gc:arc memory leak

[khchen]

This code will cause a memory leak if compile with --gc:arc.

Example

type
  Foo = ref object
    data: int
    parent: Foo

proc `=destroy`(self: var type(Foo()[])) =
  echo "destroy foo ", self.data
  for i in self.fields: i.reset

proc getParent(self: Foo): Foo = self.parent

var foo1 = Foo(data: 1)
var foo2 = Foo(data: 2, parent: foo1)

foo2.getParent.data = 1

Current Output

destroy foo 2

Expected Output

destroy foo 2
destroy foo 1

Possible Solution 1

proc getParent(self: Foo): lent Foo = self.parent

Possible Solution 2

var foo = foo2.getParent
foo.data = 1

Additional Information

$ nim -v
Nim Compiler Version 1.1.1 [Windows: amd64]
Compiled at 2020-03-16
Copyright (c) 2006-2019 by Andreas Rumpf

[cooldome]

I have a fix for this bug