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Lazily evaluate all PEP 695 type alias values
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charliermarsh committed Oct 18, 2023
1 parent d685107 commit a33c0b7
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Showing 8 changed files with 79 additions and 16 deletions.
17 changes: 17 additions & 0 deletions crates/ruff_linter/resources/test/fixtures/pyflakes/F401_19.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
"""Test that type parameters are considered used."""

from __future__ import annotations

from typing import TYPE_CHECKING

if TYPE_CHECKING:
from collections.abc import Callable

from .foo import Record as Record1
from .bar import Record as Record2

type RecordCallback[R: Record1] = Callable[[R], None]


def process_record[R: Record2](record: R) -> None:
...
Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
"""Test lazy evaluation of type alias values."""

type RecordCallback[R: Record] = Callable[[R], None]

from collections.abc import Callable
4 changes: 2 additions & 2 deletions crates/ruff_linter/src/checkers/ast/deferred.rs
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use ruff_python_ast::{Expr, TypeParam};
use ruff_python_ast::{Expr};
use ruff_python_semantic::{ScopeId, Snapshot};
use ruff_text_size::TextRange;

Expand All @@ -10,7 +10,7 @@ pub(crate) struct Deferred<'a> {
pub(crate) scopes: Vec<ScopeId>,
pub(crate) string_type_definitions: Vec<(TextRange, &'a str, Snapshot)>,
pub(crate) future_type_definitions: Vec<(&'a Expr, Snapshot)>,
pub(crate) type_param_definitions: Vec<(&'a TypeParam, Snapshot)>,
pub(crate) type_param_definitions: Vec<(&'a Expr, Snapshot)>,
pub(crate) functions: Vec<Snapshot>,
pub(crate) lambdas: Vec<(&'a Expr, Snapshot)>,
pub(crate) for_loops: Vec<Snapshot>,
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34 changes: 22 additions & 12 deletions crates/ruff_linter/src/checkers/ast/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -582,9 +582,9 @@ where
if let Some(type_params) = type_params {
self.visit_type_params(type_params);
}
// The value in a `type` alias has annotation semantics, in that it's never
// evaluated at runtime.
self.visit_annotation(value);
self.deferred
.type_param_definitions
.push((value, self.semantic.snapshot()));
self.semantic.pop_scope();
self.visit_expr(name);
}
Expand Down Expand Up @@ -1389,9 +1389,14 @@ where
}
}
// Step 2: Traversal
self.deferred
.type_param_definitions
.push((type_param, self.semantic.snapshot()));
if let ast::TypeParam::TypeVar(ast::TypeParamTypeVar {
bound: Some(bound), ..
}) = type_param
{
self.deferred
.type_param_definitions
.push((bound, self.semantic.snapshot()));
}
}
}

Expand Down Expand Up @@ -1477,6 +1482,14 @@ impl<'a> Checker<'a> {
self.semantic.flags = snapshot;
}

/// Visit an [`Expr`], and treat it as a type parameter definition.
fn visit_type_param_definition(&mut self, expr: &'a Expr) {
let snapshot = self.semantic.flags;
self.semantic.flags |= SemanticModelFlags::TYPE_PARAM_DEFINITION;
self.visit_type_definition(expr);
self.semantic.flags = snapshot;
}

/// Visit an [`Expr`], and treat it as a type definition.
fn visit_type_definition(&mut self, expr: &'a Expr) {
let snapshot = self.semantic.flags;
Expand Down Expand Up @@ -1766,12 +1779,9 @@ impl<'a> Checker<'a> {
for (type_param, snapshot) in type_params {
self.semantic.restore(snapshot);

if let ast::TypeParam::TypeVar(ast::TypeParamTypeVar {
bound: Some(bound), ..
}) = type_param
{
self.visit_annotation(bound);
}
self.semantic.flags |=
SemanticModelFlags::TYPE_PARAM_DEFINITION | SemanticModelFlags::TYPE_DEFINITION;
self.visit_type_param_definition(type_param);
}
}
self.semantic.restore(snapshot);
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2 changes: 2 additions & 0 deletions crates/ruff_linter/src/rules/pyflakes/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,7 @@ mod tests {
#[test_case(Rule::UnusedImport, Path::new("F401_16.py"))]
#[test_case(Rule::UnusedImport, Path::new("F401_17.py"))]
#[test_case(Rule::UnusedImport, Path::new("F401_18.py"))]
#[test_case(Rule::UnusedImport, Path::new("F401_19.py"))]
#[test_case(Rule::ImportShadowedByLoopVar, Path::new("F402.py"))]
#[test_case(Rule::UndefinedLocalWithImportStar, Path::new("F403.py"))]
#[test_case(Rule::LateFutureImport, Path::new("F404.py"))]
Expand Down Expand Up @@ -135,6 +136,7 @@ mod tests {
#[test_case(Rule::UndefinedName, Path::new("F821_17.py"))]
#[test_case(Rule::UndefinedName, Path::new("F821_18.py"))]
#[test_case(Rule::UndefinedName, Path::new("F821_19.py"))]
#[test_case(Rule::UndefinedName, Path::new("F821_20.py"))]
#[test_case(Rule::UndefinedExport, Path::new("F822_0.py"))]
#[test_case(Rule::UndefinedExport, Path::new("F822_1.py"))]
#[test_case(Rule::UndefinedExport, Path::new("F822_2.py"))]
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
---
source: crates/ruff_linter/src/rules/pyflakes/mod.rs
---

Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
---
source: crates/ruff_linter/src/rules/pyflakes/mod.rs
---
F821_20.py:3:24: F821 Undefined name `Record`
|
1 | """Test lazy evaluation of type alias values."""
2 |
3 | type RecordCallback[R: Record] = Callable[[R], None]
| ^^^^^^ F821
4 |
5 | from collections.abc import Callable
|


15 changes: 13 additions & 2 deletions crates/ruff_python_semantic/src/model.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1600,6 +1600,16 @@ bitflags! {
/// ```
const FUTURE_ANNOTATIONS = 1 << 14;

/// The model is in a type parameter definition.
///
/// For example, the model could be visiting `Record` in:
/// ```python
/// from typing import TypeVar
///
/// Record = TypeVar("Record")
///
const TYPE_PARAM_DEFINITION = 1 << 15;

/// The context is in any type annotation.
const ANNOTATION = Self::TYPING_ONLY_ANNOTATION.bits() | Self::RUNTIME_ANNOTATION.bits();

Expand All @@ -1610,11 +1620,12 @@ bitflags! {
/// The context is in any deferred type definition.
const DEFERRED_TYPE_DEFINITION = Self::SIMPLE_STRING_TYPE_DEFINITION.bits()
| Self::COMPLEX_STRING_TYPE_DEFINITION.bits()
| Self::FUTURE_TYPE_DEFINITION.bits();
| Self::FUTURE_TYPE_DEFINITION.bits()
| Self::TYPE_PARAM_DEFINITION.bits();

/// The context is in a typing-only context.
const TYPING_CONTEXT = Self::TYPE_CHECKING_BLOCK.bits() | Self::TYPING_ONLY_ANNOTATION.bits() |
Self::STRING_TYPE_DEFINITION.bits();
Self::STRING_TYPE_DEFINITION.bits() | Self::TYPE_PARAM_DEFINITION.bits();
}
}

Expand Down

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