recover() does not behave as expected

[deelawn]

In go, calling recover() only works inside a defer to handle panics that originated within the current call frame. From the definition here:

If recover is called outside the deferred function it will not stop a panicking sequence

This is not the case in gno; calling recover() in gno will recover any panic that has happened inside or outside of the current call frame. Take this code example:

package main

func doSomething() {
	defer func() {
		doSomethingElse()
		if r := recover(); r != nil {
			panic("do something panic")
		}
	}()
	panic("")
}

func doSomethingElse() {
	if r := recover(); r != nil {
		panic("do something else panic")
	}
}

func main() {
	doSomething()
}

The output should be a panic with the message do something panic. Instead we get the message do something else panic.

I think perhaps the path to solving this is to save panics in the last call frame's struct rather than in the machine's struct.

Note that fixing this will render the testing standard library's Recover method useless.