diff --git a/type.go b/type.go
index e464e82..956b3bf 100644
--- a/type.go
+++ b/type.go
@@ -46,7 +46,12 @@ func scalarType(t reflect.Type) Scalar {
 }
 
 func scalarTypeReflect(v any) Scalar {
-	return scalarType(reflect.TypeOf(v))
+	t := reflect.TypeOf(v)
+	if t == nil {
+		return Any
+	}
+
+	return scalarType(t)
 }
 
 func scalarSize(t reflect.Type) int {
@@ -67,7 +72,12 @@ func valueSize(v reflect.Value) int {
 }
 
 func valueSizeReflect(v any) int {
-	return valueSize(reflect.ValueOf(v))
+	r := reflect.ValueOf(v)
+	if hasCircularReference(r) {
+		return 0
+	}
+
+	return valueSize(r)
 }
 
 func setVisited[T comparable](visited map[T]bool, k T) map[T]bool {