm-rt/src/array.rs b/rust/tvm-rt/src/array.rs
index f3fbb7558347..5abf66708f45 100644
--- a/rust/tvm-rt/src/array.rs
+++ b/rust/tvm-rt/src/array.rs
@@ -55,8 +55,8 @@ impl<T: IsObjectRef> IsObjectRef for Array<T> {
     }
     fn from_ptr(object_ptr: Option<ObjectPtr<Self::Object>>) -> Self {
         let object_ref = match object_ptr {
-          Some(o) => o.into(),
-          _ => panic!()
+            Some(o) => o.into(),
+            _ => panic!(),
         };
         Array {
             object: object_ref,
@@ -192,8 +192,8 @@ impl<'a, T: IsObjectRef> TryFrom<RetValue> for Array<T> {
 mod tests {
     use super::Array;
     use crate::function::Result;
-    use crate::string::String;
     use crate::object::{IsObjectRef, ObjectRef};
+    use crate::string::String;
 
     #[test]
     fn create_array_and_get() -> Result<()> {