arc: =deepcopy fixes

tests/arc/tdeepcopy.nim

@@ -0,0 +1,67 @@
+discard """
+  cmd: "nim c --gc:arc $file"
+  output: '''13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+13 abc
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+called deepCopy for int
+0'''
+"""
+
+type
+  PBinaryTree = ref object of RootObj
+    le, ri: PBinaryTree
+    value: int
+
+proc mainB =
+  var x: PBinaryTree
+  deepCopy(x, PBinaryTree(ri: PBinaryTree(le: PBinaryTree(value: 13))))
+
+  var y: string
+  deepCopy y, "abc"
+  echo x.ri.le.value, " ", y
+
+for i in 0..10:
+  mainB()
+
+
+type
+  Bar[T] = object
+    x: T
+
+proc `=deepCopy`[T](b: ref Bar[T]): ref Bar[T] =
+  result.new
+  result.x = b.x
+  when T is int:
+    echo "called deepCopy for int"
+  else:
+    echo "called deepCopy for something else"
+
+proc main =
+  var dummy, c: ref Bar[int]
+  new(dummy)
+  dummy.x = 44
+
+  deepCopy c, dummy
+
+for i in 0..10:
+  main()
+
+echo getOccupiedMem()