mirror of https://github.com/astral-sh/ruff
1231 lines
44 KiB
Rust
1231 lines
44 KiB
Rust
//! [`SemanticSyntaxChecker`] for AST-based syntax errors.
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//!
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//! This checker is not responsible for traversing the AST itself. Instead, its
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//! [`SemanticSyntaxChecker::visit_stmt`] and [`SemanticSyntaxChecker::visit_expr`] methods should
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//! be called in a parent `Visitor`'s `visit_stmt` and `visit_expr` methods, respectively.
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use std::fmt::Display;
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use ruff_python_ast::{
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self as ast,
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comparable::ComparableExpr,
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visitor::{walk_expr, Visitor},
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Expr, ExprContext, IrrefutablePatternKind, Pattern, PythonVersion, Stmt, StmtExpr,
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StmtImportFrom,
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};
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use ruff_text_size::{Ranged, TextRange, TextSize};
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use rustc_hash::FxHashSet;
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#[derive(Debug)]
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pub struct SemanticSyntaxChecker {
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/// The checker has traversed past the `__future__` import boundary.
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///
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/// For example, the checker could be visiting `x` in:
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///
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/// ```python
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/// from __future__ import annotations
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///
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/// import os
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///
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/// x: int = 1
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/// ```
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///
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/// Python considers it a syntax error to import from `__future__` after any other
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/// non-`__future__`-importing statements.
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seen_futures_boundary: bool,
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}
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impl SemanticSyntaxChecker {
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pub fn new() -> Self {
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Self {
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seen_futures_boundary: false,
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}
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}
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}
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impl SemanticSyntaxChecker {
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fn add_error<Ctx: SemanticSyntaxContext>(
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context: &Ctx,
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kind: SemanticSyntaxErrorKind,
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range: TextRange,
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) {
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context.report_semantic_error(SemanticSyntaxError {
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kind,
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range,
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python_version: context.python_version(),
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});
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}
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fn check_stmt<Ctx: SemanticSyntaxContext>(&mut self, stmt: &ast::Stmt, ctx: &Ctx) {
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match stmt {
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Stmt::ImportFrom(StmtImportFrom { range, module, .. }) => {
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if self.seen_futures_boundary && matches!(module.as_deref(), Some("__future__")) {
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Self::add_error(ctx, SemanticSyntaxErrorKind::LateFutureImport, *range);
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}
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}
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Stmt::Match(match_stmt) => {
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Self::irrefutable_match_case(match_stmt, ctx);
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for case in &match_stmt.cases {
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let mut visitor = MatchPatternVisitor {
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names: FxHashSet::default(),
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ctx,
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};
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visitor.visit_pattern(&case.pattern);
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}
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}
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Stmt::FunctionDef(ast::StmtFunctionDef { type_params, .. })
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| Stmt::ClassDef(ast::StmtClassDef { type_params, .. })
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| Stmt::TypeAlias(ast::StmtTypeAlias { type_params, .. }) => {
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if let Some(type_params) = type_params {
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Self::duplicate_type_parameter_name(type_params, ctx);
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}
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}
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Stmt::Assign(ast::StmtAssign { targets, .. }) => {
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if let [Expr::Starred(ast::ExprStarred { range, .. })] = targets.as_slice() {
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// test_ok single_starred_assignment_target
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// (*a,) = (1,)
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// *a, = (1,)
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// [*a] = (1,)
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// test_err single_starred_assignment_target
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// *a = (1,)
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Self::add_error(
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ctx,
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SemanticSyntaxErrorKind::SingleStarredAssignment,
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*range,
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);
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}
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}
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Stmt::Return(ast::StmtReturn {
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value: Some(value), ..
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}) => {
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// test_err single_star_return
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// def f(): return *x
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Self::invalid_star_expression(value, ctx);
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}
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Stmt::For(ast::StmtFor { target, iter, .. }) => {
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// test_err single_star_for
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// for _ in *x: ...
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// for *x in xs: ...
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Self::invalid_star_expression(target, ctx);
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Self::invalid_star_expression(iter, ctx);
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}
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_ => {}
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}
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Self::debug_shadowing(stmt, ctx);
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Self::check_annotation(stmt, ctx);
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}
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fn check_annotation<Ctx: SemanticSyntaxContext>(stmt: &ast::Stmt, ctx: &Ctx) {
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match stmt {
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Stmt::FunctionDef(ast::StmtFunctionDef {
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type_params,
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parameters,
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returns,
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..
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}) => {
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// test_ok valid_annotation_function
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// def f() -> (y := 3): ...
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// def g(arg: (x := 1)): ...
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// test_err invalid_annotation_function
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// def f[T]() -> (y := 3): ...
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// def g[T](arg: (x := 1)): ...
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// def h[T](x: (yield 1)): ...
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// def i(x: (yield 1)): ...
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// def j[T]() -> (yield 1): ...
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// def k() -> (yield 1): ...
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// def l[T](x: (yield from 1)): ...
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// def m(x: (yield from 1)): ...
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// def n[T]() -> (yield from 1): ...
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// def o() -> (yield from 1): ...
