F841: Stabalize unpacking support

Closes https://github.com/astral-sh/ruff/issues/12110.

crates/ruff/tests/snapshots/show_settings__display_default_settings.snap

@@ -260,6 +260,7 @@ linter.flake8_import_conventions.aliases = {
 	seaborn = sns,
 	tensorflow = tf,
 	tkinter = tk,
+	xml.etree.ElementTree = ET,
 }
 linter.flake8_import_conventions.banned_aliases = {}
 linter.flake8_import_conventions.banned_from = []

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1498,7 +1498,9 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             }
 
             if checker.enabled(Rule::UnnecessaryDictComprehensionForIterable) {
-                ruff::rules::unnecessary_dict_comprehension_for_iterable(checker, dict_comp);
+                flake8_comprehensions::rules::unnecessary_dict_comprehension_for_iterable(
+                    checker, dict_comp,
+                );
             }
 
             if checker.enabled(Rule::FunctionUsesLoopVariable) {

crates/ruff_linter/src/codes.rs

@@ -4,12 +4,12 @@
 /// `--select`. For pylint this is e.g. C0414 and E0118 but also C and E01.
 use std::fmt::Formatter;
 
+use strum_macros::{AsRefStr, EnumIter};
+
 use crate::registry::{AsRule, Linter};
 use crate::rule_selector::is_single_rule_selector;
 use crate::rules;
 
-use strum_macros::{AsRefStr, EnumIter};
-
 #[derive(PartialEq, Eq, PartialOrd, Ord)]
 pub struct NoqaCode(&'static str, &'static str);
 
@@ -378,6 +378,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8Comprehensions, "17") => (RuleGroup::Stable, rules::flake8_comprehensions::rules::UnnecessaryMap),
         (Flake8Comprehensions, "18") => (RuleGroup::Stable, rules::flake8_comprehensions::rules::UnnecessaryLiteralWithinDictCall),
         (Flake8Comprehensions, "19") => (RuleGroup::Stable, rules::flake8_comprehensions::rules::UnnecessaryComprehensionInCall),
+        (Flake8Comprehensions, "20") => (RuleGroup::Preview, rules::flake8_comprehensions::rules::UnnecessaryDictComprehensionForIterable),
 
         // flake8-debugger
         (Flake8Debugger, "0") => (RuleGroup::Stable, rules::flake8_debugger::rules::Debugger),
@@ -951,7 +952,6 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Ruff, "022") => (RuleGroup::Preview, rules::ruff::rules::UnsortedDunderAll),
         (Ruff, "023") => (RuleGroup::Preview, rules::ruff::rules::UnsortedDunderSlots),
         (Ruff, "024") => (RuleGroup::Stable, rules::ruff::rules::MutableFromkeysValue),
-        (Ruff, "025") => (RuleGroup::Preview, rules::ruff::rules::UnnecessaryDictComprehensionForIterable),
         (Ruff, "026") => (RuleGroup::Stable, rules::ruff::rules::DefaultFactoryKwarg),
         (Ruff, "027") => (RuleGroup::Preview, rules::ruff::rules::MissingFStringSyntax),
         (Ruff, "028") => (RuleGroup::Preview, rules::ruff::rules::InvalidFormatterSuppressionComment),

crates/ruff_linter/src/rule_redirects.rs

@@ -123,5 +123,7 @@ static REDIRECTS: Lazy<HashMap<&'static str, &'static str>> = Lazy::new(|| {
         ("RUF96", "RUF95"),
         // See: https://github.com/astral-sh/ruff/issues/10791
         ("PLW0117", "PLW0177"),
+        // See: https://github.com/astral-sh/ruff/issues/12110
+        ("RUF025", "C420"),
     ])
 });

crates/ruff_linter/src/rules/flake8_comprehensions/mod.rs

@@ -21,6 +21,7 @@ mod tests {
     #[test_case(Rule::UnnecessaryComprehension, Path::new("C416.py"))]
     #[test_case(Rule::UnnecessaryComprehensionInCall, Path::new("C419.py"))]
     #[test_case(Rule::UnnecessaryComprehensionInCall, Path::new("C419_2.py"))]
+    #[test_case(Rule::UnnecessaryDictComprehensionForIterable, Path::new("C420.py"))]
     #[test_case(Rule::UnnecessaryDoubleCastOrProcess, Path::new("C414.py"))]
     #[test_case(Rule::UnnecessaryGeneratorDict, Path::new("C402.py"))]
     #[test_case(Rule::UnnecessaryGeneratorList, Path::new("C400.py"))]

