Add a specialized StatementVisitor (#4349)

crates/ruff/src/checkers/imports.rs

@@ -8,7 +8,7 @@ use ruff_diagnostics::Diagnostic;
 use ruff_python_ast::helpers::to_module_path;
 use ruff_python_ast::imports::{ImportMap, ModuleImport};
 use ruff_python_ast::source_code::{Indexer, Locator, Stylist};
-use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::statement_visitor::StatementVisitor;
 use ruff_python_stdlib::path::is_python_stub_file;
 
 use crate::directives::IsortDirectives;

crates/ruff/src/doc_lines.rs

@@ -10,8 +10,7 @@ use rustpython_parser::Tok;
 
 use ruff_python_ast::newlines::UniversalNewlineIterator;
 use ruff_python_ast::source_code::Locator;
-use ruff_python_ast::visitor;
+use ruff_python_ast::statement_visitor::{walk_stmt, StatementVisitor};
-use ruff_python_ast::visitor::Visitor;
 
 /// Extract doc lines (standalone comments) from a token sequence.
 pub fn doc_lines_from_tokens<'a>(lxr: &'a [LexResult], locator: &'a Locator<'a>) -> DocLines<'a> {
@@ -75,7 +74,7 @@ struct StringLinesVisitor<'a> {
     locator: &'a Locator<'a>,
 }
 
-impl Visitor<'_> for StringLinesVisitor<'_> {
+impl StatementVisitor<'_> for StringLinesVisitor<'_> {
     fn visit_stmt(&mut self, stmt: &Stmt) {
         if let StmtKind::Expr { value } = &stmt.node {
             if let ExprKind::Constant {
@@ -91,7 +90,7 @@ impl Visitor<'_> for StringLinesVisitor<'_> {
                 }
             }
         }
-        visitor::walk_stmt(self, stmt);
+        walk_stmt(self, stmt);
     }
 }
 

crates/ruff/src/rules/flake8_annotations/rules.rs

@@ -3,7 +3,7 @@ use rustpython_parser::ast::{Constant, Expr, ExprKind, Stmt};
 use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::ReturnStatementVisitor;
-use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::statement_visitor::StatementVisitor;
 use ruff_python_ast::{cast, helpers};
 use ruff_python_semantic::analyze::visibility;
 use ruff_python_semantic::analyze::visibility::Visibility;
@@ -416,9 +416,7 @@ impl Violation for AnyType {
 
 fn is_none_returning(body: &[Stmt]) -> bool {
     let mut visitor = ReturnStatementVisitor::default();
-    for stmt in body {
+    visitor.visit_body(body);
-        visitor.visit_stmt(stmt);
-    }
     for expr in visitor.returns.into_iter().flatten() {
         if !matches!(
             expr.node,

crates/ruff/src/rules/flake8_bugbear/rules/raise_without_from_inside_except.rs

@@ -3,7 +3,7 @@ use rustpython_parser::ast::{ExprKind, Stmt};
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::RaiseStatementVisitor;
-use ruff_python_ast::visitor;
+use ruff_python_ast::statement_visitor::StatementVisitor;
 use ruff_python_stdlib::str::is_lower;
 
 use crate::checkers::ast::Checker;
@@ -25,7 +25,7 @@ impl Violation for RaiseWithoutFromInsideExcept {
 pub fn raise_without_from_inside_except(checker: &mut Checker, body: &[Stmt]) {
     let raises = {
         let mut visitor = RaiseStatementVisitor::default();
-        visitor::walk_body(&mut visitor, body);
+        visitor.visit_body(body);
         visitor.raises
     };
 

crates/ruff/src/rules/isort/track.rs

@@ -1,12 +1,8 @@
 use ruff_text_size::{TextRange, TextSize};
-use rustpython_parser::ast::{
+use rustpython_parser::ast::{Excepthandler, ExcepthandlerKind, MatchCase, Stmt, StmtKind};
-    Alias, Arg, Arguments, Boolop, Cmpop, Comprehension, Constant, Excepthandler,
-    ExcepthandlerKind, Expr, ExprContext, Keyword, MatchCase, Operator, Pattern, Stmt, StmtKind,
-    Unaryop, Withitem,
-};
 
 use ruff_python_ast::source_code::Locator;
-use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::statement_visitor::StatementVisitor;
 
 use crate::directives::IsortDirectives;
 use crate::rules::isort::helpers;
@@ -111,7 +107,7 @@ impl<'a> ImportTracker<'a> {
     }
 }
 