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// def p[T: (yield 1)](): ... # yield in TypeVar bound
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// def q[T = (yield 1)](): ... # yield in TypeVar default
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// def r[*Ts = (yield 1)](): ... # yield in TypeVarTuple default
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// def s[**Ts = (yield 1)](): ... # yield in ParamSpec default
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// def t[T: (x := 1)](): ... # named expr in TypeVar bound
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// def u[T = (x := 1)](): ... # named expr in TypeVar default
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// def v[*Ts = (x := 1)](): ... # named expr in TypeVarTuple default
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// def w[**Ts = (x := 1)](): ... # named expr in ParamSpec default
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let is_generic = type_params.is_some();
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let mut visitor = InvalidExpressionVisitor {
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allow_named_expr: !is_generic,
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position: InvalidExpressionPosition::TypeAnnotation,
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ctx,
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};
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if let Some(type_params) = type_params {
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visitor.visit_type_params(type_params);
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}
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if is_generic {
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visitor.position = InvalidExpressionPosition::GenericDefinition;
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} else {
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visitor.position = InvalidExpressionPosition::TypeAnnotation;
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}
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for param in parameters
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.iter()
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.filter_map(ast::AnyParameterRef::annotation)
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{
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visitor.visit_expr(param);
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}
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if let Some(returns) = returns {
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visitor.visit_expr(returns);
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}
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}
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Stmt::ClassDef(ast::StmtClassDef {
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type_params,
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arguments,
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..
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}) => {
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// test_ok valid_annotation_class
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// class F(y := list): ...
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// test_err invalid_annotation_class
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// class F[T](y := list): ...
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// class G((yield 1)): ...
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// class H((yield from 1)): ...
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// class I[T]((yield 1)): ...
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// class J[T]((yield from 1)): ...
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// class K[T: (yield 1)]: ... # yield in TypeVar
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// class L[T: (x := 1)]: ... # named expr in TypeVar
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let is_generic = type_params.is_some();
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let mut visitor = InvalidExpressionVisitor {
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allow_named_expr: !is_generic,
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position: InvalidExpressionPosition::TypeAnnotation,
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ctx,
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};
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if let Some(type_params) = type_params {
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visitor.visit_type_params(type_params);
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}
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if is_generic {
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visitor.position = InvalidExpressionPosition::GenericDefinition;
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} else {
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visitor.position = InvalidExpressionPosition::BaseClass;
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}
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if let Some(arguments) = arguments {
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visitor.visit_arguments(arguments);
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}
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}
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Stmt::TypeAlias(ast::StmtTypeAlias {
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type_params, value, ..
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}) => {
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// test_err invalid_annotation_type_alias
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// type X[T: (yield 1)] = int # TypeVar bound
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// type X[T = (yield 1)] = int # TypeVar default
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// type X[*Ts = (yield 1)] = int # TypeVarTuple default
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// type X[**Ts = (yield 1)] = int # ParamSpec default
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// type Y = (yield 1) # yield in value
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// type Y = (x := 1) # named expr in value
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let mut visitor = InvalidExpressionVisitor {
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allow_named_expr: false,
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position: InvalidExpressionPosition::TypeAlias,
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ctx,
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};
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visitor.visit_expr(value);
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if let Some(type_params) = type_params {
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visitor.visit_type_params(type_params);
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}
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}
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_ => {}
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}
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}
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/// Emit a [`SemanticSyntaxErrorKind::InvalidStarExpression`] if `expr` is starred.
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fn invalid_star_expression<Ctx: SemanticSyntaxContext>(expr: &Expr, ctx: &Ctx) {
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// test_ok single_star_in_tuple
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// def f(): yield (*x,)
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// def f(): return (*x,)
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// for _ in (*x,): ...
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// for (*x,) in xs: ...
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if expr.is_starred_expr() {
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Self::add_error(
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ctx,
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SemanticSyntaxErrorKind::InvalidStarExpression,
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expr.range(),
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);
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}
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}
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/// Check for [`SemanticSyntaxErrorKind::WriteToDebug`] in `stmt`.
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fn debug_shadowing<Ctx: SemanticSyntaxContext>(stmt: &ast::Stmt, ctx: &Ctx) {
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match stmt {
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Stmt::FunctionDef(ast::StmtFunctionDef {
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name,
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type_params,
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parameters,
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..
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}) => {
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// test_err debug_shadow_function
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// def __debug__(): ... # function name
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// def f[__debug__](): ... # type parameter name
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// def f(__debug__): ... # parameter name
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Self::check_identifier(name, ctx);
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if let Some(type_params) = type_params {
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for type_param in type_params.iter() {
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Self::check_identifier(type_param.name(), ctx);
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}
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}
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for parameter in parameters {
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Self::check_identifier(parameter.name(), ctx);
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}
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}
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Stmt::ClassDef(ast::StmtClassDef {
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name, type_params, ..
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}) => {
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// test_err debug_shadow_class
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// class __debug__: ... # class name
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// class C[__debug__]: ... # type parameter name
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Self::check_identifier(name, ctx);
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if let Some(type_params) = type_params {
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for type_param in type_params.iter() {
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Self::check_identifier(type_param.name(), ctx);
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}
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}
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}
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Stmt::TypeAlias(ast::StmtTypeAlias {
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type_params: Some(type_params),
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..
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}) => {
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// test_err debug_shadow_type_alias
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// type __debug__ = list[int] # visited as an Expr but still flagged
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// type Debug[__debug__] = str
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for type_param in type_params.iter() {
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Self::check_identifier(type_param.name(), ctx);
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}
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}
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Stmt::Import(ast::StmtImport { names, .. })
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| Stmt::ImportFrom(ast::StmtImportFrom { names, .. }) => {
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// test_err debug_shadow_import
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// import __debug__
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// import debug as __debug__
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// from x import __debug__
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// from x import debug as __debug__
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// test_ok debug_rename_import
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// import __debug__ as debug
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// from __debug__ import Some
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// from x import __debug__ as debug
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for name in names {
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match &name.asname {
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Some(asname) => Self::check_identifier(asname, ctx),
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None => Self::check_identifier(&name.name, ctx),
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}
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}
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}
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Stmt::Try(ast::StmtTry { handlers, .. }) => {
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// test_err debug_shadow_try
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// try: ...
