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Some known package-level variable initialization order bugs in certain Go toolchain versions

Case 1

Due to a function inline bug (the function call foo() is inlined here), with Go toolchain versions prior to v1.23, the following program prints 1 0, but it should print 1 1 by the rules specified in Go specification.

The bug has been fixed since Go toolchain v1.23.

package main

var x = 0
var a = foo()
var b = x

func foo() int {
	x++
	return x
}

func main() {
	println(a, b)
}

Case 2

Due to a compiler optimization bug, with Go toolchain versions prior to v1.22, the following program prints true, but it should print false by the rules specified in Go specification.

The bug has been fixed since Go toolchain v1.22.

package main

var _ = func() int {
	a = false
	return 0
}()

var a = true
var b = a

func main() {
	println(b)
}

Case 3

Due to a compiler bug, with Go toolchain versions prior to v1.12, the following program prints 5 4, but it should print 4 5 by the rules specified in Go specification.

The bug has been fixed since Go toolchain v1.13.

package main

var (
  a = c
  b = f()
  c = f()
  d = 3
)

func f() int {
  d++
  return d
}

func main() {
	println(b, c)
}

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