incrementing/decrement on const

[ElianHugh]

The following works as expected, and vapour flags it as an error

const x: int = 1
x = x + 1 # `x` is a constant

However, the following compiles fine (when it shouldn't)

const x: int = 1
x += 1

[JohnCoene]

Indeed, that's most definitely a bug, thank you for reporting it!