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// except Exception as __debug__: ...
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for handler in handlers
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.iter()
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.filter_map(ast::ExceptHandler::as_except_handler)
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{
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if let Some(name) = &handler.name {
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Self::check_identifier(name, ctx);
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}
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}
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}
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// test_err debug_shadow_with
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// with open("foo.txt") as __debug__: ...
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_ => {}
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}
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}
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/// Check if `ident` is equal to `__debug__` and emit a
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/// [`SemanticSyntaxErrorKind::WriteToDebug`] if so.
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fn check_identifier<Ctx: SemanticSyntaxContext>(ident: &ast::Identifier, ctx: &Ctx) {
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if ident.id == "__debug__" {
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Self::add_error(
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ctx,
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SemanticSyntaxErrorKind::WriteToDebug(WriteToDebugKind::Store),
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ident.range,
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);
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}
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}
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fn duplicate_type_parameter_name<Ctx: SemanticSyntaxContext>(
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type_params: &ast::TypeParams,
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ctx: &Ctx,
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) {
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if type_params.len() < 2 {
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return;
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}
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for (i, type_param) in type_params.iter().enumerate() {
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if type_params
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.iter()
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.take(i)
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.any(|t| t.name().id == type_param.name().id)
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{
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// test_ok non_duplicate_type_parameter_names
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// type Alias[T] = list[T]
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// def f[T](t: T): ...
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// class C[T]: ...
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// class C[T, U, V]: ...
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// type Alias[T, U: str, V: (str, bytes), *Ts, **P, D = default] = ...
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// test_err duplicate_type_parameter_names
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// type Alias[T, T] = ...
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// def f[T, T](t: T): ...
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// class C[T, T]: ...
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// type Alias[T, U: str, V: (str, bytes), *Ts, **P, T = default] = ...
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// def f[T, T, T](): ... # two errors
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// def f[T, *T](): ... # star is still duplicate
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// def f[T, **T](): ... # as is double star
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Self::add_error(
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ctx,
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SemanticSyntaxErrorKind::DuplicateTypeParameter,
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type_param.range(),
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);
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}
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}
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}
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fn irrefutable_match_case<Ctx: SemanticSyntaxContext>(stmt: &ast::StmtMatch, ctx: &Ctx) {
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// test_ok irrefutable_case_pattern_at_end
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// match x:
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// case 2: ...
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// case var: ...
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// match x:
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// case 2: ...
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// case _: ...
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// match x:
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// case var if True: ... # don't try to refute a guarded pattern
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// case 2: ...
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|
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// test_err irrefutable_case_pattern
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// match x:
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// case var: ... # capture pattern
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// case 2: ...
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// match x:
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// case _: ...
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// case 2: ... # wildcard pattern
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// match x:
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// case var1 as var2: ... # as pattern with irrefutable left-hand side
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// case 2: ...
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// match x:
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// case enum.variant | var: ... # or pattern with irrefutable part
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// case 2: ...
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for case in stmt
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.cases
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.iter()
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.rev()
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.skip(1)
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.filter_map(|case| match case.guard {
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Some(_) => None,
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None => case.pattern.irrefutable_pattern(),
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})
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{
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Self::add_error(
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ctx,
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SemanticSyntaxErrorKind::IrrefutableCasePattern(case.kind),
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case.range,
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);
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}
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}
|
|
|
|
pub fn visit_stmt<Ctx: SemanticSyntaxContext>(&mut self, stmt: &ast::Stmt, ctx: &Ctx) {
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// update internal state
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match stmt {
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Stmt::Expr(StmtExpr { value, .. })
|
|
if !ctx.seen_docstring_boundary() && value.is_string_literal_expr() => {}
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|
Stmt::ImportFrom(StmtImportFrom { module, .. }) => {
|
|
// Allow __future__ imports until we see a non-__future__ import.
|
|
if !matches!(module.as_deref(), Some("__future__")) {
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self.seen_futures_boundary = true;
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|
}
|
|
}
|
|
_ => {
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|
self.seen_futures_boundary = true;
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}
|
|
}
|
|
|
|
// check for errors
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self.check_stmt(stmt, ctx);
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|
}
|
|
|
|
pub fn visit_expr<Ctx: SemanticSyntaxContext>(&mut self, expr: &Expr, ctx: &Ctx) {
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match expr {
|
|
Expr::ListComp(ast::ExprListComp {
|
|
elt, generators, ..
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|
})
|
|
| Expr::SetComp(ast::ExprSetComp {
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|
elt, generators, ..
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})
|
|
| Expr::Generator(ast::ExprGenerator {
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|
elt, generators, ..
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|
}) => Self::check_generator_expr(elt, generators, ctx),
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|
Expr::DictComp(ast::ExprDictComp {
|
|
key,
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value,
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|
generators,
|
|
..
|
|
}) => {
|
|
Self::check_generator_expr(key, generators, ctx);
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Self::check_generator_expr(value, generators, ctx);
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|
}
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|
Expr::Name(ast::ExprName {
|
|
range,
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|
id,
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|
ctx: expr_ctx,
|
|
}) => {
|
|
// test_err write_to_debug_expr
|
|
// del __debug__
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|
// del x, y, __debug__, z
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|
// __debug__ = 1
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// x, y, __debug__, z = 1, 2, 3, 4
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|
|
// test_err del_debug_py39
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|
// # parse_options: {"target-version": "3.9"}
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|
// del __debug__
|
|
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|
// test_ok del_debug_py38
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// # parse_options: {"target-version": "3.8"}
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// del __debug__
|
|
|
|
// test_ok read_from_debug
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|
// if __debug__: ...
