[ty] Infer nonlocal types as unions of all reachable bindings#18750
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[ty] Infer nonlocal types as unions of all reachable bindings#18750
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## Summary As far as I can tell, the two existing tests did the exact same thing. Remove the redundant test, and add tests for all combinations of declared/not-declared and local/"public" use of the name. Proposing this as a separate PR before the behavior might change via #18750
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CodSpeed WallTime Performance ReportMerging #18750 will not alter performanceComparing Summary
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| builder.into_diagnostic(format_args!( | ||
| "Conflicting declared types for `{place}`: {}", | ||
| conflicting.display(db) | ||
| conflicting.iter().map(|ty| ty.display(db)).join(", ") |
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Can't easily get this to work with TypeArrayDisplay, so just join it manually.
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I added this function yesterday, which could possibly be generalised:
ruff/crates/ty_python_semantic/src/types/diagnostic.rs
Lines 2039 to 2064 in c1fed55
its behaviour is that if you have a list of two types A and B, it creates the string "`A` and `B`", if you have a list of three types A, B and C, it creates the string "`A`, `B` and `C`", for four types it creates the string "`A`, `B`, `C` and `D`", etc.
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I guess a generalised version would be something like this (untested):
fn describe_types_list<'db, I, IT, D>(db: &'db dyn Db, types: I) -> String
where
I: IntoIterator<IntoIter = IT>,
IT: ExactSizeIterator<Item = D> + DoubleEndedIterator,
D: std::fmt::Display,
{
let types = types.into_iter();
debug_assert!(types.len() >= 2);
let final_type = types.next_back().unwrap();
let penultimate_type = types.next_back().unwrap();
let mut buffer = String::new();
for type in types {
buffer.push('`');
buffer.push_str(type);
buffer.push_str("`, ");
}
buffer.push('`');
buffer.push_str(penultimate_type);
buffer.push_str("` and `");
buffer.push_str(final_type);
buffer.push('`');
buffer
}
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if you have a list of three types
A,BandC, it creates the string"`A`, `B` and `C`", for four types it creates the string"`A`, `B`, `C` and `D`", etc.
I see we are Oxford comma nemeses... 🐂
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Thank you, Alex. I'll keep this for a follow-up.
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* main: [ty] Add regression-benchmark for attribute-assignment hang (#18957) [ty] Format conflicting types as an enumeration (#18956) [ty] Prevent union builder construction for just one declaration (#18954) [ty] Infer nonlocal types as unions of all reachable bindings (#18750) [`pyflakes`] Mark `F504`/`F522`/`F523` autofix as unsafe if there's a call with side effect (#18839) [`playground`] Add ruff logo docs link to Header.tsx (#18947) [ty] Reduce the overwhelming complexity of `TypeInferenceBuilder::infer_call_expression` (#18943) [ty] Add subdiagnostic about empty bodies in more cases (#18942) [ty] Move search path resolution to `Options::to_program_settings` (#18937) [`flake8-errmsg`] Extend `EM101` to support byte strings (#18867) Move big rule implementations (#18931) [`pylint`] Allow fix with comments and document performance implications (`PLW3301`) (#18936)
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…lookups (#18955) ## 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 astral-sh/ty#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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Summary
This PR includes a behavioral change to how we infer types for nonlocal uses of symbols within a module. Where we would previously use the type that a use at the end of the scope would see, we now consider all reachable bindings and union the results:
This helps especially in cases where the the end of the scope is not reachable:
This PR also proposes to skip the boundness analysis of nonlocal uses. This is consistent with the "all reachable bindings" strategy, because the implicit
x = <unbound>binding is also always reachable, and we would have to emit "possibly-unresolved" diagnostics for every nonlocal use otherwise. Changing this behavior allows common use-cases like the following to type check without any errors:closes astral-sh/ty#210
closes astral-sh/ty#607
closes astral-sh/ty#699
Follow up
It is now possible to resolve the following TODO, but I would like to do that as a follow-up, because it requires some changes to how we treat implicit attribute assignments, which could result in ecosystem changes that I'd like to see separately.
ruff/crates/ty_python_semantic/src/semantic_index/builder.rs
Lines 1095 to 1117 in 315fb0f
Ecosystem analysis
Full report
possibly-unresolved-referencediagnostics (7818) because we do not analyze boundness for nonlocal uses of symbols inside modules anymore.unresolved-referencediagnostics (231) in scenarios like this:Test Plan
New Markdown tests