[syntax-errors] Parenthesized keyword argument names after Python 3.8

crates/ruff_python_parser/resources/inline/err/parenthesized_kwarg_py38.py

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

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

@@ -0,0 +1,2 @@
+# parse_options: {"target-version": "3.7"}
+f((a)=1)

crates/ruff_python_parser/src/error.rs

@@ -436,11 +436,6 @@ pub struct UnsupportedSyntaxError {
     pub kind: UnsupportedSyntaxErrorKind,
     pub range: TextRange,
     /// The target [`PythonVersion`] for which this error was detected.
-    ///
-    /// This is different from the version reported by the
-    /// [`minimum_version`](UnsupportedSyntaxErrorKind::minimum_version) method, which is the
-    /// earliest allowed version for this piece of syntax. The `target_version` is primarily used
-    /// for user-facing error messages.
     pub target_version: PythonVersion,
 }
 
@@ -449,6 +444,7 @@ pub enum UnsupportedSyntaxErrorKind {
     Match,
     Walrus,
     ExceptStar,
+    ParenthesizedKeywordArgumentName,
     /// Represents the use of a "relaxed" [PEP 614] decorator before Python 3.9.
     ///
     /// ## Examples
@@ -544,6 +540,9 @@ impl Display for UnsupportedSyntaxError {
             UnsupportedSyntaxErrorKind::Match => "Cannot use `match` statement",
             UnsupportedSyntaxErrorKind::Walrus => "Cannot use named assignment expression (`:=`)",
             UnsupportedSyntaxErrorKind::ExceptStar => "Cannot use `except*`",
+            UnsupportedSyntaxErrorKind::ParenthesizedKeywordArgumentName => {
+                "Cannot use parenthesized keyword argument name"
+            }
             UnsupportedSyntaxErrorKind::RelaxedDecorator => "Unsupported expression in decorators",
             UnsupportedSyntaxErrorKind::PositionalOnlyParameter => {
                 "Cannot use positional-only parameter separator"
@@ -554,27 +553,60 @@ impl Display for UnsupportedSyntaxError {
                 "Cannot set default type for a type parameter"
             }
         };
+
         write!(
             f,
-            "{kind} on Python {} (syntax was added in Python {})",
+            "{kind} on Python {} (syntax was {changed})",
             self.target_version,
-            self.kind.minimum_version(),
+            changed = self.kind.changed_version(),
         )
     }
 }
 
+/// Represents the kind of change in Python syntax between versions.
+///
+/// Most changes so far have been additions (e.g. `match` and `type` statements), but others are
+/// removals (e.g. parenthesized keyword argument names).
+enum Change {
+    Added(PythonVersion),
+    Removed(PythonVersion),
+}
+
+impl Display for Change {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Change::Added(version) => write!(f, "added in Python {version}"),
+            Change::Removed(version) => write!(f, "removed in Python {version}"),
+        }
+    }
+}
+
 impl UnsupportedSyntaxErrorKind {
-    /// The earliest allowed version for the syntax associated with this error.
-    pub const fn minimum_version(&self) -> PythonVersion {
+    /// Returns the Python version when the syntax associated with this error was changed, and the
+    /// type of [`Change`] (added or removed).
+    const fn changed_version(self) -> Change {
         match self {
-            UnsupportedSyntaxErrorKind::Match => PythonVersion::PY310,
-            UnsupportedSyntaxErrorKind::Walrus => PythonVersion::PY38,
-            UnsupportedSyntaxErrorKind::ExceptStar => PythonVersion::PY311,
-            UnsupportedSyntaxErrorKind::RelaxedDecorator => PythonVersion::PY39,
-            UnsupportedSyntaxErrorKind::PositionalOnlyParameter => PythonVersion::PY38,
-            UnsupportedSyntaxErrorKind::TypeParameterList => PythonVersion::PY312,
-            UnsupportedSyntaxErrorKind::TypeAliasStatement => PythonVersion::PY312,
-            UnsupportedSyntaxErrorKind::TypeParamDefault => PythonVersion::PY313,
+            UnsupportedSyntaxErrorKind::Match => Change::Added(PythonVersion::PY310),
+            UnsupportedSyntaxErrorKind::Walrus => Change::Added(PythonVersion::PY38),
+            UnsupportedSyntaxErrorKind::ExceptStar => Change::Added(PythonVersion::PY311),
+            UnsupportedSyntaxErrorKind::RelaxedDecorator => Change::Added(PythonVersion::PY39),
+            UnsupportedSyntaxErrorKind::PositionalOnlyParameter => {
+                Change::Added(PythonVersion::PY38)
+            }
+            UnsupportedSyntaxErrorKind::ParenthesizedKeywordArgumentName => {
+                Change::Removed(PythonVersion::PY38)
+            }
+            UnsupportedSyntaxErrorKind::TypeParameterList => Change::Added(PythonVersion::PY312),
+            UnsupportedSyntaxErrorKind::TypeAliasStatement => Change::Added(PythonVersion::PY312),
+            UnsupportedSyntaxErrorKind::TypeParamDefault => Change::Added(PythonVersion::PY313),
+        }
+    }
+
+    /// Returns whether or not this kind of syntax is unsupported on `target_version`.
+    pub(crate) fn is_unsupported(self, target_version: PythonVersion) -> bool {
+        match self.changed_version() {
+            Change::Added(version) => target_version < version,
+            Change::Removed(version) => target_version >= version,
         }
     }
 }

