[vm]fixes #15974 #12551 #19464 #16020 #16780 #16613 #14553 #19909 #18641 (#19902) [backport]

* revert #12217 since the root problem seems to have been fixed; fix #15974;fix #12551; fix #19464

* fix #16020; fix #16780

* fix tests and #16613

* fix #14553

* fix #19909; skip skipRegisterAddr

* fix #18641

tests/vm/tissues.nim

@@ -1,6 +1,6 @@
 import macros
 
-block t9043: # issue #9043
+block t9043: # bug #9043
   proc foo[N: static[int]](dims: array[N, int]): string =
     const N1 = N
     const N2 = dims.len
@@ -26,3 +26,51 @@ block t4952:
     let tree = newTree(nnkExprColonExpr)
     let t = (n: tree)
     doAssert: t.n.kind == tree.kind
+
+
+# bug #19909
+type
+  SinglyLinkedList[T] = ref object
+  SinglyLinkedListObj[T] = ref object
+
+
+proc addMoved[T](a, b: var SinglyLinkedList[T]) =
+  if a.addr != b.addr: discard
+
+proc addMoved[T](a, b: var SinglyLinkedListObj[T]) =
+  if a.addr != b.addr: discard
+
+proc main =
+  var a: SinglyLinkedList[int]; new a
+  var b: SinglyLinkedList[int]; new b
+  a.addMoved b
+
+  var a0: SinglyLinkedListObj[int]
+  var b0: SinglyLinkedListObj[int]
+  a0.addMoved b0
+
+static: main()
+
+
+# bug #18641
+
+type A = object
+  ha1: int
+static:
+  var a = A()
+  var a2 = a.addr
+  a2.ha1 = 11
+  doAssert a2.ha1 == 11
+  a.ha1 = 12
+  doAssert a.ha1 == 12
+  doAssert a2.ha1 == 12 # ok
+static:
+  proc fn() =
+    var a = A()
+    var a2 = a.addr
+    a2.ha1 = 11
+    doAssert a2.ha1 == 11
+    a.ha1 = 12
+    doAssert a.ha1 == 12
+    doAssert a2.ha1 == 12 # fails
+  fn()