crates/ruff_linter/src/rules/flake8_comprehensions/rules/mod.rs

@@ -2,6 +2,7 @@ pub(crate) use unnecessary_call_around_sorted::*;
 pub(crate) use unnecessary_collection_call::*;
 pub(crate) use unnecessary_comprehension::*;
 pub(crate) use unnecessary_comprehension_in_call::*;
+pub(crate) use unnecessary_dict_comprehension_for_iterable::*;
 pub(crate) use unnecessary_double_cast_or_process::*;
 pub(crate) use unnecessary_generator_dict::*;
 pub(crate) use unnecessary_generator_list::*;
@@ -22,6 +23,7 @@ mod unnecessary_call_around_sorted;
 mod unnecessary_collection_call;
 mod unnecessary_comprehension;
 mod unnecessary_comprehension_in_call;
+mod unnecessary_dict_comprehension_for_iterable;
 mod unnecessary_double_cast_or_process;
 mod unnecessary_generator_dict;
 mod unnecessary_generator_list;

crates/ruff_linter/src/rules/flake8_comprehensions/snapshots/ruff_linter__rules__flake8_comprehensions__tests__C420_C420.py.snap

@@ -1,12 +1,12 @@
 ---
-source: crates/ruff_linter/src/rules/ruff/mod.rs
+source: crates/ruff_linter/src/rules/flake8_comprehensions/mod.rs
 ---
-RUF025.py:6:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:6:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
   |
 4 | def func():
 5 |     numbers = [1, 2, 3]
 6 |     {n: None for n in numbers}  # RUF025
-  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
   |
   = help: Replace with `dict.fromkeys(iterable, value)`)
 
@@ -20,11 +20,11 @@ RUF025.py:6:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict
 8 8 | 
 9 9 | def func():
 
-RUF025.py:10:23: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:10:23: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
  9 | def func():
 10 |     for key, value in {n: 1 for n in [1, 2, 3]}.items():  # RUF025
-   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^ C420
 11 |         pass
    |
    = help: Replace with `dict.fromkeys(iterable)`)
@@ -39,11 +39,11 @@ RUF025.py:10:23: RUF025 [*] Unnecessary dict comprehension for iterable; use `di
 12 12 | 
 13 13 | 
 
-RUF025.py:15:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:15:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 14 | def func():
 15 |     {n: 1.1 for n in [1, 2, 3]}  # RUF025
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -57,12 +57,12 @@ RUF025.py:15:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 17 17 | 
 18 18 | def func():
 
-RUF025.py:26:7: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:26:7: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 24 |         return data
 25 | 
 26 |     f({c: "a" for c in "12345"})  # RUF025
-   |       ^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |       ^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -76,11 +76,11 @@ RUF025.py:26:7: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 28 28 | 
 29 29 | def func():
 
-RUF025.py:30:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:30:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 29 | def func():
 30 |     {n: True for n in [1, 2, 2]}  # RUF025
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -94,11 +94,11 @@ RUF025.py:30:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 32 32 | 
 33 33 | def func():
 
-RUF025.py:34:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:34:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 33 | def func():
 34 |     {n: b"hello" for n in (1, 2, 2)}  # RUF025
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -112,11 +112,11 @@ RUF025.py:34:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 36 36 | 
 37 37 | def func():
 
-RUF025.py:38:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:38:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 37 | def func():
 38 |     {n: ... for n in [1, 2, 3]}  # RUF025
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -130,11 +130,11 @@ RUF025.py:38:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 40 40 | 
 41 41 | def func():
 
-RUF025.py:42:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:42:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 41 | def func():
 42 |     {n: False for n in {1: "a", 2: "b"}}  # RUF025
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -148,11 +148,11 @@ RUF025.py:42:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 44 44 | 
 45 45 | def func():
 
-RUF025.py:46:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:46:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 45 | def func():
 46 |     {(a, b): 1 for (a, b) in [(1, 2), (3, 4)]}  # RUF025
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -166,11 +166,11 @@ RUF025.py:46:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 48 48 | 
 49 49 | def func():
 
-RUF025.py:54:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:54:5: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 53 |     a = f()
 54 |     {n: a for n in [1, 2, 3]}  # RUF025
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -184,12 +184,12 @@ RUF025.py:54:5: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 56 56 | 
 57 57 | def func():
 
