use any usage as inference information

```py
def f():
a = [1] # inferred as list[object] because of it's usage later
b: list[object] = a
```
- super issue of #519

Start with the example in the issue and read the related issue #519 to understand the intended inference behavior. Identify where basedmypy gathers type-inference information for later usage, then verify that the example's assignment produces the expected inferred type and add coverage for the demonstrated case.

Written by the indexing model from the issue text.