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![]() ## Summary Remove a hack in control flow modeling that was treating `return` statements at the end of function bodies in a special way (basically considering the state *just before* the `return` statement as the end-of-scope state). This is not needed anymore now that #18750 has been merged. In order to make this work, we now use *all reachable bindings* for purposes of finding implicit instance attribute assignments as well as for deferred lookups of symbols. Both would otherwise be affected by this change: ```py def C: def f(self): self.x = 1 # a reachable binding that is not visible at the end of the scope return ``` ```py def f(): class X: ... # a reachable binding that is not visible at the end of the scope x: "X" = X() # deferred use of `X` return ``` Implicit instance attributes also required another change. We previously kept track of possibly-unbound instance attributes in some cases, but we now give up on that completely and always consider *implicit* instance attributes to be bound if we see a reachable binding in a reachable method. The previous behavior was somewhat inconsistent anyway because we also do not consider attributes possibly-unbound in other scenarios: we do not (and can not) keep track of whether or not methods are called that define these attributes. closes https://github.com/astral-sh/ty/issues/711 ## Ecosystem analysis I think this looks very positive! * We see an unsurprising drop in `possibly-unbound-attribute` diagnostics (599), mostly for classes that define attributes in `try … except` blocks, `for` loops, or `if … else: raise …` constructs. There might obviously also be true positives that got removed, but the vast majority should be false positives. * There is also a drop in `possibly-unresolved-reference` / `unresolved-reference` diagnostics (279+13) from the change to deferred lookups. * Some `invalid-type-form` false positives got resolved (13), because we can now properly look up the names in the annotations. * There are some new *true* positives in `attrs`, since we understand the `Attribute` annotation that was previously inferred as `Unknown` because of a re-assignment after the class definition. ## Test Plan The existing attributes.md test suite has sufficient coverage here. |
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annotations | ||
assignment | ||
binary | ||
boolean | ||
boundness_declaredness | ||
call | ||
class | ||
comparison | ||
comprehensions | ||
conditional | ||
declaration | ||
diagnostics | ||
directives | ||
doc | ||
exception | ||
expression | ||
function | ||
generics | ||
ide_support | ||
import | ||
literal | ||
loops | ||
narrow | ||
regression | ||
scopes | ||
shadowing | ||
snapshots | ||
stubs | ||
subscript | ||
suppressions | ||
type_compendium | ||
type_of | ||
type_properties | ||
type_qualifiers | ||
unary | ||
with | ||
.mdformat.toml | ||
attributes.md | ||
cycle.md | ||
dataclass_transform.md | ||
dataclasses.md | ||
decorators.md | ||
del.md | ||
descriptor_protocol.md | ||
final.md | ||
instance_layout_conflict.md | ||
intersection_types.md | ||
invalid_syntax.md | ||
known_constants.md | ||
mdtest_config.md | ||
mdtest_custom_typeshed.md | ||
metaclass.md | ||
mro.md | ||
named_tuple.md | ||
overloads.md | ||
pep695_type_aliases.md | ||
properties.md | ||
protocols.md | ||
public_types.md | ||
statically_known_branches.md | ||
sys_platform.md | ||
sys_version_info.md | ||
terminal_statements.md | ||
type_api.md | ||
typed_dict.md | ||
union_types.md | ||
unpacking.md | ||
unreachable.md |