Libcst

Fixed

- Fix pyre command for type inference provider [523](https://github.com/Instagram/LibCST/pull/523)

Updated

- Change codegen to treat typing.Union[Foo, NoneType] and typing.Optional[Foo] as the same [508]((https://github.com/Instagram/LibCST/pull/508)
- Rewrite the MatchIfTrue type to be generic on \_MatchIfTrueT [512](https://github.com/Instagram/LibCST/pull/512)
- Add python3.9 to the CI [506](https://github.com/Instagram/LibCST/pull/506)
- Various CI changes [471](https://github.com/Instagram/LibCST/pull/471) [#510](https://github.com/Instagram/LibCST/pull/510) [#505](https://github.com/Instagram/LibCST/pull/505) [#515](https://github.com/Instagram/LibCST/pull/515) [#516](https://github.com/Instagram/LibCST/pull/516)

Fixed

- Don't reset subprocess environment to fix codemodding on windows [495](https://github.com/Instagram/LibCST/pull/495)
- TypeAnnotationsVisitor: don't truncate function return type [499](https://github.com/Instagram/LibCST/pull/499)
- Docs: Fix typo [492](https://github.com/Instagram/LibCST/pull/492)

Updated

- Return more specific QNames for assignments [477](https://github.com/Instagram/LibCST/pull/477)
- Tie accesses from string annotation to the string node [483](https://github.com/Instagram/LibCST/pull/483)

Fixed

- Fix leaking processes from TypeInferenceProvider [474](https://github.com/Instagram/LibCST/pull/474)
- Fix TypeInferenceProvider breakage with empty cache [476](https://github.com/Instagram/LibCST/pull/476)
- Fix formatting for link to QualifiedName class in docs [480](https://github.com/Instagram/LibCST/pull/480)

Added

- Add FlattenSentinel to support replacing a statement with multiple statements [455](https://github.com/Instagram/LibCST/pull/455)
- Add BuiltinScope [469](https://github.com/Instagram/LibCST/pull/469)
- Add FullyQualifiedNameProvider [465](https://github.com/Instagram/LibCST/pull/465)

Updated

- Split QualifiedNameProvider out from libcst.metadata.scope_provider [464](https://github.com/Instagram/LibCST/pull/464)

Fixed

- Exception while parsing escape character in raw f-strings [462](https://github.com/Instagram/LibCST/issues/462)

Updated

- Optimization: reduce the number of unused parallel processes [440](https://github.com/Instagram/LibCST/pull/440)

Fixed

- Walrus operator's left hand side now has STORE expression context [443](https://github.com/Instagram/LibCST/pull/433)
- ApplyTypeAnnotationsVisitor applies parameter annotations even if no return type is declared [445](https://github.com/Instagram/LibCST/pull/445)
- Work around Windows problem by using dummy pool for `jobs=1` [436](https://github.com/Instagram/LibCST/pull/436)
- Remove extra unused imports added in other files [453](https://github.com/Instagram/LibCST/pull/453)

Added

- Support PEP-604 style unions in decorator annotations [429](https://github.com/Instagram/LibCST/pull/429)
- Gathering exports in augmented assignment statements [426](https://github.com/Instagram/LibCST/pull/426)

Fixed

- Don't allow out of order accesses in the global scope [431](https://github.com/Instagram/LibCST/pull/431)
- Handle scope ordering in For statements [430](https://github.com/Instagram/LibCST/pull/430)
- Fix for not parsing subscripts such as `cast()["from"]` [428](https://github.com/Instagram/LibCST/pull/428)
- Walrus operator's left hand side now has STORE expression context [433](https://github.com/Instagram/LibCST/pull/433)