-impl<'a, 'b> Visitor<'b> for ImportTracker<'a>
+impl<'a, 'b> StatementVisitor<'b> for ImportTracker<'a>
 where
     'b: 'a,
 {
@@ -226,8 +222,7 @@ where
                 }
                 self.finalize(None);
             }
-            StmtKind::Match { subject, cases } => {
+            StmtKind::Match { cases, .. } => {
-                self.visit_expr(subject);
                 for match_case in cases {
                     self.visit_match_case(match_case);
                 }
@@ -268,24 +263,6 @@ where
         self.nested = prev_nested;
     }
 
-    fn visit_annotation(&mut self, _: &'b Expr) {}
-
-    fn visit_expr(&mut self, _: &'b Expr) {}
-
-    fn visit_constant(&mut self, _: &'b Constant) {}
-
-    fn visit_expr_context(&mut self, _: &'b ExprContext) {}
-
-    fn visit_boolop(&mut self, _: &'b Boolop) {}
-
-    fn visit_operator(&mut self, _: &'b Operator) {}
-
-    fn visit_unaryop(&mut self, _: &'b Unaryop) {}
-
-    fn visit_cmpop(&mut self, _: &'b Cmpop) {}
-
-    fn visit_comprehension(&mut self, _: &'b Comprehension) {}
-
     fn visit_excepthandler(&mut self, excepthandler: &'b Excepthandler) {
         let prev_nested = self.nested;
         self.nested = true;
@@ -299,22 +276,10 @@ where
         self.nested = prev_nested;
     }
 
-    fn visit_arguments(&mut self, _: &'b Arguments) {}
-
-    fn visit_arg(&mut self, _: &'b Arg) {}
-
-    fn visit_keyword(&mut self, _: &'b Keyword) {}
-
-    fn visit_alias(&mut self, _: &'b Alias) {}
-
-    fn visit_withitem(&mut self, _: &'b Withitem) {}
-
     fn visit_match_case(&mut self, match_case: &'b MatchCase) {
         for stmt in &match_case.body {
             self.visit_stmt(stmt);
         }
         self.finalize(None);
     }
-
-    fn visit_pattern(&mut self, _: &'b Pattern) {}
 }

crates/ruff/src/rules/pylint/rules/redefined_loop_name.rs

@@ -7,9 +7,8 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::comparable::ComparableExpr;
 use ruff_python_ast::helpers::unparse_expr;
+use ruff_python_ast::statement_visitor::{walk_stmt, StatementVisitor};
 use ruff_python_ast::types::Node;
-use ruff_python_ast::visitor;
-use ruff_python_ast::visitor::Visitor;
 use ruff_python_semantic::context::Context;
 
 use crate::checkers::ast::Checker;
@@ -146,7 +145,7 @@ struct InnerForWithAssignTargetsVisitor<'a> {
     assignment_targets: Vec<ExprWithInnerBindingKind<'a>>,
 }
 
-impl<'a, 'b> Visitor<'b> for InnerForWithAssignTargetsVisitor<'a>
+impl<'a, 'b> StatementVisitor<'b> for InnerForWithAssignTargetsVisitor<'a>
 where
     'b: 'a,
 {
@@ -225,7 +224,7 @@ where
             StmtKind::FunctionDef { .. } => {}
             // Otherwise, do recurse.
             _ => {
-                visitor::walk_stmt(self, stmt);
+                walk_stmt(self, stmt);
             }
         }
     }

crates/ruff/src/rules/pylint/rules/too_many_return_statements.rs

@@ -4,7 +4,7 @@ use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::{identifier_range, ReturnStatementVisitor};
 use ruff_python_ast::source_code::Locator;
-use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::statement_visitor::StatementVisitor;
 
