diff --git a/bool/bool.mbt b/bool/bool.mbt
index 9cda9761..abe40a73 100644
--- a/bool/bool.mbt
+++ b/bool/bool.mbt
@@ -22,25 +22,25 @@ pub fn to_int(self : Bool) -> Int {
 
 pub fn to_int64(self : Bool) -> Int64 {
   if self {
-    1L
+    1
   } else {
-    0L
+    0
   }
 }
 
 pub fn to_uint(self : Bool) -> UInt {
   if self {
-    1U
+    1
   } else {
-    0U
+    0
   }
 }
 
 pub fn to_uint64(self : Bool) -> UInt64 {
   if self {
-    1UL
+    1
   } else {
-    0UL
+    0
   }
 }
 
diff --git a/builtin/json.mbt b/builtin/json.mbt
index c9d4a4b7..07956105 100644
--- a/builtin/json.mbt
+++ b/builtin/json.mbt
@@ -29,9 +29,9 @@ pub trait ToJson {
 
 pub fn Bool::to_json(self : Bool) -> Json {
   if self {
-    True
+    true
   } else {
-    False
+    false
   }
 }
 
diff --git a/json/to_json_test.mbt b/json/to_json_test.mbt
index 9fe5af51..a02d6427 100644
--- a/json/to_json_test.mbt
+++ b/json/to_json_test.mbt
@@ -144,29 +144,19 @@ test "Option::to_json" {
   )
 }
 
-// test "optinal field" {
-//   let opt = { x: Some(42), t: Some(Some(42)) }
-//   inspect!(
-//     opt.to_json(),
-//     content=
-//       #|Object({"x": Array([Number(42)]), "t": Array([Array([Number(42)])])})
-//     ,
-//   )
-//   let opt = { x: None, t: None }
-//   inspect!(
-//     opt.to_json(),
-//     content=
-//       #|Object({"x": Null, "t": Null})
-//     ,
-//   )
-//   let opt = { x: None, t: Some(None) }
-//   inspect!(
-//     opt.to_json(),
-//     content=
-//       #|Object({"x": Null, "t": Array([Null])})
-//     ,
-//   )
-// }
+test "optional field" {
+  let opt = [
+    { x: Some(42), t: Some(Some(42)) },
+    { x: None, t: None },
+    { x: None, t: Some(None) },
+  ]
+  inspect!(
+    opt.to_json() |> @json.stringify,
+    content=
+      #|[{"x":42,"t":[42]},{},{"t":null}]
+    ,
+  )
+}
 
 test "optional field round trip" {
   let opt = { x: Some(42), t: Some(Some(42)) }
diff --git a/rational/rational_test.mbt b/rational/rational_test.mbt
index cd59b4a9..f57d1f9b 100644
--- a/rational/rational_test.mbt
+++ b/rational/rational_test.mbt
@@ -107,9 +107,9 @@ test "from_double array" {
   let a : Array[Double] = [
     0.5, 5, 29.97, -29.97, 63.5, 126.5, 127.0, 127.5, -63.5, -126.5, -127.0, -127.5,
   ]
-  inspect_double_array!(
-    a,
-    content="[Ok(1/2), Ok(5), Ok(2997/100), Ok(-2997/100), Ok(127/2), Ok(253/2), Ok(127), Ok(255/2), Ok(-127/2), Ok(-253/2), Ok(-127), Ok(-255/2)]",
+  inspect!(
+    a.map(fn { x => @rational.from_double?(x).unwrap() }),
+    content="[1/2, 5, 2997/100, -2997/100, 127/2, 253/2, 127, 255/2, -127/2, -253/2, -127, -255/2]",
   )
   let a = [
     -10.0e200, 10.0e200, @double.infinity, @double.neg_infinity, @double.not_a_number,