Immutability by default

[giann]

Should things be immutable (and private) by default?

str hello = "hello";
hello = "bye"; | fails

var str hello = "hello";
hello = "bye"; | ok

[vexy]

Hard big YES. Not only that "others" are doing it for years now, but enforcing immutability on a compiler level brings a lot of safety out of the box.

It may eventually lead to questions of "borrowing & ownership" (arrived in Swift 5.9, present in Rust since v1) but that's another subject.

Imho, this should be by default.

[giann]

Enforcing immutability should be relatively straightforward. Implementing this should also pave the way to resolve/implement:

• Static property values don't need to be constant #155
• Enum instance should be usable as default values #145
• Immutable objects #114
• Remove dead branches #52
• #14
• Constant object/class properties #13