crates/ruff_python_parser/src/parser/expression.rs

@@ -405,7 +405,7 @@ impl<'src> Parser<'src> {
 
         ParsedExpr {
             expr: self.parse_postfix_expression(lhs.expr, start),
-            is_parenthesized: lhs.is_parenthesized,
+            end_parenthesis: lhs.end_parenthesis,
         }
     }
 
@@ -419,7 +419,7 @@ impl<'src> Parser<'src> {
     fn parse_expression_with_bitwise_or_precedence(&mut self) -> ParsedExpr {
         let parsed_expr = self.parse_conditional_expression_or_higher();
 
-        if parsed_expr.is_parenthesized {
+        if parsed_expr.is_parenthesized() {
             // Parentheses resets the precedence, so we don't need to validate it.
             return parsed_expr;
         }
@@ -703,7 +703,28 @@ impl<'src> Parser<'src> {
 
                 if parser.eat(TokenKind::Equal) {
                     seen_keyword_argument = true;
-                    let arg = if let Expr::Name(ident_expr) = parsed_expr.expr {
+                    let arg = if let ParsedExpr {
+                        expr: Expr::Name(ident_expr),
+                        end_parenthesis,
+                    } = parsed_expr
+                    {
+                        // test_ok parenthesized_kwarg_py37
+                        // # parse_options: {"target-version": "3.7"}
+                        // f((a)=1)
+
+                        // test_err parenthesized_kwarg_py38
+                        // # parse_options: {"target-version": "3.8"}
+                        // f((a)=1)
+                        // f((a) = 1)
+                        // f( ( a ) = 1)
+
+                        if let Some(end) = end_parenthesis {
+                            parser.add_unsupported_syntax_error(
+                                UnsupportedSyntaxErrorKind::ParenthesizedKeywordArgumentName,
+                                TextRange::new(start, end),
+                            );
+                        }
+
                         ast::Identifier {
                             id: ident_expr.id,
                             range: ident_expr.range,
@@ -857,7 +878,7 @@ impl<'src> Parser<'src> {
                 return lower.expr;
             }
 
-            if !lower.is_parenthesized {
+            if !lower.is_parenthesized() {
                 match lower.expr {
                     Expr::Starred(_) => {
                         self.add_error(ParseErrorType::InvalidStarredExpressionUsage, &lower);
@@ -1403,7 +1424,7 @@ impl<'src> Parser<'src> {
         // f"{*yield x}"
         let value = self.parse_expression_list(ExpressionContext::yield_or_starred_bitwise_or());
 