 #[violation]
 pub struct TooManyReturnStatements {

crates/ruff/src/rules/pylint/rules/useless_return.rs

@@ -4,8 +4,8 @@ use rustpython_parser::ast::{Constant, Expr, ExprKind, Stmt, StmtKind};
 use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::{is_const_none, ReturnStatementVisitor};
+use ruff_python_ast::statement_visitor::StatementVisitor;
 use ruff_python_ast::types::RefEquality;
-use ruff_python_ast::visitor::Visitor;
 
 use crate::autofix::actions::delete_stmt;
 use crate::checkers::ast::Checker;

crates/ruff/src/rules/pyupgrade/rules/yield_in_for_loop.rs

@@ -3,9 +3,10 @@ use rustpython_parser::ast::{Expr, ExprContext, ExprKind, Stmt, StmtKind};
 
 use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::statement_visitor::StatementVisitor;
 use ruff_python_ast::types::RefEquality;
-use ruff_python_ast::visitor;
 use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::{statement_visitor, visitor};
 
 use crate::checkers::ast::Checker;
 use crate::registry::AsRule;
@@ -59,7 +60,7 @@ struct YieldFromVisitor<'a> {
     yields: Vec<YieldFrom<'a>>,
 }
 
-impl<'a> Visitor<'a> for YieldFromVisitor<'a> {
+impl<'a> StatementVisitor<'a> for YieldFromVisitor<'a> {
     fn visit_stmt(&mut self, stmt: &'a Stmt) {
         match &stmt.node {
             StmtKind::For {
@@ -97,20 +98,7 @@ impl<'a> Visitor<'a> for YieldFromVisitor<'a> {
             | StmtKind::ClassDef { .. } => {
                 // Don't recurse into anything that defines a new scope.
             }
-            _ => visitor::walk_stmt(self, stmt),
+            _ => statement_visitor::walk_stmt(self, stmt),
-        }
-    }
-
-    fn visit_expr(&mut self, expr: &'a Expr) {
-        match &expr.node {
-            ExprKind::ListComp { .. }
-            | ExprKind::SetComp { .. }
-            | ExprKind::DictComp { .. }
-            | ExprKind::GeneratorExp { .. }
-            | ExprKind::Lambda { .. } => {
-                // Don't recurse into anything that defines a new scope.
-            }
-            _ => visitor::walk_expr(self, expr),
         }
     }
 }

crates/ruff/src/rules/tryceratops/rules/raise_within_try.rs

@@ -2,7 +2,7 @@ use rustpython_parser::ast::{Excepthandler, Stmt, StmtKind};
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::visitor::{self, Visitor};
+use ruff_python_ast::statement_visitor::{walk_stmt, StatementVisitor};
 
 use crate::checkers::ast::Checker;
 
@@ -58,7 +58,7 @@ struct RaiseStatementVisitor<'a> {
     raises: Vec<&'a Stmt>,
 }
 
-impl<'a, 'b> Visitor<'b> for RaiseStatementVisitor<'a>
+impl<'a, 'b> StatementVisitor<'b> for RaiseStatementVisitor<'a>
 where
     'b: 'a,
 {
@@ -66,7 +66,7 @@ where
         match stmt.node {
             StmtKind::Raise { .. } => self.raises.push(stmt),
             StmtKind::Try { .. } | StmtKind::TryStar { .. } => (),
-            _ => visitor::walk_stmt(self, stmt),
+            _ => walk_stmt(self, stmt),
         }
     }
 }
@@ -79,9 +79,7 @@ pub fn raise_within_try(checker: &mut Checker, body: &[Stmt], handlers: &[Except
 
     let raises = {
         let mut visitor = RaiseStatementVisitor::default();
-        for stmt in body {
+        visitor.visit_body(body);
-            visitor.visit_stmt(stmt);
-        }
         visitor.raises
     };
 

crates/ruff/src/rules/tryceratops/rules/reraise_no_cause.rs

@@ -3,7 +3,7 @@ use rustpython_parser::ast::{ExprKind, Stmt};
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::RaiseStatementVisitor;
-use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::statement_visitor::StatementVisitor;
 
 use crate::checkers::ast::Checker;
 
@@ -50,9 +50,7 @@ impl Violation for ReraiseNoCause {
 pub fn reraise_no_cause(checker: &mut Checker, body: &[Stmt]) {
     let raises = {
         let mut visitor = RaiseStatementVisitor::default();
-        for stmt in body {
+        visitor.visit_body(body);
-            visitor.visit_stmt(stmt);
-        }
         visitor.raises
     };
 

crates/ruff/src/rules/tryceratops/rules/type_check_without_type_error.rs

@@ -2,8 +2,7 @@ use rustpython_parser::ast::{Expr, ExprKind, Stmt, StmtKind};
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::visitor;
+use ruff_python_ast::statement_visitor::{walk_stmt, StatementVisitor};
-use ruff_python_ast::visitor::Visitor;
 
 use crate::checkers::ast::Checker;
 
