Expand F841 fixes to handle parenthesized targets (#7110)

crates/ruff/resources/test/fixtures/pyflakes/F841_3.py

@@ -165,3 +165,9 @@ def f():
     x = 1
 
     y = 2
+
+
+def f():
+    (x) = foo()
+    ((x)) = foo()
+    (x) = (y.z) = foo()

crates/ruff/src/rules/pyflakes/rules/unused_variable.rs

@@ -3,6 +3,7 @@ use itertools::Itertools;
 use ruff_diagnostics::{AutofixKind, Diagnostic, Edit, Fix, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::contains_effect;
+use ruff_python_ast::parenthesize::parenthesized_range;
 use ruff_python_ast::{self as ast, PySourceType, Stmt};
 use ruff_python_parser::{lexer, AsMode, Tok};
 use ruff_python_semantic::{Binding, Scope};
@@ -220,11 +221,19 @@ fn remove_unused_variable(binding: &Binding, checker: &Checker) -> Option<Fix> {
                 {
                     // If the expression is complex (`x = foo()`), remove the assignment,
                     // but preserve the right-hand side.
-                    let start = target.start();
+                    let start = parenthesized_range(
-                    let end =
+                        target.into(),
-                        match_token_after(start, checker.locator(), checker.source_type, |tok| {
+                        statement.into(),
-                            tok == Tok::Equal
+                        checker.locator().contents(),
-                        })?
+                    )
+                    .unwrap_or(target.range())
+                    .start();
+                    let end = match_token_after(
+                        target.end(),
+                        checker.locator(),
+                        checker.source_type,
+                        |tok| tok == Tok::Equal,
+                    )?
                     .start();
                     let edit = Edit::deletion(start, end);
                     Some(Fix::suggested(edit))

crates/ruff/src/rules/pyflakes/snapshots/ruff__rules__pyflakes__tests__F841_F841_3.py.snap

@@ -657,6 +657,7 @@ F841_3.py:165:5: F841 [*] Local variable `x` is assigned to but never used
 165     |-    x = 1
 166 165 | 
 167 166 |     y = 2
+168 167 | 
 
 F841_3.py:167:5: F841 [*] Local variable `y` is assigned to but never used
     |
@@ -672,5 +673,24 @@ F841_3.py:167:5: F841 [*] Local variable `y` is assigned to but never used
 165 165 |     x = 1
 166 166 | 
 167     |-    y = 2
+168 167 | 
+169 168 | 
+170 169 | def f():
+
+F841_3.py:173:6: F841 [*] Local variable `x` is assigned to but never used
+    |
+171 |     (x) = foo()
+172 |     ((x)) = foo()
+173 |     (x) = (y.z) = foo()
+    |      ^ F841
+    |
+    = help: Remove assignment to unused variable `x`
+
+ℹ Suggested fix
+170 170 | def f():
+171 171 |     (x) = foo()
+172 172 |     ((x)) = foo()
+173     |-    (x) = (y.z) = foo()
+    173 |+    (y.z) = foo()