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|
// x = __debug__
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|
if id == "__debug__" {
|
|
match expr_ctx {
|
|
ExprContext::Store => Self::add_error(
|
|
ctx,
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|
SemanticSyntaxErrorKind::WriteToDebug(WriteToDebugKind::Store),
|
|
*range,
|
|
),
|
|
ExprContext::Del => {
|
|
let version = ctx.python_version();
|
|
if version >= PythonVersion::PY39 {
|
|
Self::add_error(
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|
ctx,
|
|
SemanticSyntaxErrorKind::WriteToDebug(
|
|
WriteToDebugKind::Delete(version),
|
|
),
|
|
*range,
|
|
);
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
// PLE0118
|
|
if let Some(stmt) = ctx.global(id) {
|
|
let start = stmt.start();
|
|
if expr.start() < start {
|
|
Self::add_error(
|
|
ctx,
|
|
SemanticSyntaxErrorKind::LoadBeforeGlobalDeclaration {
|
|
name: id.to_string(),
|
|
start,
|
|
},
|
|
expr.range(),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
Expr::Yield(ast::ExprYield {
|
|
value: Some(value), ..
|
|
}) => {
|
|
// test_err single_star_yield
|
|
// def f(): yield *x
|
|
Self::invalid_star_expression(value, ctx);
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
/// Add a [`SyntaxErrorKind::ReboundComprehensionVariable`] if `expr` rebinds an iteration
|
|
/// variable in `generators`.
|
|
fn check_generator_expr<Ctx: SemanticSyntaxContext>(
|
|
expr: &Expr,
|
|
comprehensions: &[ast::Comprehension],
|
|
ctx: &Ctx,
|
|
) {
|
|
let rebound_variables = {
|
|
let mut visitor = ReboundComprehensionVisitor {
|
|
comprehensions,
|
|
rebound_variables: Vec::new(),
|
|
};
|
|
visitor.visit_expr(expr);
|
|
visitor.rebound_variables
|
|
};
|
|
|
|
// TODO(brent) with multiple diagnostic ranges, we could mark both the named expr (current)
|
|
// and the name expr being rebound
|
|
for range in rebound_variables {
|
|
// test_err rebound_comprehension_variable
|
|
// [(a := 0) for a in range(0)]
|
|
// {(a := 0) for a in range(0)}
|
|
// {(a := 0): val for a in range(0)}
|
|
// {key: (a := 0) for a in range(0)}
|
|
// ((a := 0) for a in range(0))
|
|
// [[(a := 0)] for a in range(0)]
|
|
// [(a := 0) for b in range (0) for a in range(0)]
|
|
// [(a := 0) for a in range (0) for b in range(0)]
|
|
// [((a := 0), (b := 1)) for a in range (0) for b in range(0)]
|
|
|
|
// test_ok non_rebound_comprehension_variable
|
|
// [a := 0 for x in range(0)]
|
|
Self::add_error(
|
|
ctx,
|
|
SemanticSyntaxErrorKind::ReboundComprehensionVariable,
|
|
range,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Default for SemanticSyntaxChecker {
|
|
fn default() -> Self {
|
|
Self::new()
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
|
|
pub struct SemanticSyntaxError {
|
|
pub kind: SemanticSyntaxErrorKind,
|
|
pub range: TextRange,
|
|
pub python_version: PythonVersion,
|
|
}
|
|
|
|
impl Display for SemanticSyntaxError {
|
|
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
|
match &self.kind {
|
|
SemanticSyntaxErrorKind::LateFutureImport => {
|
|
f.write_str("__future__ imports must be at the top of the file")
|
|
}
|
|
SemanticSyntaxErrorKind::ReboundComprehensionVariable => {
|
|
f.write_str("assignment expression cannot rebind comprehension variable")
|
|
}
|
|
SemanticSyntaxErrorKind::DuplicateTypeParameter => {
|
|
f.write_str("duplicate type parameter")
|
|
}
|
|
SemanticSyntaxErrorKind::MultipleCaseAssignment(name) => {
|
|
write!(f, "multiple assignments to name `{name}` in pattern")
|
|
}
|
|
SemanticSyntaxErrorKind::IrrefutableCasePattern(kind) => match kind {
|
|
// These error messages are taken from CPython's syntax errors
|
|
IrrefutablePatternKind::Name(name) => {
|
|
write!(
|
|
f,
|
|
"name capture `{name}` makes remaining patterns unreachable"
|
|
)
|
|
}
|
|
IrrefutablePatternKind::Wildcard => {
|
|
f.write_str("wildcard makes remaining patterns unreachable")
|
|
}
|
|
},
|
|
SemanticSyntaxErrorKind::SingleStarredAssignment => {
|
|
f.write_str("starred assignment target must be in a list or tuple")
|
|
}
|
|
SemanticSyntaxErrorKind::WriteToDebug(kind) => match kind {
|
|
WriteToDebugKind::Store => f.write_str("cannot assign to `__debug__`"),
|
|
WriteToDebugKind::Delete(python_version) => {
|
|
write!(f, "cannot delete `__debug__` on Python {python_version} (syntax was removed in 3.9)")
|
|
}
|
|
},
|
|
SemanticSyntaxErrorKind::InvalidExpression(
|
|
kind,
|
|
InvalidExpressionPosition::BaseClass,
|
|
) => {
|
|
write!(f, "{kind} cannot be used as a base class")
|
|
}
|
|
SemanticSyntaxErrorKind::InvalidExpression(kind, position) => {
|
|
write!(f, "{kind} cannot be used within a {position}")
|
|
}
|
|
SemanticSyntaxErrorKind::DuplicateMatchKey(key) => {
|
|
write!(
|
|
f,
|
|
"mapping pattern checks duplicate key `{}`",
|
|
EscapeDefault(key)
|
|
)
|
|
}
|
|
SemanticSyntaxErrorKind::DuplicateMatchClassAttribute(name) => {
|
|
write!(f, "attribute name `{name}` repeated in class pattern",)
|
|
}
|
|
SemanticSyntaxErrorKind::LoadBeforeGlobalDeclaration { name, start: _ } => {
|
|
write!(f, "name `{name}` is used prior to global declaration")
|
|
}
|
|
SemanticSyntaxErrorKind::InvalidStarExpression => {
|
|
f.write_str("can't use starred expression here")
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
|
|
pub enum SemanticSyntaxErrorKind {
|
|
/// Represents the use of a `__future__` import after the beginning of a file.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// from pathlib import Path
|
|
///
|
|
/// from __future__ import annotations
|
|
/// ```
|
|
///
|
|
/// This corresponds to the [`late-future-import`] (`F404`) rule in ruff.