@@ -51,7 +50,7 @@ struct ControlFlowVisitor<'a> {
     continues: Vec<&'a Stmt>,
 }
 
-impl<'a, 'b> Visitor<'b> for ControlFlowVisitor<'a>
+impl<'a, 'b> StatementVisitor<'b> for ControlFlowVisitor<'a>
 where
     'b: 'a,
 {
@@ -65,19 +64,7 @@ where
             StmtKind::Return { .. } => self.returns.push(stmt),
             StmtKind::Break => self.breaks.push(stmt),
             StmtKind::Continue => self.continues.push(stmt),
-            _ => visitor::walk_stmt(self, stmt),
+            _ => walk_stmt(self, stmt),
-        }
-    }
-
-    fn visit_expr(&mut self, expr: &'b Expr) {
-        match &expr.node {
-            ExprKind::ListComp { .. }
-            | ExprKind::DictComp { .. }
-            | ExprKind::SetComp { .. }
-            | ExprKind::GeneratorExp { .. } => {
-                // Don't recurse.
-            }
-            _ => visitor::walk_expr(self, expr),
         }
     }
 }

crates/ruff/src/rules/tryceratops/rules/verbose_raise.rs

@@ -2,8 +2,7 @@ use rustpython_parser::ast::{Excepthandler, ExcepthandlerKind, Expr, ExprKind, S
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::visitor;
+use ruff_python_ast::statement_visitor::{walk_stmt, StatementVisitor};
-use ruff_python_ast::visitor::Visitor;
 
 use crate::checkers::ast::Checker;
 
@@ -46,7 +45,7 @@ struct RaiseStatementVisitor<'a> {
     raises: Vec<(Option<&'a Expr>, Option<&'a Expr>)>,
 }
 
-impl<'a, 'b> Visitor<'b> for RaiseStatementVisitor<'a>
+impl<'a, 'b> StatementVisitor<'b> for RaiseStatementVisitor<'a>
 where
     'b: 'a,
 {
@@ -60,10 +59,10 @@ where
                 body, finalbody, ..
             } => {
                 for stmt in body.iter().chain(finalbody.iter()) {
-                    visitor::walk_stmt(self, stmt);
+                    walk_stmt(self, stmt);
                 }
             }
-            _ => visitor::walk_stmt(self, stmt),
+            _ => walk_stmt(self, stmt),
         }
     }
 }
@@ -80,9 +79,7 @@ pub fn verbose_raise(checker: &mut Checker, handlers: &[Excepthandler]) {
         {
             let raises = {
                 let mut visitor = RaiseStatementVisitor::default();
-                for stmt in body {
+                visitor.visit_body(body);
-                    visitor.visit_stmt(stmt);
-                }
                 visitor.raises
             };
             for (exc, cause) in raises {

crates/ruff_benchmark/benches/parser.rs

@@ -1,7 +1,7 @@
 use criterion::measurement::WallTime;
 use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
 use ruff_benchmark::{TestCase, TestCaseSpeed, TestFile, TestFileDownloadError};
-use ruff_python_ast::visitor::{walk_stmt, Visitor};
+use ruff_python_ast::statement_visitor::{walk_stmt, StatementVisitor};
 use rustpython_parser::ast::Stmt;
 use std::time::Duration;
 
@@ -40,7 +40,7 @@ struct CountVisitor {
     count: usize,
 }
 
-impl<'a> Visitor<'a> for CountVisitor {
+impl<'a> StatementVisitor<'a> for CountVisitor {
     fn visit_stmt(&mut self, stmt: &'a Stmt) {
         walk_stmt(self, stmt);
         self.count += 1;

crates/ruff_python_ast/src/helpers.rs

@@ -18,8 +18,7 @@ use smallvec::SmallVec;
 use crate::call_path::CallPath;
 use crate::newlines::UniversalNewlineIterator;
 use crate::source_code::{Generator, Indexer, Locator, Stylist};
-use crate::visitor;
+use crate::statement_visitor::{walk_body, walk_stmt, StatementVisitor};
-use crate::visitor::Visitor;
 
