Invalid behaviour with pointers

[zapateo]

Source code

package main

import "fmt"

var P = new(int)

func main() {
        fmt.Println(*P)
        *P = 32
        fmt.Println(*P)
        *P++
        fmt.Println(*P)
}

Scriggo output

0
32
4

gc output

0
32
33

Details

Note that this issue has been opened after closing #916.

[zapateo]

A simpler version of this issue:

package main

func main() {
	p := new(int)
	*p = 1
	*p += 5
	println(*p)
}

[zapateo]

Note that this code:

package main

func main() {
	p := new(int)
	*p = 1
	_ = *p
	*p += 5
	println(*p)
}

works as expected. The only difference with the previous one is the addition of _ = *p.