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[syntax-errors] Parenthesized keyword argument names after Python 3.8 (#16482)
Summary -- Unlike the other syntax errors detected so far, parenthesized keyword arguments are only allowed *before* 3.8. It sounds like they were only accidentally allowed before that [^1]. As an aside, you get a pretty confusing error from Python for this, so it's nice that we can catch it: ```pycon >>> def f(**kwargs): ... ... f((a)=1) ... File "<python-input-0>", line 2 f((a)=1) ^^^ SyntaxError: expression cannot contain assignment, perhaps you meant "=="? >>> ``` Test Plan -- Inline tests. [^1]: python/cpython#78822
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‎crates/ruff_python_parser/resources/inline/err/parenthesized_kwarg_py38.py

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@@ -0,0 +1,4 @@
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# parse_options: {"target-version": "3.8"}
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f((a)=1)
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f((a) = 1)
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f( ( a ) = 1)

‎crates/ruff_python_parser/resources/inline/ok/parenthesized_kwarg_py37.py

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# parse_options: {"target-version": "3.7"}
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f((a)=1)

‎crates/ruff_python_parser/src/error.rs

Lines changed: 71 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -436,11 +436,6 @@ pub struct UnsupportedSyntaxError {
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pub kind: UnsupportedSyntaxErrorKind,
437437
pub range: TextRange,
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/// The target [`PythonVersion`] for which this error was detected.
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///
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/// This is different from the version reported by the
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/// [`minimum_version`](UnsupportedSyntaxErrorKind::minimum_version) method, which is the
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/// earliest allowed version for this piece of syntax. The `target_version` is primarily used
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/// for user-facing error messages.
444439
pub target_version: PythonVersion,
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}
446441

@@ -457,6 +452,26 @@ pub enum UnsupportedSyntaxErrorKind {
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Walrus,
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ExceptStar,
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/// Represents the use of a parenthesized keyword argument name after Python 3.8.
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///
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/// ## Example
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///
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/// From [BPO 34641] it sounds like this was only accidentally supported and was removed when
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/// noticed. Code like this used to be valid:
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///
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/// ```python
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/// f((a)=1)
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/// ```
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///
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/// After Python 3.8, you have to omit the parentheses around `a`:
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///
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/// ```python
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/// f(a=1)
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/// ```
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///
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/// [BPO 34641]: https://github.com/python/cpython/issues/78822
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ParenthesizedKeywordArgumentName,
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/// Represents the use of unparenthesized tuple unpacking in a `return` statement or `yield`
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/// expression before Python 3.8.
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///
@@ -603,6 +618,9 @@ impl Display for UnsupportedSyntaxError {
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UnsupportedSyntaxErrorKind::Match => "Cannot use `match` statement",
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UnsupportedSyntaxErrorKind::Walrus => "Cannot use named assignment expression (`:=`)",
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UnsupportedSyntaxErrorKind::ExceptStar => "Cannot use `except*`",
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UnsupportedSyntaxErrorKind::ParenthesizedKeywordArgumentName => {
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"Cannot use parenthesized keyword argument name"
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}
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UnsupportedSyntaxErrorKind::StarTuple(StarTupleKind::Return) => {
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"Cannot use iterable unpacking in return statements"
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}
@@ -619,30 +637,65 @@ impl Display for UnsupportedSyntaxError {
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"Cannot set default type for a type parameter"
620638
}
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};
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622641
write!(
623642
f,
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"{kind} on Python {} (syntax was added in Python {})",
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"{kind} on Python {} (syntax was {changed})",
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self.target_version,
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self.kind.minimum_version(),
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changed = self.kind.changed_version(),
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)
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}
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}
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/// Represents the kind of change in Python syntax between versions.
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enum Change {
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Added(PythonVersion),
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Removed(PythonVersion),
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}
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impl Display for Change {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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match self {
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Change::Added(version) => write!(f, "added in Python {version}"),
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Change::Removed(version) => write!(f, "removed in Python {version}"),
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}
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}
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}
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impl UnsupportedSyntaxErrorKind {
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/// The earliest allowed version for the syntax associated with this error.
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pub const fn minimum_version(&self) -> PythonVersion {
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/// Returns the Python version when the syntax associated with this error was changed, and the
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/// type of [`Change`] (added or removed).
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const fn changed_version(self) -> Change {
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match self {
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UnsupportedSyntaxErrorKind::Match => PythonVersion::PY310,
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UnsupportedSyntaxErrorKind::Walrus => PythonVersion::PY38,
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UnsupportedSyntaxErrorKind::ExceptStar => PythonVersion::PY311,
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UnsupportedSyntaxErrorKind::StarTuple(_) => PythonVersion::PY38,
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UnsupportedSyntaxErrorKind::RelaxedDecorator => PythonVersion::PY39,
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UnsupportedSyntaxErrorKind::PositionalOnlyParameter => PythonVersion::PY38,
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UnsupportedSyntaxErrorKind::TypeParameterList => PythonVersion::PY312,
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UnsupportedSyntaxErrorKind::TypeAliasStatement => PythonVersion::PY312,
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UnsupportedSyntaxErrorKind::TypeParamDefault => PythonVersion::PY313,
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UnsupportedSyntaxErrorKind::Match => Change::Added(PythonVersion::PY310),
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UnsupportedSyntaxErrorKind::Walrus => Change::Added(PythonVersion::PY38),
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UnsupportedSyntaxErrorKind::ExceptStar => Change::Added(PythonVersion::PY311),
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UnsupportedSyntaxErrorKind::StarTuple(_) => Change::Added(PythonVersion::PY38),
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UnsupportedSyntaxErrorKind::RelaxedDecorator => Change::Added(PythonVersion::PY39),
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UnsupportedSyntaxErrorKind::PositionalOnlyParameter => {
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Change::Added(PythonVersion::PY38)
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}
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UnsupportedSyntaxErrorKind::ParenthesizedKeywordArgumentName => {
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Change::Removed(PythonVersion::PY38)
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}
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UnsupportedSyntaxErrorKind::TypeParameterList => Change::Added(PythonVersion::PY312),
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UnsupportedSyntaxErrorKind::TypeAliasStatement => Change::Added(PythonVersion::PY312),
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UnsupportedSyntaxErrorKind::TypeParamDefault => Change::Added(PythonVersion::PY313),
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}
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}
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/// Returns whether or not this kind of syntax is unsupported on `target_version`.
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pub(crate) fn is_unsupported(self, target_version: PythonVersion) -> bool {
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match self.changed_version() {
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Change::Added(version) => target_version < version,
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Change::Removed(version) => target_version >= version,
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}
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}
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/// Returns `true` if this kind of syntax is supported on `target_version`.
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pub(crate) fn is_supported(self, target_version: PythonVersion) -> bool {
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!self.is_unsupported(target_version)
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}
646699
}
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648701
#[cfg(target_pointer_width = "64")]