 /// Create an `Expr` with default location from an `ExprKind`.
 pub fn create_expr(node: ExprKind) -> Expr {
@@ -816,13 +815,13 @@ pub fn resolve_imported_module_path<'a>(
     Some(Cow::Owned(qualified_path))
 }
 
-/// A [`Visitor`] that collects all `return` statements in a function or method.
+/// A [`StatementVisitor`] that collects all `return` statements in a function or method.
 #[derive(Default)]
 pub struct ReturnStatementVisitor<'a> {
     pub returns: Vec<Option<&'a Expr>>,
 }
 
-impl<'a, 'b> Visitor<'b> for ReturnStatementVisitor<'a>
+impl<'a, 'b> StatementVisitor<'b> for ReturnStatementVisitor<'a>
 where
     'b: 'a,
 {
@@ -832,18 +831,18 @@ where
                 // Don't recurse.
             }
             StmtKind::Return { value } => self.returns.push(value.as_deref()),
-            _ => visitor::walk_stmt(self, stmt),
+            _ => walk_stmt(self, stmt),
         }
     }
 }
 
-/// A [`Visitor`] that collects all `raise` statements in a function or method.
+/// A [`StatementVisitor`] that collects all `raise` statements in a function or method.
 #[derive(Default)]
 pub struct RaiseStatementVisitor<'a> {
     pub raises: Vec<(TextRange, Option<&'a Expr>, Option<&'a Expr>)>,
 }
 
-impl<'a, 'b> Visitor<'b> for RaiseStatementVisitor<'b>
+impl<'a, 'b> StatementVisitor<'b> for RaiseStatementVisitor<'b>
 where
     'b: 'a,
 {
@@ -859,19 +858,19 @@ where
             | StmtKind::Try { .. }
             | StmtKind::TryStar { .. } => {}
             StmtKind::If { body, orelse, .. } => {
-                visitor::walk_body(self, body);
+                walk_body(self, body);
-                visitor::walk_body(self, orelse);
+                walk_body(self, orelse);
             }
             StmtKind::While { body, .. }
             | StmtKind::With { body, .. }
             | StmtKind::AsyncWith { body, .. }
             | StmtKind::For { body, .. }
             | StmtKind::AsyncFor { body, .. } => {
-                visitor::walk_body(self, body);
+                walk_body(self, body);
             }
             StmtKind::Match { cases, .. } => {
                 for case in cases {
-                    visitor::walk_body(self, &case.body);
+                    walk_body(self, &case.body);
                 }
             }
             _ => {}
@@ -884,7 +883,7 @@ struct GlobalStatementVisitor<'a> {
     globals: FxHashMap<&'a str, &'a Stmt>,
 }
 
-impl<'a> Visitor<'a> for GlobalStatementVisitor<'a> {
+impl<'a> StatementVisitor<'a> for GlobalStatementVisitor<'a> {
     fn visit_stmt(&mut self, stmt: &'a Stmt) {
         match &stmt.node {
             StmtKind::Global { names } => {
@@ -897,7 +896,7 @@ impl<'a> Visitor<'a> for GlobalStatementVisitor<'a> {
             | StmtKind::ClassDef { .. } => {
                 // Don't recurse.
             }
-            _ => visitor::walk_stmt(self, stmt),
+            _ => walk_stmt(self, stmt),
         }
     }
 }

crates/ruff_python_ast/src/lib.rs

@@ -8,6 +8,7 @@ pub mod imports;
 pub mod newlines;
 pub mod relocate;
 pub mod source_code;
+pub mod statement_visitor;
 pub mod str;
 pub mod token_kind;
 pub mod types;

