Match operand expected permissions doesn't match branches

[willcrichton]

This program:

fn main() {
let opt: Option<String> = 
    Some(String::from("Hello world"));

match opt {
    Some(_) => println!("Some!"),
    None => println!("None!")
};

println!("{:?}", opt);
}

Is visualized with these permission:

The match on opt should not require the own permission. Case in point, if you do let x = &opt and x is live across the match, the program still compiles.

[willcrichton]

Core issue is that match operand really only expects R for the discriminant operation. Any additional permission expectations should be placed on the patterns where things get bound.