-RUF025.py:59:6: RUF025 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
+C420.py:59:6: C420 [*] Unnecessary dict comprehension for iterable; use `dict.fromkeys` instead
    |
 57 | def func():
 58 |     values = ["a", "b", "c"]
 59 |     [{n: values for n in [1, 2, 3]}]  # RUF025
-   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ RUF025
+   |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C420
    |
    = help: Replace with `dict.fromkeys(iterable)`)
 
@@ -202,5 +202,3 @@ RUF025.py:59:6: RUF025 [*] Unnecessary dict comprehension for iterable; use `dic
 60 60 | 
 61 61 | 
 62 62 | # Non-violation cases: RUF025
-
-

crates/ruff_linter/src/rules/flake8_import_conventions/settings.rs

@@ -24,6 +24,7 @@ const CONVENTIONAL_ALIASES: &[(&str, &str)] = &[
     ("plotly.express", "px"),
     ("polars", "pl"),
     ("pyarrow", "pa"),
+    ("xml.etree.ElementTree", "ET"),
 ];
 
 #[derive(Debug, Default, Clone, PartialEq, Eq, Serialize, Deserialize, CacheKey)]

crates/ruff_linter/src/rules/pyflakes/mod.rs

@@ -208,7 +208,6 @@ mod tests {
         Ok(())
     }
 
-    #[test_case(Rule::UnusedVariable, Path::new("F841_4.py"))]
     #[test_case(Rule::UnusedImport, Path::new("__init__.py"))]
     #[test_case(Rule::UnusedImport, Path::new("F401_24/__init__.py"))]
     #[test_case(Rule::UnusedImport, Path::new("F401_25__all_nonempty/__init__.py"))]
@@ -1285,33 +1284,6 @@ mod tests {
         );
     }
 
-    #[test]
-    fn used_as_star_unpack() {
-        // In stable, starred names in unpack are used if RHS is not a tuple/list literal.
-        // In preview, these should be marked as unused.
-        flakes(
-            r"
-        def f():
-            a, *b = range(10)
-        ",
-            &[],
-        );
-        flakes(
-            r"
-        def f():
-            (*a, b) = range(10)
-        ",
-            &[],
-        );
-        flakes(
-            r"
-        def f():
-            [a, *b, c] = range(10)
-        ",
-            &[],
-        );
-    }
-
     #[test]
     fn keyword_only_args() {
         // Keyword-only arg names are defined.

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

@@ -261,7 +261,6 @@ pub(crate) fn unused_variable(checker: &Checker, scope: &Scope, diagnostics: &mu
             if (binding.kind.is_assignment()
                 || binding.kind.is_named_expr_assignment()
                 || binding.kind.is_with_item_var())
-                && (!binding.is_unpacked_assignment() || checker.settings.preview.is_enabled())
                 && binding.is_unused()
                 && !binding.is_nonlocal()
                 && !binding.is_global()

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_0.py.snap

@@ -99,6 +99,84 @@ F841_0.py:21:9: F841 [*] Local variable `b` is assigned to but never used
 23 23 |     bar = (1, 2)
 24 24 |     (c, d) = bar
 
