package main

import "fmt"

//
// Demonstrate a problem whereby a uint8 loop variable in a nested loop results in
// the loop variable an enclosing loop not being incremented.
//
// go version go1.2 linux/amd64
// ubuntu 12.04
//
// The program should terminate but it gets stuck in the second loop.
//
func main() {
	loop1()
	loop2()
}

const lim = int(1 << 7)
const inc = 64

// loop1 works:  ii increments as expected.
//
func loop1() {
	for ii := 0; ii < lim; ii += inc {
		for jj := 0; jj < lim; jj += inc {
			fmt.Printf("%d %d\n", ii, jj)
		}
	}
}

// loop2 doesn't work:
// on my desktop ii doesn't increment,
// on play.golang.org it results in the server error: "Error communicating with remote server."
//
// It's the uint8 that triggers the problem.
//
func loop2() {
	for ii := 0; ii < lim; ii += inc {
		for jj := int8(0); int(jj) < lim; jj += inc {
			fmt.Printf("%d %d\n", ii, jj)
		}
	}
}