‎crates/ruff_python_parser/src/parser/expression.rs

Lines changed: 23 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -702,9 +702,31 @@ impl<'src> Parser<'src> {
702702
}
703703
}
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let arg_range = parser.node_range(start);
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if parser.eat(TokenKind::Equal) {
706707
seen_keyword_argument = true;
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let arg = if let Expr::Name(ident_expr) = parsed_expr.expr {
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let arg = if let ParsedExpr {
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expr: Expr::Name(ident_expr),
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is_parenthesized,
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} = parsed_expr
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{
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// test_ok parenthesized_kwarg_py37
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// # parse_options: {"target-version": "3.7"}
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// f((a)=1)
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// test_err parenthesized_kwarg_py38
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// # parse_options: {"target-version": "3.8"}
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// f((a)=1)
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// f((a) = 1)
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// f( ( a ) = 1)
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723+
if is_parenthesized {
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parser.add_unsupported_syntax_error(
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UnsupportedSyntaxErrorKind::ParenthesizedKeywordArgumentName,
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arg_range,
727+
);
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}
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ast::Identifier {
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id: ident_expr.id,
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range: ident_expr.range,

‎crates/ruff_python_parser/src/parser/mod.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -441,7 +441,7 @@ impl<'src> Parser<'src> {
441441
/// Add an [`UnsupportedSyntaxError`] with the given [`UnsupportedSyntaxErrorKind`] and
442442
/// [`TextRange`] if its minimum version is less than [`Parser::target_version`].
443443
fn add_unsupported_syntax_error(&mut self, kind: UnsupportedSyntaxErrorKind, range: TextRange) {
444-
if self.options.target_version < kind.minimum_version() {
444+
if kind.is_unsupported(self.options.target_version) {
445445
self.unsupported_syntax_errors.push(UnsupportedSyntaxError {
446446
kind,
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range,