+F841_0.py:24:6: F841 [*] Local variable `c` is assigned to but never used
+   |
+23 |     bar = (1, 2)
+24 |     (c, d) = bar
+   |      ^ F841
+25 | 
+26 |     (x, y) = baz = bar
+   |
+   = help: Remove assignment to unused variable `c`
+
+ℹ Unsafe fix
+21 21 |     (a, b) = (1, 2)
+22 22 | 
+23 23 |     bar = (1, 2)
+24    |-    (c, d) = bar
+   24 |+    (_c, d) = bar
+25 25 | 
+26 26 |     (x, y) = baz = bar
+27 27 | 
+
+F841_0.py:24:9: F841 [*] Local variable `d` is assigned to but never used
+   |
+23 |     bar = (1, 2)
+24 |     (c, d) = bar
+   |         ^ F841
+25 | 
+26 |     (x, y) = baz = bar
+   |
+   = help: Remove assignment to unused variable `d`
+
+ℹ Unsafe fix
+21 21 |     (a, b) = (1, 2)
+22 22 | 
+23 23 |     bar = (1, 2)
+24    |-    (c, d) = bar
+   24 |+    (c, _d) = bar
+25 25 | 
+26 26 |     (x, y) = baz = bar
+27 27 | 
+
+F841_0.py:26:6: F841 [*] Local variable `x` is assigned to but never used
+   |
+24 |     (c, d) = bar
+25 | 
+26 |     (x, y) = baz = bar
+   |      ^ F841
+   |
+   = help: Remove assignment to unused variable `x`
+
+ℹ Unsafe fix
+23 23 |     bar = (1, 2)
+24 24 |     (c, d) = bar
+25 25 | 
+26    |-    (x, y) = baz = bar
+   26 |+    (_x, y) = baz = bar
+27 27 | 
+28 28 | 
+29 29 | def f():
+
+F841_0.py:26:9: F841 [*] Local variable `y` is assigned to but never used
+   |
+24 |     (c, d) = bar
+25 | 
+26 |     (x, y) = baz = bar
+   |         ^ F841
+   |
+   = help: Remove assignment to unused variable `y`
+
+ℹ Unsafe fix
+23 23 |     bar = (1, 2)
+24 24 |     (c, d) = bar
+25 25 | 
+26    |-    (x, y) = baz = bar
+   26 |+    (x, _y) = baz = bar
+27 27 | 
+28 28 | 
+29 29 | def f():
+
 F841_0.py:26:14: F841 [*] Local variable `baz` is assigned to but never used
    |
 24 |     (c, d) = bar
@@ -139,6 +217,26 @@ F841_0.py:51:9: F841 [*] Local variable `b` is assigned to but never used
 53 53 |     def d():
 54 54 |         nonlocal b
 
+F841_0.py:66:24: F841 Local variable `connection` is assigned to but never used
+   |
+64 |         return None, None
+65 | 
+66 |     with connect() as (connection, cursor):
+   |                        ^^^^^^^^^^ F841
+67 |         cursor.execute("SELECT * FROM users")
+   |
+   = help: Remove assignment to unused variable `connection`
+
+F841_0.py:74:24: F841 Local variable `connection` is assigned to but never used
+   |
+72 |         return None, None
+73 | 
+74 |     with connect() as (connection, cursor):
+   |                        ^^^^^^^^^^ F841
+75 |         cursor.execute("SELECT * FROM users")
+   |
+   = help: Remove assignment to unused variable `connection`
+
 F841_0.py:79:26: F841 [*] Local variable `my_file` is assigned to but never used
    |
 78 | def f():
@@ -158,6 +256,24 @@ F841_0.py:79:26: F841 [*] Local variable `my_file` is assigned to but never used
 81 81 | 
 82 82 | 
 
+F841_0.py:79:49: F841 Local variable `this` is assigned to but never used
+   |
+78 | def f():
+79 |     with open("file") as my_file, open("") as ((this, that)):
+   |                                                 ^^^^ F841
+80 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `this`
+
+F841_0.py:79:55: F841 Local variable `that` is assigned to but never used
+   |
+78 | def f():
+79 |     with open("file") as my_file, open("") as ((this, that)):
+   |                                                       ^^^^ F841
+80 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `that`
+
 F841_0.py:85:25: F841 [*] Local variable `my_file` is assigned to but never used
    |
 83 | def f():
@@ -179,6 +295,28 @@ F841_0.py:85:25: F841 [*] Local variable `my_file` is assigned to but never used
 87 87 |     ):
 88 88 |         print("hello")
 
+F841_0.py:86:23: F841 Local variable `this` is assigned to but never used
+   |
+84 |     with (
+85 |         open("file") as my_file,
+86 |         open("") as ((this, that)),
+   |                       ^^^^ F841
+87 |     ):
+88 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `this`
+
+F841_0.py:86:29: F841 Local variable `that` is assigned to but never used
+   |
+84 |     with (
+85 |         open("file") as my_file,
+86 |         open("") as ((this, that)),
+   |                             ^^^^ F841
+87 |     ):
+88 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `that`
+
 F841_0.py:102:5: F841 [*] Local variable `msg3` is assigned to but never used
     |
 100 |     msg1 = "Hello, world!"
@@ -238,5 +376,3 @@ F841_0.py:127:21: F841 Local variable `value` is assigned to but never used
 128 |         print(key)
     |
     = help: Remove assignment to unused variable `value`
-
-

