@s[type=...] is treated as @e[type=...]

The bug

When using type in an @s selector, it suddenly starts selecting all entities that meet the conditions rather than just the sender.

How to reproduce

1. Enter a world with any entities

2. /say @s

3. /say @s[type=!player]
   → ❌  Every entity in the world is found

Notes

Does not affect any other selector options