‎crates/ruff_python_parser/src/parser/statement.rs

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Original file line numberDiff line numberDiff line change
@@ -424,7 +424,7 @@ impl<'src> Parser<'src> {
424424
/// are only allowed in Python 3.8 and later: <https://github.com/python/cpython/issues/76298>.
425425
pub(crate) fn check_tuple_unpacking(&mut self, expr: &Expr, kind: StarTupleKind) {
426426
let kind = UnsupportedSyntaxErrorKind::StarTuple(kind);
427-
if self.options.target_version >= kind.minimum_version() {
427+
if kind.is_supported(self.options.target_version) {
428428
return;
429429
}
430430

‎crates/ruff_python_parser/tests/snapshots/invalid_syntax@parenthesized_kwarg_py38.py.snap

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---
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source: crates/ruff_python_parser/tests/fixtures.rs
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input_file: crates/ruff_python_parser/resources/inline/err/parenthesized_kwarg_py38.py
4+
---
5+
## AST
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7+
```
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Module(
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ModModule {
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range: 0..77,
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body: [
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Expr(
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StmtExpr {
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range: 43..51,
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value: Call(
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ExprCall {
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range: 43..51,
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func: Name(
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ExprName {
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range: 43..44,
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id: Name("f"),
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ctx: Load,
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},
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),
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arguments: Arguments {
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range: 44..51,
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args: [],
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keywords: [
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Keyword {
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range: 45..50,
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arg: Some(
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Identifier {
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id: Name("a"),
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range: 46..47,
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},
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),
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value: NumberLiteral(
38+
ExprNumberLiteral {
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range: 49..50,
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value: Int(
41+
1,
42+
),
43+
},
44+
),
45+
},
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],
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},
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},
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),
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},
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),
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Expr(
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StmtExpr {
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range: 52..62,
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value: Call(
56+
ExprCall {
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range: 52..62,
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func: Name(
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ExprName {
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range: 52..53,
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id: Name("f"),
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ctx: Load,
63+
},
64+
),
65+
arguments: Arguments {
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range: 53..62,
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args: [],
68+
keywords: [
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Keyword {
70+
range: 54..61,
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arg: Some(
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Identifier {
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id: Name("a"),
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range: 55..56,
75+
},
76+
),
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value: NumberLiteral(
78+
ExprNumberLiteral {
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range: 60..61,
80+
value: Int(
81+
1,
82+
),
83+
},
84+
),
85+
},
86+
],
87+
},
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},
89+
),
90+
},
91+
),
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Expr(
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StmtExpr {
94+
range: 63..76,
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value: Call(
96+
ExprCall {
97+
range: 63..76,
98+
func: Name(
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ExprName {
100+
range: 63..64,
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id: Name("f"),
102+
ctx: Load,
103+
},
104+
),
105+
arguments: Arguments {
106+
range: 64..76,
107+
args: [],
108+
keywords: [
109+
Keyword {
110+
range: 66..75,
111+
arg: Some(
112+
Identifier {
113+
id: Name("a"),
114+
range: 68..69,
115+
},
116+
),
117+
value: NumberLiteral(
118+
ExprNumberLiteral {
119+
range: 74..75,
120+
value: Int(
121+
1,
122+
),
123+
},
124+
),
125+
},
126+
],
127+
},
128+
},
129+
),
130+
},
131+
),
132+
],
133+
},
134+
)
135+
```
136+
## Unsupported Syntax Errors
137+
138+
|
139+
1 | # parse_options: {"target-version": "3.8"}
140+
2 | f((a)=1)
141+
| ^^^ Syntax Error: Cannot use parenthesized keyword argument name on Python 3.8 (syntax was removed in Python 3.8)
142+
3 | f((a) = 1)
143+
4 | f( ( a ) = 1)
144+
|
145+
146+
147+
|
148+
1 | # parse_options: {"target-version": "3.8"}
149+
2 | f((a)=1)
150+
3 | f((a) = 1)
151+
| ^^^ Syntax Error: Cannot use parenthesized keyword argument name on Python 3.8 (syntax was removed in Python 3.8)
152+
4 | f( ( a ) = 1)
153+
|
154+
155+
156+
|
157+
2 | f((a)=1)
158+
3 | f((a) = 1)
159+
4 | f( ( a ) = 1)
160+
| ^^^^^ Syntax Error: Cannot use parenthesized keyword argument name on Python 3.8 (syntax was removed in Python 3.8)
161+
|

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