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_1.py.snap

@@ -1,6 +1,38 @@
 ---
 source: crates/ruff_linter/src/rules/pyflakes/mod.rs
 ---
+F841_1.py:2:5: F841 [*] Local variable `x` is assigned to but never used
+  |
+1 | def f(tup):
+2 |     x, y = tup
+  |     ^ F841
+  |
+  = help: Remove assignment to unused variable `x`
+
+ℹ Unsafe fix
+1 1 | def f(tup):
+2   |-    x, y = tup
+  2 |+    _x, y = tup
+3 3 | 
+4 4 | 
+5 5 | def f():
+
+F841_1.py:2:8: F841 [*] Local variable `y` is assigned to but never used
+  |
+1 | def f(tup):
+2 |     x, y = tup
+  |        ^ F841
+  |
+  = help: Remove assignment to unused variable `y`
+
+ℹ Unsafe fix
+1 1 | def f(tup):
+2   |-    x, y = tup
+  2 |+    x, _y = tup
+3 3 | 
+4 4 | 
+5 5 | def f():
+
 F841_1.py:6:5: F841 [*] Local variable `x` is assigned to but never used
   |
 5 | def f():
@@ -37,6 +69,62 @@ F841_1.py:6:8: F841 [*] Local variable `y` is assigned to but never used
 8 8 | 
 9 9 | def f():
 
+F841_1.py:10:9: F841 [*] Local variable `y` is assigned to but never used
+   |
+ 9 | def f():
+10 |     (x, y) = coords = 1, 2
+   |         ^ F841
+11 |     if x > 1:
+12 |         print(coords)
+   |
+   = help: Remove assignment to unused variable `y`
+
+ℹ Unsafe fix
+7  7  | 
+8  8  | 
+9  9  | def f():
+10    |-    (x, y) = coords = 1, 2
+   10 |+    (x, _y) = coords = 1, 2
+11 11 |     if x > 1:
+12 12 |         print(coords)
+13 13 | 
+
+F841_1.py:16:6: F841 [*] Local variable `x` is assigned to but never used
+   |
+15 | def f():
+16 |     (x, y) = coords = 1, 2
+   |      ^ F841
+   |
+   = help: Remove assignment to unused variable `x`
+
+ℹ Unsafe fix
+13 13 | 
+14 14 | 
+15 15 | def f():
+16    |-    (x, y) = coords = 1, 2
+   16 |+    (_x, y) = coords = 1, 2
+17 17 | 
+18 18 | 
+19 19 | def f():
+
+F841_1.py:16:9: F841 [*] Local variable `y` is assigned to but never used
+   |
+15 | def f():
+16 |     (x, y) = coords = 1, 2
+   |         ^ F841
+   |
+   = help: Remove assignment to unused variable `y`
+
+ℹ Unsafe fix
+13 13 | 
+14 14 | 
+15 15 | def f():
+16    |-    (x, y) = coords = 1, 2
+   16 |+    (x, _y) = coords = 1, 2
+17 17 | 
+18 18 | 
+19 19 | def f():
+
 F841_1.py:16:14: F841 [*] Local variable `coords` is assigned to but never used
    |
 15 | def f():
@@ -73,6 +161,42 @@ F841_1.py:20:5: F841 [*] Local variable `coords` is assigned to but never used
 22 22 | 
 23 23 | def f():
 
+F841_1.py:20:15: F841 [*] Local variable `x` is assigned to but never used
+   |
+19 | def f():
+20 |     coords = (x, y) = 1, 2
+   |               ^ F841
+   |
+   = help: Remove assignment to unused variable `x`
+
+ℹ Unsafe fix
+17 17 | 
+18 18 | 
+19 19 | def f():
+20    |-    coords = (x, y) = 1, 2
+   20 |+    coords = (_x, y) = 1, 2
+21 21 | 
+22 22 | 
+23 23 | def f():
+
+F841_1.py:20:18: F841 [*] Local variable `y` is assigned to but never used
+   |
+19 | def f():
+20 |     coords = (x, y) = 1, 2
+   |                  ^ F841
+   |
+   = help: Remove assignment to unused variable `y`
+
+ℹ Unsafe fix
+17 17 | 
+18 18 | 
+19 19 | def f():
+20    |-    coords = (x, y) = 1, 2
+   20 |+    coords = (x, _y) = 1, 2
+21 21 | 
+22 22 | 
+23 23 | def f():
+
 F841_1.py:24:6: F841 [*] Local variable `a` is assigned to but never used
    |
 23 | def f():
@@ -132,5 +256,3 @@ F841_1.py:24:18: F841 [*] Local variable `y` is assigned to but never used
 23 23 | def f():
 24    |-    (a, b) = (x, y) = 1, 2  # this triggers F841 on everything
    24 |+    (a, b) = (x, _y) = 1, 2  # this triggers F841 on everything
-
-

