```v
 struct Node {
     a &Node
-    b &Node = 0 // Auto-initialized to nil, use with caution!
+    b &Node = unsafe { nil } // Auto-initialized to nil, use with caution!
 }
 
 // Reference fields must be initialized unless an initial value is declared.

 
 struct App {
 mut:
-    gg     &gg.Context = 0
+    gg     &gg.Context = unsafe { nil }
     radius f64 = 10.0
 }
 
 fn frame(mut app App) {
     app.gg.begin()
     app.gg.draw_circle_empty(150, 150, f32(app.radius), gx.blue)
-    app.gg.draw_text(20, 20, 'radius: $app.radius')
+    app.gg.draw_text(20, 20, 'radius: ${app.radius}')
     //    app.gg.draw_text(20, 50, 'circle_segment_size: $circle_segment_size')
     app.gg.end()
 }

 
 struct App {
 mut:
-    tui &tui.Context = 0
+    tui &tui.Context = unsafe { nil }
 }
 
 fn event(e &tui.Event, x voidptr) {

 struct Node[T] {
 pub mut:
     val  T
-    next &Node[T] = 0
+    next &Node[T] = unsafe { nil }
 }
 
 fn new[T]() &Node[T] {

 struct ListNode[T] {
 pub mut:
     val  T
-    next &ListNode[T] = 0
+    next &ListNode[T] = unsafe { nil }
 }
 
 fn (mut node ListNode[T]) test() &ListNode[T] {

 struct List[T] {
 pub mut:
-    head &ListNode[T] = 0
+    head &ListNode[T] = unsafe { nil }
 }
 
 struct ListNode[T] {
 pub mut:
     value T
-    next  &ListNode[T] = 0
+    next  &ListNode[T] = unsafe { nil }
 }
 
 fn list_new[T]() List[T] {

 struct ListNode[T] {
 mut:
     val  T
-    next &ListNode[T] = 0
+    next &ListNode[T] = unsafe { nil }
 }
 
 fn create[T](arr []T) &List[T] {

 
 struct List[T] {
 pub mut:
-    head &ListNode[T] = 0
+    head &ListNode[T] = unsafe { nil }
 }
 
 struct ListNode[T] {
 pub mut:
     value T
-    next  &ListNode[T] = 0
+    next  &ListNode[T] = unsafe { nil }
 }
 
 pub fn list_new[T]() &List[T] {

 struct Node[T] {
 mut:
     data T
-    next &Node[T] = 0
+    next &Node[T] = unsafe { nil }
 }
 
 struct SinglyLinkedList[T] {
 mut:
-    first_node &Node[T] = 0
+    first_node &Node[T] = unsafe { nil }
 }
 
 fn init_singlylinkedlist[T](nodes ...Node[T]) SinglyLinkedList[T] {

 struct Abc {
 mut:
     vptr    voidptr
-    vptrptr &voidptr = 0
-    bptr    &u8      = 0
+    vptrptr &voidptr = unsafe { nil }
+    bptr    &u8      = unsafe { nil }
     cptr    &char    = c'abcdef'
 }