From 38a385fb6f8af98c7a2407c643cb241d823ea200 Mon Sep 17 00:00:00 2001
From: Dhruv Manilawala <dhruvmanila@gmail.com>
Date: Mon, 18 Nov 2024 12:33:19 +0530
Subject: [PATCH] Simplify quote annotator logic for list expression (#14425)

## Summary

Follow-up to #14371, this PR simplifies the visitor logic for list
expressions to remove the state management. We just need to make sure
that we visit the nested expressions using the `QuoteAnnotator` and not
the `Generator`. This is similar to what's being done for binary
expressions.

As per the
[grammar](https://typing.readthedocs.io/en/latest/spec/annotations.html#grammar-token-expression-grammar-annotation_expression),
list expressions can be present which can contain other type expressions
(`Callable`):
```
       | <Callable> '[' <Concatenate> '[' (type_expression ',')+
                    (name | '...') ']' ',' type_expression ']'
             (where name must be a valid in-scope ParamSpec)
       | <Callable> '[' '[' maybe_unpacked (',' maybe_unpacked)*
                    ']' ',' type_expression ']'
```

## Test Plan

`cargo insta test`
---
 .../src/rules/flake8_type_checking/helpers.rs | 20 +++++++++----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/crates/ruff_linter/src/rules/flake8_type_checking/helpers.rs b/crates/ruff_linter/src/rules/flake8_type_checking/helpers.rs
index 6793becbd1..7da64c8bf7 100644
--- a/crates/ruff_linter/src/rules/flake8_type_checking/helpers.rs
+++ b/crates/ruff_linter/src/rules/flake8_type_checking/helpers.rs
@@ -392,23 +392,21 @@ impl<'a> SourceOrderVisitor<'a> for QuoteAnnotator<'a> {
                 }
                 self.state.pop();
             }
+            // For the following expressions, we just need to make sure to visit the nested
+            // expressions using the quote annotator and not use the generator. This is so that any
+            // subscript elements nested within them are identified and quoted correctly.
             Expr::List(ast::ExprList { elts, .. }) => {
-                let Some((first, remaining)) = elts.split_first() else {
-                    return;
-                };
+                let mut first = true;
                 self.annotation.push('[');
-                self.visit_expr(first);
-                if let Some(last) = self.state.last_mut() {
-                    if *last == QuoteAnnotatorState::AnnotatedFirst {
-                        *last = QuoteAnnotatorState::AnnotatedRest;
+                for expr in elts {
+                    if first {
+                        first = false;
+                    } else {
+                        self.annotation.push_str(", ");
                     }
-                }
-                for expr in remaining {
-                    self.annotation.push_str(", ");
                     self.visit_expr(expr);
                 }
                 self.annotation.push(']');
-                self.state.pop();
             }
             Expr::BinOp(ast::ExprBinOp {
                 left, op, right, ..