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_3.py.snap

@@ -96,6 +96,26 @@ F841_3.py:21:19: F841 [*] Local variable `x1` is assigned to but never used
 23 23 | 
 24 24 |     with foo() as (x2, y2):
 
+F841_3.py:24:20: F841 Local variable `x2` is assigned to but never used
+   |
+22 |         pass
+23 | 
+24 |     with foo() as (x2, y2):
+   |                    ^^ F841
+25 |         pass
+   |
+   = help: Remove assignment to unused variable `x2`
+
+F841_3.py:24:24: F841 Local variable `y2` is assigned to but never used
+   |
+22 |         pass
+23 | 
+24 |     with foo() as (x2, y2):
+   |                        ^^ F841
+25 |         pass
+   |
+   = help: Remove assignment to unused variable `y2`
+
 F841_3.py:27:20: F841 [*] Local variable `x3` is assigned to but never used
    |
 25 |         pass
@@ -196,6 +216,46 @@ F841_3.py:32:10: F841 [*] Local variable `y1` is assigned to but never used
 34 34 |     coords3 = (x3, y3) = (1, 2)
 35 35 | 
 
+F841_3.py:33:6: F841 [*] Local variable `x2` is assigned to but never used
+   |
+31 | def f():
+32 |     (x1, y1) = (1, 2)
+33 |     (x2, y2) = coords2 = (1, 2)
+   |      ^^ F841
+34 |     coords3 = (x3, y3) = (1, 2)
+   |
+   = help: Remove assignment to unused variable `x2`
+
+ℹ Unsafe fix
+30 30 | 
+31 31 | def f():
+32 32 |     (x1, y1) = (1, 2)
+33    |-    (x2, y2) = coords2 = (1, 2)
+   33 |+    (_x2, y2) = coords2 = (1, 2)
+34 34 |     coords3 = (x3, y3) = (1, 2)
+35 35 | 
+36 36 | 
+
+F841_3.py:33:10: F841 [*] Local variable `y2` is assigned to but never used
+   |
+31 | def f():
+32 |     (x1, y1) = (1, 2)
+33 |     (x2, y2) = coords2 = (1, 2)
+   |          ^^ F841
+34 |     coords3 = (x3, y3) = (1, 2)
+   |
+   = help: Remove assignment to unused variable `y2`
+
+ℹ Unsafe fix
+30 30 | 
+31 31 | def f():
+32 32 |     (x1, y1) = (1, 2)
+33    |-    (x2, y2) = coords2 = (1, 2)
+   33 |+    (x2, _y2) = coords2 = (1, 2)
+34 34 |     coords3 = (x3, y3) = (1, 2)
+35 35 | 
+36 36 | 
+
 F841_3.py:33:16: F841 [*] Local variable `coords2` is assigned to but never used
    |
 31 | def f():
@@ -235,6 +295,44 @@ F841_3.py:34:5: F841 [*] Local variable `coords3` is assigned to but never used
 36 36 | 
 37 37 | def f():
 
+F841_3.py:34:16: F841 [*] Local variable `x3` is assigned to but never used
+   |
+32 |     (x1, y1) = (1, 2)
+33 |     (x2, y2) = coords2 = (1, 2)
+34 |     coords3 = (x3, y3) = (1, 2)
+   |                ^^ F841
+   |
+   = help: Remove assignment to unused variable `x3`
+
+ℹ Unsafe fix
+31 31 | def f():
+32 32 |     (x1, y1) = (1, 2)
+33 33 |     (x2, y2) = coords2 = (1, 2)
+34    |-    coords3 = (x3, y3) = (1, 2)
+   34 |+    coords3 = (_x3, y3) = (1, 2)
+35 35 | 
+36 36 | 
+37 37 | def f():
+
+F841_3.py:34:20: F841 [*] Local variable `y3` is assigned to but never used
+   |
+32 |     (x1, y1) = (1, 2)
+33 |     (x2, y2) = coords2 = (1, 2)
+34 |     coords3 = (x3, y3) = (1, 2)
+   |                    ^^ F841
+   |
+   = help: Remove assignment to unused variable `y3`
+
+ℹ Unsafe fix
+31 31 | def f():
+32 32 |     (x1, y1) = (1, 2)
+33 33 |     (x2, y2) = coords2 = (1, 2)
+34    |-    coords3 = (x3, y3) = (1, 2)
+   34 |+    coords3 = (x3, _y3) = (1, 2)
+35 35 | 
+36 36 | 
+37 37 | def f():
+
 F841_3.py:40:26: F841 [*] Local variable `x1` is assigned to but never used
    |
 38 |     try:
@@ -397,6 +495,24 @@ F841_3.py:77:25: F841 [*] Local variable `cm` is assigned to but never used
 79 79 | 
 80 80 | 
 
