Some( NULL ) returns None

[kaseyc]

If you try to take Some of a null pointer, it will be interpreted as None. This seems to occur for any two element enum with the same signature as option,

Example:

enum Foo<T> {
    Bar(T),
    Baz
}

impl<T> Foo<T> {
    fn as_string(&self) -> String {
        match *self {
            Bar(_) => "Bar(_)".to_string(),
            Baz => "Baz".to_string(),
        }
    }

    fn is_bar(&self) -> bool {
        match *self {
            Bar(_) => true,
            _ => false
        }
    }

    fn is_baz(&self) -> bool {
        match *self {
            Baz => true,
            _ => false
        }
    }
}


fn main() {
        println!("Should be Some: {}", Some( 0u8 as *const u8))
        let foo = Bar( 0u8 as *const u8 );
        println!("Should be Bar: {}\nBar: {}, Baz: {}", foo.as_string(), foo.is_bar(), foo.is_baz() );
}

Which prints:

Should be Some: None
Should be Bar: Baz
Bar: false, Baz: true

[keeperofdakeys]

I'm guessing this is a nullable pointer bug. Can this be enabled only for borrows, and not for raw pointers?

[bluss]

I'd suspect this is from 52d6d3b @nick29581

[brson]

Nominating because I want to make sure this is solvable.

[pcwalton]

This is not a 1.0 issue, IMO. Just a miscompilation.

[pnkfelix]

Marking as P-backcompat-lang + 1.0 blocker, mostly because that is the conservative thing for us to do here at the moment. Hopefully we can fix quickly.