diff --git a/serde/cbor/deserializer.nim b/serde/cbor/deserializer.nim
index 3d406f9..3d08e41 100644
--- a/serde/cbor/deserializer.nim
+++ b/serde/cbor/deserializer.nim
@@ -88,9 +88,9 @@ proc nextUInt*(c: var CborParser): ?!BiggestUInt =
   if c.kind != CborEventKind.cborPositive:
     return failure(newCborError("Expected positive integer, got " & $c.kind))
   let val = c.intVal.BiggestUInt
-  let nextRes = c.next()
-  if nextRes.isFailure:
-    return failure(nextRes.error)
+
+  ?c.next()
+
   return success(val)
 
 
@@ -105,9 +105,7 @@ proc nextInt*(c: var CborParser): ?!BiggestInt =
   else:
     return failure(newCborError("Expected integer, got " & $c.kind))
 
-  let nextRes = c.next()
-  if nextRes.isFailure:
-    return failure(nextRes.error)
+  ?c.next()
 
   return success(val)
 
@@ -126,9 +124,7 @@ proc nextFloat*(c: var CborParser): ?!float64 =
   else:
     discard
 
-  let nextRes = c.next()
-  if nextRes.isFailure:
-    return failure(nextRes.error)
+  ?c.next()
 
   return success(val)
 
@@ -498,31 +494,31 @@ proc parseTime(n: CborNode): Time =
   else:
     assert false
 
-proc fromCborHook*(v: var DateTime; n: CborNode): bool =
+proc fromCborHook*(v: var DateTime; n: CborNode): ?!void =
   ## Parse a `DateTime` from the tagged string representation
   ## defined in RCF7049 section 2.4.1.
   if n.tag.isSome:
     try:
       if n.tag.get == 0 and n.kind == cborText:
         v = parseDateText(n)
-        result = true
+        return success()
       elif n.tag.get == 1 and n.kind in {cborUnsigned, cborNegative, cborFloat}:
         v = parseTime(n).utc
-        result = true
-    except ValueError: discard
+        return success()
+    except ValueError as e: return failure(e)
 
-proc fromCborHook*(v: var Time; n: CborNode): bool =
+proc fromCborHook*(v: var Time; n: CborNode): ?!void =
   ## Parse a `Time` from the tagged string representation
   ## defined in RCF7049 section 2.4.1.
   if n.tag.isSome:
     try:
       if n.tag.get == 0 and n.kind == cborText:
         v = parseDateText(n).toTime
-        result = true
+        return success()
       elif n.tag.get == 1 and n.kind in {cborUnsigned, cborNegative, cborFloat}:
         v = parseTime(n)
-        result = true
-    except ValueError: discard
+        return success()
+    except ValueError as e: return failure(e)
 
 func isTagged*(n: CborNode): bool =
   ## Check if a CBOR item has a tag.
diff --git a/serde/cbor/serializer.nim b/serde/cbor/serializer.nim
index 4165547..294b2ce 100644
--- a/serde/cbor/serializer.nim
+++ b/serde/cbor/serializer.nim
@@ -119,7 +119,7 @@ proc writeCbor*[T](str: Stream; v: T): ?!void =
   try:
     when T is CborNode:
       if v.tag.isSome:
-        return str.writeCborTag(v.tag.get)
+        ?str.writeCborTag(v.tag.get)
       case v.kind:
       of cborUnsigned:
         return str.writeCbor(v.uint)
@@ -158,7 +158,7 @@ proc writeCbor*[T](str: Stream; v: T): ?!void =
       of cborRaw:
         str.write(v.raw)
     elif compiles(writeCborHook(str, v)):
-      writeCborHook(str, v)
+      ?writeCborHook(str, v)
     elif T is SomeUnsignedInt:
       ?str.writeInitial(0, v)
     elif T is SomeSignedInt:
@@ -231,7 +231,6 @@ proc writeCbor*[T](str: Stream; v: T): ?!void =
             var be: float64
             swapEndian64 be.addr, v.unsafeAddr
             str.write be
-
         return success()
       of fcZero:
         str.write initialByte(7, 25)
@@ -262,6 +261,7 @@ proc writeCborArray*(str: Stream; args: varargs[CborNode, toCbor]): ?!void =
   ?str.writeCborArrayLen(args.len)
   for x in args:
     ?str.writeCbor(x)
+  success()
 
 proc encode*[T](v: T): ?!string =
   ## Encode an arbitrary value to CBOR binary representation.
@@ -313,12 +313,14 @@ proc writeCborHook*(str: Stream; dt: DateTime): ?!void =
   ## defined in RCF7049 section 2.4.1.
   ?writeCborTag(str, 0)
   ?writeCbor(str, format(dt, timeFormat))
+  success()
 
 proc writeCborHook*(str: Stream; t: Time): ?!void =
   ## Write a `Time` using the tagged numerical representation
   ## defined in RCF7049 section 2.4.1.
   ?writeCborTag(str, 1)
   ?writeCbor(str, t.toUnix)
+  success()
 
 func toCbor*(x: CborNode): ?!CborNode = success(x)
 
diff --git a/tests/cbor/testprimitives.nim b/tests/cbor/testprimitives.nim
index 0cf988c..a3e4ae7 100644
--- a/tests/cbor/testprimitives.nim
+++ b/tests/cbor/testprimitives.nim
@@ -54,7 +54,8 @@ suite "roundtrip":
       without c =? parseCbor(controlCbor), error:
         fail()
       test name:
-        let testCbor = encode(c)
+        without testCbor =? encode(c), error:
+          fail()
         if controlCbor != testCbor:
           let testB64 = base64.encode(testCbor)
           check(controlB64 == testB64)
@@ -62,42 +63,44 @@ suite "roundtrip":
 suite "hooks":
   test "DateTime":
     let dt = now()
-    var
-      bin = encode(dt)
+
+    without bin =? encode(dt), error:
+      fail()
     without node =? parseCbor(bin), error:
       fail()
     check(node.text == $dt)
   test "Time":
     let t = now().toTime
     var
-      bin = encode(t)
+      bin = encode(t).tryValue
     without node =? parseCbor(bin), error:
       fail()
 
     check(node.getInt == t.toUnix)
 
 test "tag":
-  var c = toCbor("foo")
+  var c = toCbor("foo").tryValue
   c.tag = some(99'u64)
   check c.tag == some(99'u64)
 
 test "sorting":
   var map = initCborMap()
   var keys = @[
-      toCbor(10),
-      toCbor(100),
-      toCbor(-1),
-      toCbor("z"),
-      toCbor("aa"),
-      toCbor([toCbor(100)]),
-      toCbor([toCbor(-1)]),
-      toCbor(false),
+      toCbor(10).tryValue,
+      toCbor(100).tryValue,
+      toCbor(-1).tryValue,
+      toCbor("z").tryValue,
+      toCbor("aa").tryValue,
+      toCbor([toCbor(100).tryValue]).tryValue,
+      toCbor([toCbor(-1).tryValue]).tryValue,
+      toCbor(false).tryValue,
     ]
   shuffle(keys)
-  for k in keys: map[k] = toCbor(0)
-  check not map.isSorted
-  sort(map)
-  check map.isSorted
+  for k in keys: map[k] = toCbor(0).tryValue
+
+  check not map.isSorted.tryValue
+  check sort(map).isSuccess
+  check map.isSorted.tryValue
 
 test "invalid wire type":
   var intValue: int