+F841_3.py:82:24: F841 Local variable `x` is assigned to but never used
+   |
+81 | def f():
+82 |     with Nested(m) as (x, y):
+   |                        ^ F841
+83 |         pass
+   |
+   = help: Remove assignment to unused variable `x`
+
+F841_3.py:82:27: F841 Local variable `y` is assigned to but never used
+   |
+81 | def f():
+82 |     with Nested(m) as (x, y):
+   |                           ^ F841
+83 |         pass
+   |
+   = help: Remove assignment to unused variable `y`
+
 F841_3.py:87:26: F841 [*] Local variable `cm` is assigned to but never used
    |
 86 | def f():
@@ -490,6 +606,78 @@ F841_3.py:102:5: F841 [*] Local variable `toplevel` is assigned to but never use
 104 104 | 
 105 105 | def f():
 
+F841_3.py:102:17: F841 [*] Local variable `a` is assigned to but never used
+    |
+101 | def f():
+102 |     toplevel = (a, b) = lexer.get_token()
+    |                 ^ F841
+    |
+    = help: Remove assignment to unused variable `a`
+
+ℹ Unsafe fix
+99  99  | 
+100 100 | 
+101 101 | def f():
+102     |-    toplevel = (a, b) = lexer.get_token()
+    102 |+    toplevel = (_a, b) = lexer.get_token()
+103 103 | 
+104 104 | 
+105 105 | def f():
+
+F841_3.py:102:20: F841 [*] Local variable `b` is assigned to but never used
+    |
+101 | def f():
+102 |     toplevel = (a, b) = lexer.get_token()
+    |                    ^ F841
+    |
+    = help: Remove assignment to unused variable `b`
+
+ℹ Unsafe fix
+99  99  | 
+100 100 | 
+101 101 | def f():
+102     |-    toplevel = (a, b) = lexer.get_token()
+    102 |+    toplevel = (a, _b) = lexer.get_token()
+103 103 | 
+104 104 | 
+105 105 | def f():
+
+F841_3.py:106:6: F841 [*] Local variable `a` is assigned to but never used
+    |
+105 | def f():
+106 |     (a, b) = toplevel = lexer.get_token()
+    |      ^ F841
+    |
+    = help: Remove assignment to unused variable `a`
+
+ℹ Unsafe fix
+103 103 | 
+104 104 | 
+105 105 | def f():
+106     |-    (a, b) = toplevel = lexer.get_token()
+    106 |+    (_a, b) = toplevel = lexer.get_token()
+107 107 | 
+108 108 | 
+109 109 | def f():
+
+F841_3.py:106:9: F841 [*] Local variable `b` is assigned to but never used
+    |
+105 | def f():
+106 |     (a, b) = toplevel = lexer.get_token()
+    |         ^ F841
+    |
+    = help: Remove assignment to unused variable `b`
+
+ℹ Unsafe fix
+103 103 | 
+104 104 | 
+105 105 | def f():
+106     |-    (a, b) = toplevel = lexer.get_token()
+    106 |+    (a, _b) = toplevel = lexer.get_token()
+107 107 | 
+108 108 | 
+109 109 | def f():
+
 F841_3.py:106:14: F841 [*] Local variable `toplevel` is assigned to but never used
     |
 105 | def f():
@@ -712,5 +900,3 @@ F841_3.py:173:6: F841 [*] Local variable `x` is assigned to but never used
 172 172 |     ((x)) = foo()
 173     |-    (x) = (y.z) = foo()
     173 |+    (y.z) = foo()
-
-

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_4.py.snap

@@ -20,4 +20,40 @@ F841_4.py:12:5: F841 [*] Local variable `a` is assigned to but never used
 14 14 | 
 15 15 | 
 