crates/ruff_python_ast/src/statement_visitor.rs

@@ -0,0 +1,111 @@
+//! Specialized AST visitor trait and walk functions that only visit statements.
+
+use rustpython_parser::ast::{Excepthandler, ExcepthandlerKind, MatchCase, Stmt, StmtKind};
+
+/// A trait for AST visitors that only need to visit statements.
+pub trait StatementVisitor<'a> {
+    fn visit_body(&mut self, body: &'a [Stmt]) {
+        walk_body(self, body);
+    }
+    fn visit_stmt(&mut self, stmt: &'a Stmt) {
+        walk_stmt(self, stmt);
+    }
+    fn visit_excepthandler(&mut self, excepthandler: &'a Excepthandler) {
+        walk_excepthandler(self, excepthandler);
+    }
+    fn visit_match_case(&mut self, match_case: &'a MatchCase) {
+        walk_match_case(self, match_case);
+    }
+}
+
+pub fn walk_body<'a, V: StatementVisitor<'a> + ?Sized>(visitor: &mut V, body: &'a [Stmt]) {
+    for stmt in body {
+        visitor.visit_stmt(stmt);
+    }
+}
+
+pub fn walk_stmt<'a, V: StatementVisitor<'a> + ?Sized>(visitor: &mut V, stmt: &'a Stmt) {
+    match &stmt.node {
+        StmtKind::FunctionDef { body, .. } => {
+            visitor.visit_body(body);
+        }
+        StmtKind::AsyncFunctionDef { body, .. } => {
+            visitor.visit_body(body);
+        }
+        StmtKind::For { body, orelse, .. } => {
+            visitor.visit_body(body);
+            visitor.visit_body(orelse);
+        }
+        StmtKind::ClassDef { body, .. } => {
+            visitor.visit_body(body);
+        }
+        StmtKind::AsyncFor { body, orelse, .. } => {
+            visitor.visit_body(body);
+            visitor.visit_body(orelse);
+        }
+        StmtKind::While { body, orelse, .. } => {
+            visitor.visit_body(body);
+            visitor.visit_body(orelse);
+        }
+        StmtKind::If { body, orelse, .. } => {
+            visitor.visit_body(body);
+            visitor.visit_body(orelse);
+        }
+        StmtKind::With { body, .. } => {
+            visitor.visit_body(body);
+        }
+        StmtKind::AsyncWith { body, .. } => {
+            visitor.visit_body(body);
+        }
+        StmtKind::Match { cases, .. } => {
+            for match_case in cases {
+                visitor.visit_match_case(match_case);
+            }
+        }
+        StmtKind::Try {
+            body,
+            handlers,
+            orelse,
+            finalbody,
+        } => {
+            visitor.visit_body(body);
+            for excepthandler in handlers {
+                visitor.visit_excepthandler(excepthandler);
+            }
+            visitor.visit_body(orelse);
+            visitor.visit_body(finalbody);
+        }
+        StmtKind::TryStar {
+            body,
+            handlers,
+            orelse,
+            finalbody,
+        } => {
+            visitor.visit_body(body);
+            for excepthandler in handlers {
+                visitor.visit_excepthandler(excepthandler);
+            }
+            visitor.visit_body(orelse);
+            visitor.visit_body(finalbody);
+        }
+        _ => {}
+    }
+}
+
+pub fn walk_excepthandler<'a, V: StatementVisitor<'a> + ?Sized>(
+    visitor: &mut V,
+    excepthandler: &'a Excepthandler,
+) {
+    match &excepthandler.node {
+        ExcepthandlerKind::ExceptHandler { body, .. } => {
+            visitor.visit_body(body);
+        }
+    }
+}
+
+pub fn walk_match_case<'a, V: StatementVisitor<'a> + ?Sized>(
+    visitor: &mut V,
+    match_case: &'a MatchCase,
+) {
+    visitor.visit_body(&match_case.body);
+}

crates/ruff_python_ast/src/visitor.rs

@@ -1,9 +1,15 @@
+//! AST visitor trait and walk functions.
+
 use rustpython_parser::ast::{
     Alias, Arg, Arguments, Boolop, Cmpop, Comprehension, Constant, Excepthandler,
     ExcepthandlerKind, Expr, ExprContext, ExprKind, Keyword, MatchCase, Operator, Pattern,
     PatternKind, Stmt, StmtKind, Unaryop, Withitem,
 };
 
+/// A trait for AST visitors. Visits all nodes in the AST recursively.
+///
+/// Prefer [`crate::statement_visitor::StatementVisitor`] for visitors that only need to visit
+/// statements.
 pub trait Visitor<'a> {
     fn visit_stmt(&mut self, stmt: &'a Stmt) {
         walk_stmt(self, stmt);