## Summary
The motivation of `ScopedExpressionId` was that we have an expression
identifier that's local to a scope and, therefore, unlikely to change if
a user makes changes in another scope. A local identifier like this has
the advantage that query results may remain unchanged even if other
parts of the file change, which in turn allows Salsa to short-circuit
dependent queries.
However, I noticed that we aren't using `ScopedExpressionId` in a place
where it's important that the identifier is local. It's main use is
inside `infer` which we always run for the entire file. The one
exception to this is `Unpack` but unpack runs as part of `infer`.
Edit: The above isn't entirely correct. We used ScopedExpressionId in
TypeInference which is a query result. Now using ExpressionNodeKey does
mean that a change to the AST invalidates most if not all TypeInference
results of a single file. Salsa then has to run all dependent queries to
see if they're affected by this change even if the change was local to
another scope.
If this locality proves to be important I suggest that we create two
queries on top of TypeInference: one that returns the expression map
which is mainly used in the linter and type inference and a second that
returns all remaining fields. This should give us a similar optimization
at a much lower cost
I also considered remove `ScopedUseId` but I believe that one is still
useful because using `ExpressionNodeKey` for it instead would mean that
all `UseDefMap` change when a single AST node changes. Whether this is
important is something difficult to assess. I'm simply not familiar
enough with the `UseDefMap`. If the locality doesn't matter for the
`UseDefMap`, then a similar change could be made and `bindings_by_use`
could be changed to an `FxHashMap<UseId, Bindings>` where `UseId` is a
thin wrapper around `NodeKey`.
Closes https://github.com/astral-sh/ty/issues/721
## Summary
https://github.com/astral-sh/ty/issues/214 will require a couple
invasive changes that I would like to get merged even before garbage
collection is fully implemented (to avoid rebasing):
- `ParsedModule` can no longer be dereferenced directly. Instead you
need to load a `ParsedModuleRef` to access the AST, which requires a
reference to the salsa database (as it may require re-parsing the AST if
it was collected).
- `AstNodeRef` can only be dereferenced with the `node` method, which
takes a reference to the `ParsedModuleRef`. This allows us to encode the
fact that ASTs do not live as long as the database and may be collected
as soon a given instance of a `ParsedModuleRef` is dropped. There are a
number of places where we currently merge the `'db` and `'ast`
lifetimes, so this requires giving some types/functions two separate
lifetime parameters.
## Summary
This PR partially solves https://github.com/astral-sh/ty/issues/164
(derived from #17643).
Currently, the definitions we manage are limited to those for simple
name (symbol) targets, but we expand this to track definitions for
attribute and subscript targets as well.
This was originally planned as part of the work in #17643, but the
changes are significant, so I made it a separate PR.
After merging this PR, I will reflect this changes in #17643.
There is still some incomplete work remaining, but the basic features
have been implemented, so I am publishing it as a draft PR.
Here is the TODO list (there may be more to come):
* [x] Complete rewrite and refactoring of documentation (removing
`Symbol` and replacing it with `Place`)
* [x] More thorough testing
* [x] Consolidation of duplicated code (maybe we can consolidate the
handling related to name, attribute, and subscript)
This PR replaces the current `Symbol` API with the `Place` API, which is
a concept that includes attributes and subscripts (the term is borrowed
from Rust).
## Test Plan
`mdtest/narrow/assignment.md` is added.
---------
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