|
|
///
|
|
/// [`late-future-import`]: https://docs.astral.sh/ruff/rules/late-future-import/
|
|
LateFutureImport,
|
|
|
|
/// Represents the rebinding of the iteration variable of a list, set, or dict comprehension or
|
|
/// a generator expression.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// [(a := 0) for a in range(0)]
|
|
/// {(a := 0) for a in range(0)}
|
|
/// {(a := 0): val for a in range(0)}
|
|
/// {key: (a := 0) for a in range(0)}
|
|
/// ((a := 0) for a in range(0))
|
|
/// ```
|
|
ReboundComprehensionVariable,
|
|
|
|
/// Represents a duplicate type parameter name in a function definition, class definition, or
|
|
/// type alias statement.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// type Alias[T, T] = ...
|
|
/// def f[T, T](t: T): ...
|
|
/// class C[T, T]: ...
|
|
/// ```
|
|
DuplicateTypeParameter,
|
|
|
|
/// Represents a duplicate binding in a `case` pattern of a `match` statement.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// match x:
|
|
/// case [x, y, x]: ...
|
|
/// case x as x: ...
|
|
/// case Class(x=1, x=2): ...
|
|
/// ```
|
|
MultipleCaseAssignment(ast::name::Name),
|
|
|
|
/// Represents an irrefutable `case` pattern before the last `case` in a `match` statement.
|
|
///
|
|
/// According to the [Python reference], "a match statement may have at most one irrefutable
|
|
/// case block, and it must be last."
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// match x:
|
|
/// case value: ... # irrefutable capture pattern
|
|
/// case other: ...
|
|
///
|
|
/// match x:
|
|
/// case _: ... # irrefutable wildcard pattern
|
|
/// case other: ...
|
|
/// ```
|
|
///
|
|
/// [Python reference]: https://docs.python.org/3/reference/compound_stmts.html#irrefutable-case-blocks
|
|
IrrefutableCasePattern(IrrefutablePatternKind),
|
|
|
|
/// Represents a single starred assignment target outside of a tuple or list.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// *a = (1,) # SyntaxError
|
|
/// ```
|
|
///
|
|
/// A starred assignment target can only occur within a tuple or list:
|
|
///
|
|
/// ```python
|
|
/// b, *a = 1, 2, 3
|
|
/// (*a,) = 1, 2, 3
|
|
/// [*a] = 1, 2, 3
|
|
/// ```
|
|
SingleStarredAssignment,
|
|
|
|
/// Represents a write to `__debug__`. This includes simple assignments and deletions as well
|
|
/// other kinds of statements that can introduce bindings, such as type parameters in functions,
|
|
/// classes, and aliases, `match` arms, and imports, among others.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// del __debug__
|
|
/// __debug__ = False
|
|
/// def f(__debug__): ...
|
|
/// class C[__debug__]: ...
|
|
/// ```
|
|
///
|
|
/// See [BPO 45000] for more information.
|
|
///
|
|
/// [BPO 45000]: https://github.com/python/cpython/issues/89163
|
|
WriteToDebug(WriteToDebugKind),
|
|
|
|
/// Represents the use of an invalid expression kind in one of several locations.
|
|
///
|
|
/// The kinds include `yield` and `yield from` expressions and named expressions, and locations
|
|
/// include type parameter bounds and defaults, type annotations, type aliases, and base class
|
|
/// lists.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// type X[T: (yield 1)] = int
|
|
/// type Y = (yield 1)
|
|
/// def f[T](x: int) -> (y := 3): return x
|
|
/// ```
|
|
InvalidExpression(InvalidExpressionKind, InvalidExpressionPosition),
|
|
|
|
/// Represents a duplicate key in a `match` mapping pattern.
|
|
///
|
|
/// The [CPython grammar] allows keys in mapping patterns to be literals or attribute accesses:
|
|
///
|
|
/// ```text
|
|
/// key_value_pattern:
|
|
/// | (literal_expr | attr) ':' pattern
|
|
/// ```
|
|
///
|
|
/// But only literals are checked for duplicates:
|
|
///
|
|
/// ```pycon
|
|
/// >>> match x:
|
|
/// ... case {"x": 1, "x": 2}: ...
|
|
/// ...
|
|
/// File "<python-input-160>", line 2
|
|
/// case {"x": 1, "x": 2}: ...
