Summary

Fixed #6939. This bug was introduced in #6901 hastily merged without review.

In the implementation proposed below, biome uses a simple inference algorithm. We iterate over all ancestors of this expr and apply the following checks:

1. If a node is a function (only sync/async function declaration/expression, not methods) and is not used as a class/object member, we assign unknown.
2. If a node is a class decl/expr, we bind this to it.
3. If a node is an object and we have already encountered a function or an object method/getter/setter, we bind this to object.

If no node matched any of those steps, we also assign unknown.

Test Plan

Added several snapshot tests relying on basic inference to prove that type of this is deduced correctly.

Docs

Bugfix, N/A