Compiler says string is not it's own type

[RichardlL]

I have the code
let mut vari = "";
...
vari = vari + str::from_char(chr);

(I cant used an owned string, because i have a large pattern match, and it wont accept ~"String to match", as it interprets it as a a owned static string instead of a owned string, and it wont accept "String to match".to_owned() either)

But back to the problem, it says vari doesnt have an appropriate type for vari?

src/main.rs:161:11: 161:37 error: mismatched types: expected &'static str but found ~str (str storage differs: expected &'static but found ~)

src/main.rs:161             vari = vari + str::from_char(chr); 
                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to previous 

and i cant use += as that results in
binary assignment operation += cannot be applied to type &static str

Im not sure if this is a bug, but it's confusing me

[Ryman]

Rust won't allow manipulation of static strings, you'll want to use the StrBuf type. http://static.rust-lang.org/doc/master/std/strbuf/struct.StrBuf.html

You can match on vari.as_slice(), try the following:

let mut vari = StrBuf::new();
vari.push_char('c');

match vari.as_slice() {
    "c" => println!("Got a `c`"),
    _ => println!("Not a `c`")
}

[alexcrichton]

The error message is correct in that + returns ~str (in this case) instead of &'static str (the type of a string literal). @Ryman has some good suggestions about how you can continue to pattern match even with owned strings.

Closing as working as intended.