String concatenation doesn't seem to work?

[sinzin91]

[1] go-pry> x := "hello"
=> "hello"
[2] go-pry> x += " world"
=> " world"
[3] go-pry> x
=> " world"

The same thing in gore (https://github.com/motemen/gore)

gore> x := "hello"
"hello"
gore> x += " world"
"hello world"

[d4l3k]

Yup, surprised I hadn't caught that by now.