-        if !value.is_parenthesized && value.expr.is_lambda_expr() {
+        if !value.is_parenthesized() && value.expr.is_lambda_expr() {
             // TODO(dhruvmanila): This requires making some changes in lambda expression
             // parsing logic to handle the emitted `FStringMiddle` token in case the
             // lambda expression is not parenthesized.
@@ -1614,7 +1635,7 @@ impl<'src> Parser<'src> {
             TokenKind::Colon => {
                 // Now, we know that it's either a dictionary expression or a dictionary comprehension.
                 // In either case, the key is limited to an `expression`.
-                if !key_or_element.is_parenthesized {
+                if !key_or_element.is_parenthesized() {
                     match key_or_element.expr {
                         Expr::Starred(_) => self.add_error(
                             ParseErrorType::InvalidStarredExpressionUsage,
@@ -1693,7 +1714,7 @@ impl<'src> Parser<'src> {
 
                 ParsedExpr {
                     expr: tuple.into(),
-                    is_parenthesized: false,
+                    end_parenthesis: None,
                 }
             }
             TokenKind::Async | TokenKind::For => {
@@ -1713,7 +1734,7 @@ impl<'src> Parser<'src> {
 
                 ParsedExpr {
                     expr: generator,
-                    is_parenthesized: false,
+                    end_parenthesis: None,
                 }
             }
             _ => {
@@ -1724,7 +1745,7 @@ impl<'src> Parser<'src> {
 
                 self.expect(TokenKind::Rpar);
 
-                parsed_expr.is_parenthesized = true;
+                parsed_expr.end_parenthesis = Some(self.node_range(start).end());
                 parsed_expr
             }
         }
@@ -2330,13 +2351,19 @@ impl<'src> Parser<'src> {
 #[derive(Debug)]
 pub(super) struct ParsedExpr {
     pub(super) expr: Expr,
-    pub(super) is_parenthesized: bool,
+    /// Contains the location of the closing parenthesis, if the expression is parenthesized
+    pub(super) end_parenthesis: Option<TextSize>,
 }
 
 impl ParsedExpr {
     #[inline]
     pub(super) const fn is_unparenthesized_starred_expr(&self) -> bool {
-        !self.is_parenthesized && self.expr.is_starred_expr()
+        !self.is_parenthesized() && self.expr.is_starred_expr()
+    }
+
+    #[inline]
+    pub(super) const fn is_parenthesized(&self) -> bool {
+        self.end_parenthesis.is_some()
     }
 }
 
@@ -2345,7 +2372,7 @@ impl From<Expr> for ParsedExpr {
     fn from(expr: Expr) -> Self {
         ParsedExpr {
             expr,
-            is_parenthesized: false,
+            end_parenthesis: None,
         }
     }
 }

crates/ruff_python_parser/src/parser/mod.rs

@@ -441,7 +441,7 @@ impl<'src> Parser<'src> {
     /// Add an [`UnsupportedSyntaxError`] with the given [`UnsupportedSyntaxErrorKind`] and
     /// [`TextRange`] if its minimum version is less than [`Parser::target_version`].
     fn add_unsupported_syntax_error(&mut self, kind: UnsupportedSyntaxErrorKind, range: TextRange) {
-        if self.options.target_version < kind.minimum_version() {
+        if kind.is_unsupported(self.options.target_version) {
             self.unsupported_syntax_errors.push(UnsupportedSyntaxError {
                 kind,
                 range,

crates/ruff_python_parser/src/parser/statement.rs

@@ -1020,7 +1020,7 @@ impl<'src> Parser<'src> {
             IpyEscapeKind::Help
         };
 
-        if parsed_expr.is_parenthesized {
+        if parsed_expr.is_parenthesized() {
             let token_range = self.node_range(start);
             self.add_error(
                 ParseErrorType::OtherError(
@@ -1151,7 +1151,7 @@ impl<'src> Parser<'src> {
         // (a): int
         // a.b: int
         // a[0]: int
-        let simple = target.is_name_expr() && !target.is_parenthesized;
+        let simple = target.is_name_expr() && !target.is_parenthesized();
 
         // test_err ann_assign_stmt_invalid_annotation
         // x: *int = 1
@@ -2201,7 +2201,7 @@ impl<'src> Parser<'src> {
             .then(|| Box::new(self.parse_with_item_optional_vars().expr));
 
         ParsedWithItem {
-            is_parenthesized: context_expr.is_parenthesized,
+            is_parenthesized: context_expr.is_parenthesized(),
             item: ast::WithItem {
                 range: self.node_range(start),
                 context_expr: context_expr.expr,