Nil pointer confusion

Question

I'm trying to wrap my head around this playground https://play.golang.org/p/CJmDivZGrZM

I don't understand why this if statement claims err != nil

if err := baz(); err == nil {
    fmt.Println("3. No error", err == nil)
} else {
    fmt.Println("3. Error, err != nil ", err, err == nil)
}

The output from that if/else is "3. Error, err != nil false", so print sees it's nil, but the comparison doesn't. If I try to access err.Error() is it panicking and crashing.

My two questions are:

• Why is the comparison not seeing err as nil?
• Why isn't it caught by the compiler?