What are the problems that are mitigated by not allowing nested function declarations in Go?

Lambdas work as expected:

func main() {
    inc := func(x int) int { return x+1; }
}

However, the following declaration inside a declaration is not allowed:

func main() {
    func inc(x int) int { return x+1; }
}

For what reason are nested functions not allowed?

I think there are 3 reasons why this obvious feature isn't allowed

• It would complicate the compiler slightly. At the moment the compiler knows all functions are at the top level.

• It would make a new class of programmer error - you could refactor something and accidentally nest some functions.

• Having a different syntax for functions and closures is a good thing. Making a closure is potentially more expensive than making a function so you should know you are doing it.

Those are just my opinions though - I haven't seen an official pronouncement from the language designers.

Stack Overflow Q#21961615, score: 79