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discard """
errormsg: "'=' is not available for type <Foo>; requires a copy because it's not the last read of 'otherTree'"
line: 29
"""
type
Foo = object
x: int
proc `=destroy`(f: var Foo) = f.x = 0
proc `=`(a: var Foo; b: Foo) {.error.} # = a.x = b.x
proc `=sink`(a: var Foo; b: Foo) = a.x = b.x
proc createTree(x: int): Foo =
Foo(x: x)
proc take2(a, b: sink Foo) =
echo a.x, " ", b.x
proc allowThis() =
# all these temporary lets are harmless:
let otherTree = createTree(44)
let b = otherTree
let c = b
take2(createTree(34), c)
proc preventThis() =
let otherTree = createTree(44)
let b = otherTree
take2(createTree(34), otherTree)
allowThis()
preventThis()
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