|
|
/// ^^^^^^^^^^^^^^^^
|
|
/// SyntaxError: mapping pattern checks duplicate key ('x')
|
|
/// >>> match x:
|
|
/// ... case {x.a: 1, x.a: 2}: ...
|
|
/// ...
|
|
/// >>>
|
|
/// ```
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// match x:
|
|
/// case {"x": 1, "x": 2}: ...
|
|
/// ```
|
|
///
|
|
/// [CPython grammar]: https://docs.python.org/3/reference/grammar.html
|
|
DuplicateMatchKey(String),
|
|
|
|
/// Represents a duplicate attribute name in a `match` class pattern.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// match x:
|
|
/// case Class(x=1, x=2): ...
|
|
/// ```
|
|
DuplicateMatchClassAttribute(ast::name::Name),
|
|
|
|
/// Represents the use of a `global` variable before its `global` declaration.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// counter = 1
|
|
/// def increment():
|
|
/// print(f"Adding 1 to {counter}")
|
|
/// global counter
|
|
/// counter += 1
|
|
/// ```
|
|
LoadBeforeGlobalDeclaration { name: String, start: TextSize },
|
|
|
|
/// Represents the use of a starred expression in an invalid location, such as a `return` or
|
|
/// `yield` statement.
|
|
///
|
|
/// ## Examples
|
|
///
|
|
/// ```python
|
|
/// def f(): return *x
|
|
/// def f(): yield *x
|
|
/// for _ in *x: ...
|
|
/// for *x in xs: ...
|
|
/// ```
|
|
InvalidStarExpression,
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
|
|
pub enum InvalidExpressionPosition {
|
|
TypeVarBound,
|
|
TypeVarDefault,
|
|
TypeVarTupleDefault,
|
|
ParamSpecDefault,
|
|
TypeAnnotation,
|
|
BaseClass,
|
|
GenericDefinition,
|
|
TypeAlias,
|
|
}
|
|
|
|
impl Display for InvalidExpressionPosition {
|
|
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
|
f.write_str(match self {
|
|
InvalidExpressionPosition::TypeVarBound => "TypeVar bound",
|
|
InvalidExpressionPosition::TypeVarDefault => "TypeVar default",
|
|
InvalidExpressionPosition::TypeVarTupleDefault => "TypeVarTuple default",
|
|
InvalidExpressionPosition::ParamSpecDefault => "ParamSpec default",
|
|
InvalidExpressionPosition::TypeAnnotation => "type annotation",
|
|
InvalidExpressionPosition::GenericDefinition => "generic definition",
|
|
InvalidExpressionPosition::BaseClass => "base class",
|
|
InvalidExpressionPosition::TypeAlias => "type alias",
|
|
})
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
|
|
pub enum InvalidExpressionKind {
|
|
Yield,
|
|
NamedExpr,
|
|
}
|
|
|
|
impl Display for InvalidExpressionKind {
|
|
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
|
f.write_str(match self {
|
|
InvalidExpressionKind::Yield => "yield expression",
|
|
InvalidExpressionKind::NamedExpr => "named expression",
|
|
})
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
|
|
pub enum WriteToDebugKind {
|
|
Store,
|
|
Delete(PythonVersion),
|
|
}
|
|
|
|
/// Searches for the first named expression (`x := y`) rebinding one of the `iteration_variables` in
|
|
/// a comprehension or generator expression.
|
|
struct ReboundComprehensionVisitor<'a> {
|
|
comprehensions: &'a [ast::Comprehension],
|
|
rebound_variables: Vec<TextRange>,
|
|
}
|
|
|
|
impl Visitor<'_> for ReboundComprehensionVisitor<'_> {
|
|
fn visit_expr(&mut self, expr: &Expr) {
|
|
if let Expr::Named(ast::ExprNamed { target, .. }) = expr {
|
|
if let Expr::Name(ast::ExprName { id, range, .. }) = &**target {
|
|
if self.comprehensions.iter().any(|comp| {
|
|
comp.target
|
|
.as_name_expr()
|
|
.is_some_and(|name| name.id == *id)
|
|
}) {
|
|
self.rebound_variables.push(*range);
|
|
}
|
|
}
|
|
}
|
|
walk_expr(self, expr);
|
|
}
|
|
}
|
|
|
|
struct MatchPatternVisitor<'a, Ctx> {
|
|
names: FxHashSet<&'a ast::name::Name>,
|
|
ctx: &'a Ctx,
|
|
}
|
|
|
|
impl<'a, Ctx: SemanticSyntaxContext> MatchPatternVisitor<'a, Ctx> {
|
|
fn visit_pattern(&mut self, pattern: &'a Pattern) {
|
|
// test_ok class_keyword_in_case_pattern
|
|
// match 2:
|
|
// case Class(x=x): ...
|
|
|
|
// test_err multiple_assignment_in_case_pattern
|
|
// match 2:
|
|
// case [y, z, y]: ... # MatchSequence
|
|
// case [y, z, *y]: ... # MatchSequence
|
|
// case [y, y, y]: ... # MatchSequence multiple
|
|
// case {1: x, 2: x}: ... # MatchMapping duplicate pattern
|
|
// case {1: x, **x}: ... # MatchMapping duplicate in **rest
|
|
// case Class(x, x): ... # MatchClass positional
|
|
// case Class(y=x, z=x): ... # MatchClass keyword
|
|
// case [x] | {1: x} | Class(y=x, z=x): ... # MatchOr
|
|
// case x as x: ... # MatchAs
|
|
match pattern {
|
|
Pattern::MatchValue(_) | Pattern::MatchSingleton(_) => {}
|
|
Pattern::MatchStar(ast::PatternMatchStar { name, .. }) => {
|
|
if let Some(name) = name {
|
|
self.insert(name);
|
|
}
|
|
}
|
|
Pattern::MatchSequence(ast::PatternMatchSequence { patterns, .. }) => {
|
|
for pattern in patterns {
|
|
self.visit_pattern(pattern);
|
|
}
|
|
}
|
|
Pattern::MatchMapping(ast::PatternMatchMapping {
|
|
keys,
|
|
patterns,
|
|
rest,
|
|
..
