Addition assignment operator (+=) broken

[ChristopheCorbalan]

Describe the bug

It seems like svelte@5.0.0-next.163 introduced the bug.

Whenever I create a state object and that I want to increment a number with the addition assignment operator it gets replaced by "++".

Input:

Output:

Reproduction

REPL

Logs

No response

System Info

System:
    OS: macOS 14.4
    CPU: (12) arm64 Apple M2 Max
    Memory: 8.76 GB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.6.1 - ~/.nvm/versions/node/v20.6.1/bin/node
    npm: 10.1.0 - ~/.nvm/versions/node/v20.6.1/bin/npm
    bun: 1.1.13 - ~/.bun/bin/bun
  Browsers:
    Chrome: 126.0.6478.114
    Firefox Nightly: 128.0a1
    Safari: 17.4

Severity

blocking an upgrade