|
|
}) => {
|
|
for pattern in patterns {
|
|
self.visit_pattern(pattern);
|
|
}
|
|
if let Some(rest) = rest {
|
|
self.insert(rest);
|
|
}
|
|
|
|
let mut seen = FxHashSet::default();
|
|
for key in keys
|
|
.iter()
|
|
// complex numbers (`1 + 2j`) are allowed as keys but are not literals
|
|
// because they are represented as a `BinOp::Add` between a real number and
|
|
// an imaginary number
|
|
.filter(|key| key.is_literal_expr() || key.is_bin_op_expr())
|
|
{
|
|
if !seen.insert(ComparableExpr::from(key)) {
|
|
let key_range = key.range();
|
|
let duplicate_key = self.ctx.source()[key_range].to_string();
|
|
// test_ok duplicate_match_key_attr
|
|
// match x:
|
|
// case {x.a: 1, x.a: 2}: ...
|
|
|
|
// test_err duplicate_match_key
|
|
// match x:
|
|
// case {"x": 1, "x": 2}: ...
|
|
// case {b"x": 1, b"x": 2}: ...
|
|
// case {0: 1, 0: 2}: ...
|
|
// case {1.0: 1, 1.0: 2}: ...
|
|
// case {1.0 + 2j: 1, 1.0 + 2j: 2}: ...
|
|
// case {True: 1, True: 2}: ...
|
|
// case {None: 1, None: 2}: ...
|
|
// case {
|
|
// """x
|
|
// y
|
|
// z
|
|
// """: 1,
|
|
// """x
|
|
// y
|
|
// z
|
|
// """: 2}: ...
|
|
// case {"x": 1, "x": 2, "x": 3}: ...
|
|
// case {0: 1, "x": 1, 0: 2, "x": 2}: ...
|
|
// case [{"x": 1, "x": 2}]: ...
|
|
// case Foo(x=1, y={"x": 1, "x": 2}): ...
|
|
// case [Foo(x=1), Foo(x=1, y={"x": 1, "x": 2})]: ...
|
|
SemanticSyntaxChecker::add_error(
|
|
self.ctx,
|
|
SemanticSyntaxErrorKind::DuplicateMatchKey(duplicate_key),
|
|
key_range,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
Pattern::MatchClass(ast::PatternMatchClass { arguments, .. }) => {
|
|
for pattern in &arguments.patterns {
|
|
self.visit_pattern(pattern);
|
|
}
|
|
let mut seen = FxHashSet::default();
|
|
for keyword in &arguments.keywords {
|
|
if !seen.insert(&keyword.attr.id) {
|
|
// test_err duplicate_match_class_attr
|
|
// match x:
|
|
// case Class(x=1, x=2): ...
|
|
// case [Class(x=1, x=2)]: ...
|
|
// case {"x": x, "y": Foo(x=1, x=2)}: ...
|
|
// case [{}, {"x": x, "y": Foo(x=1, x=2)}]: ...
|
|
// case Class(x=1, d={"x": 1, "x": 2}, other=Class(x=1, x=2)): ...
|
|
SemanticSyntaxChecker::add_error(
|
|
self.ctx,
|
|
SemanticSyntaxErrorKind::DuplicateMatchClassAttribute(
|
|
keyword.attr.id.clone(),
|
|
),
|
|
keyword.attr.range,
|
|
);
|
|
}
|
|
self.visit_pattern(&keyword.pattern);
|
|
}
|
|
}
|
|
Pattern::MatchAs(ast::PatternMatchAs { pattern, name, .. }) => {
|
|
if let Some(pattern) = pattern {
|
|
self.visit_pattern(pattern);
|
|
}
|
|
if let Some(name) = name {
|
|
self.insert(name);
|
|
}
|
|
}
|
|
Pattern::MatchOr(ast::PatternMatchOr { patterns, .. }) => {
|
|
// each of these patterns should be visited separately because patterns can only be
|
|
// duplicated within a single arm of the or pattern. For example, the case below is
|
|
// a valid pattern.
|
|
|
|
// test_ok multiple_assignment_in_case_pattern
|
|
// match 2:
|
|
// case Class(x) | [x] | x: ...
|
|
for pattern in patterns {
|
|
let mut visitor = Self {
|
|
names: FxHashSet::default(),
|
|
ctx: self.ctx,
|
|
};
|
|
visitor.visit_pattern(pattern);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Add an identifier to the set of visited names in `self` and emit a [`SemanticSyntaxError`]
|
|
/// if `ident` has already been seen.
|
|
fn insert(&mut self, ident: &'a ast::Identifier) {
|
|
if !self.names.insert(&ident.id) {
|
|
SemanticSyntaxChecker::add_error(
|
|
self.ctx,
|
|
SemanticSyntaxErrorKind::MultipleCaseAssignment(ident.id.clone()),
|
|
ident.range(),
|
|
);
|
|
}
|
|
// test_err debug_shadow_match
|
|
// match x:
|
|
// case __debug__: ...
|
|
SemanticSyntaxChecker::check_identifier(ident, self.ctx);
|
|
}
|
|
}
|
|
|
|
struct InvalidExpressionVisitor<'a, Ctx> {
|
|
/// Allow named expressions (`x := ...`) to appear in annotations.
|
|
///
|
|
/// These are allowed in non-generic functions, for example:
|
|
///
|
|
/// ```python
|
|
/// def foo(arg: (x := int)): ... # ok
|
|
/// def foo[T](arg: (x := int)): ... # syntax error
|
|
/// ```
|
|
allow_named_expr: bool,
|
|
|
|
/// Context used for emitting errors.
|
|
ctx: &'a Ctx,
|
|
|
|
position: InvalidExpressionPosition,
|
|
}
|
|
|
|
impl<Ctx> Visitor<'_> for InvalidExpressionVisitor<'_, Ctx>
|
|
where
|
|
Ctx: SemanticSyntaxContext,
|
|
{
|
|
fn visit_expr(&mut self, expr: &Expr) {
|
|
match expr {
|
|
Expr::Named(ast::ExprNamed { range, .. }) if !self.allow_named_expr => {
|
|
SemanticSyntaxChecker::add_error(
|
|
self.ctx,
|
|
SemanticSyntaxErrorKind::InvalidExpression(
|
|
InvalidExpressionKind::NamedExpr,
|
|
self.position,
|
|
),
|
|
*range,
|
|
);
|
|
}
|
|
Expr::Yield(ast::ExprYield { range, .. })
|
|
| Expr::YieldFrom(ast::ExprYieldFrom { range, .. }) => {
|
|
SemanticSyntaxChecker::add_error(
|
|
self.ctx,
|
|
SemanticSyntaxErrorKind::InvalidExpression(
|
|
InvalidExpressionKind::Yield,
|
|
self.position,
|
|
),
|
|
*range,
|
|
);
|
|
}
|
|
_ => {}
|
|
}
|
|
ast::visitor::walk_expr(self, expr);
|
|
}
|
|
|
|
fn visit_type_param(&mut self, type_param: &ast::TypeParam) {
|
|
match type_param {
|
|
ast::TypeParam::TypeVar(ast::TypeParamTypeVar { bound, default, .. }) => {
|
|
if let Some(expr) = bound {
|
|
self.position = InvalidExpressionPosition::TypeVarBound;
|
|
self.visit_expr(expr);
|
|
}
|
|
if let Some(expr) = default {
|
|
self.position = InvalidExpressionPosition::TypeVarDefault;
|
|
self.visit_expr(expr);
|
|
}
|
|
}
|
|
ast::TypeParam::TypeVarTuple(ast::TypeParamTypeVarTuple { default, .. }) => {
|
|
if let Some(expr) = default {
|
|
self.position = InvalidExpressionPosition::TypeVarTupleDefault;
|
|
self.visit_expr(expr);
|
|
}
|
|
}
|
|
ast::TypeParam::ParamSpec(ast::TypeParamParamSpec { default, .. }) => {
|
|
if let Some(expr) = default {
|
|
self.position = InvalidExpressionPosition::ParamSpecDefault;
|
|
self.visit_expr(expr);
|
|
}
|
|
}
|
|
};
|
|
}
|
|
}
|
|
|
|
pub trait SemanticSyntaxContext {
|
|
/// Returns `true` if a module's docstring boundary has been passed.
|
|
fn seen_docstring_boundary(&self) -> bool;
|
|
|
|
/// The target Python version for detecting backwards-incompatible syntax changes.
|
|
fn python_version(&self) -> PythonVersion;
|
|
|
|
/// Returns the source text under analysis.
|
|
fn source(&self) -> &str;
|
|
|
|
/// Return the [`TextRange`] at which a name is declared as `global` in the current scope.
|
|
fn global(&self, name: &str) -> Option<TextRange>;
|
|
|
|
fn report_semantic_error(&self, error: SemanticSyntaxError);
|
|
}
|
|
|
|
#[derive(Default)]
|
|
pub struct SemanticSyntaxCheckerVisitor<Ctx> {
|
|
checker: SemanticSyntaxChecker,
|
|
context: Ctx,
|
|
}
|
|
|
|
impl<Ctx> SemanticSyntaxCheckerVisitor<Ctx> {
|
|
pub fn new(context: Ctx) -> Self {
|
|
Self {
|
|
checker: SemanticSyntaxChecker::new(),
|
|
context,
|
|
}
|
|
}
|
|
|
|
pub fn into_context(self) -> Ctx {
|
|
self.context
|
|
}
|
|
}
|
|
|
|
impl<Ctx> Visitor<'_> for SemanticSyntaxCheckerVisitor<Ctx>
|
|
where
|
|
Ctx: SemanticSyntaxContext,
|
|
{
|
|
fn visit_stmt(&mut self, stmt: &'_ Stmt) {
|
|
self.checker.visit_stmt(stmt, &self.context);
|
|
ruff_python_ast::visitor::walk_stmt(self, stmt);
|
|
}
|
|
|
|
fn visit_expr(&mut self, expr: &'_ Expr) {
|
|
self.checker.visit_expr(expr, &self.context);
|
|
ruff_python_ast::visitor::walk_expr(self, expr);
|
|
}
|
|
}
|
|
|
|
/// Modified version of [`std::str::EscapeDefault`] that does not escape single or double quotes.
|
|
struct EscapeDefault<'a>(&'a str);
|
|
|
|
impl Display for EscapeDefault<'_> {
|
|
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
|
use std::fmt::Write;
|
|
|
|
for c in self.0.chars() {
|
|
match c {
|
|
'\'' | '\"' => f.write_char(c)?,
|
|
_ => write!(f, "{}", c.escape_default())?,
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|