+F841_4.py:13:5: F841 [*] Local variable `b` is assigned to but never used
+   |
+11 | def bar():
+12 |     a = foo()
+13 |     b, c = foo()
+   |     ^ F841
+   |
+   = help: Remove assignment to unused variable `b`
 
+ℹ Unsafe fix
+10 10 | 
+11 11 | def bar():
+12 12 |     a = foo()
+13    |-    b, c = foo()
+   13 |+    _b, c = foo()
+14 14 | 
+15 15 | 
+16 16 | def baz():
+
+F841_4.py:13:8: F841 [*] Local variable `c` is assigned to but never used
+   |
+11 | def bar():
+12 |     a = foo()
+13 |     b, c = foo()
+   |        ^ F841
+   |
+   = help: Remove assignment to unused variable `c`
+
+ℹ Unsafe fix
+10 10 | 
+11 11 | def bar():
+12 12 |     a = foo()
+13    |-    b, c = foo()
+   13 |+    b, _c = foo()
+14 14 | 
+15 15 | 
+16 16 | def baz():

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__f841_dummy_variable_rgx.snap

@@ -60,6 +60,44 @@ F841_0.py:21:9: F841 Local variable `b` is assigned to but never used
    |
    = help: Remove assignment to unused variable `b`
 
+F841_0.py:24:6: F841 Local variable `c` is assigned to but never used
+   |
+23 |     bar = (1, 2)
+24 |     (c, d) = bar
+   |      ^ F841
+25 | 
+26 |     (x, y) = baz = bar
+   |
+   = help: Remove assignment to unused variable `c`
+
+F841_0.py:24:9: F841 Local variable `d` is assigned to but never used
+   |
+23 |     bar = (1, 2)
+24 |     (c, d) = bar
+   |         ^ F841
+25 | 
+26 |     (x, y) = baz = bar
+   |
+   = help: Remove assignment to unused variable `d`
+
+F841_0.py:26:6: F841 Local variable `x` is assigned to but never used
+   |
+24 |     (c, d) = bar
+25 | 
+26 |     (x, y) = baz = bar
+   |      ^ F841
+   |
+   = help: Remove assignment to unused variable `x`
+
+F841_0.py:26:9: F841 Local variable `y` is assigned to but never used
+   |
+24 |     (c, d) = bar
+25 | 
+26 |     (x, y) = baz = bar
+   |         ^ F841
+   |
+   = help: Remove assignment to unused variable `y`
+
 F841_0.py:26:14: F841 [*] Local variable `baz` is assigned to but never used
    |
 24 |     (c, d) = bar
@@ -156,6 +194,26 @@ F841_0.py:51:9: F841 [*] Local variable `b` is assigned to but never used
 53 53 |     def d():
 54 54 |         nonlocal b
 
+F841_0.py:66:24: F841 Local variable `connection` is assigned to but never used
+   |
+64 |         return None, None
+65 | 
+66 |     with connect() as (connection, cursor):
+   |                        ^^^^^^^^^^ F841
+67 |         cursor.execute("SELECT * FROM users")
+   |
+   = help: Remove assignment to unused variable `connection`
+
+F841_0.py:74:24: F841 Local variable `connection` is assigned to but never used
+   |
+72 |         return None, None
+73 | 
+74 |     with connect() as (connection, cursor):
+   |                        ^^^^^^^^^^ F841
+75 |         cursor.execute("SELECT * FROM users")
+   |
+   = help: Remove assignment to unused variable `connection`
+
 F841_0.py:79:26: F841 [*] Local variable `my_file` is assigned to but never used
    |
 78 | def f():
@@ -175,6 +233,24 @@ F841_0.py:79:26: F841 [*] Local variable `my_file` is assigned to but never used
 81 81 | 
 82 82 | 
 
+F841_0.py:79:49: F841 Local variable `this` is assigned to but never used
+   |
+78 | def f():
+79 |     with open("file") as my_file, open("") as ((this, that)):
+   |                                                 ^^^^ F841
+80 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `this`
+
+F841_0.py:79:55: F841 Local variable `that` is assigned to but never used
+   |
+78 | def f():
+79 |     with open("file") as my_file, open("") as ((this, that)):
+   |                                                       ^^^^ F841
+80 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `that`
+
 F841_0.py:85:25: F841 [*] Local variable `my_file` is assigned to but never used
    |
 83 | def f():
@@ -196,6 +272,28 @@ F841_0.py:85:25: F841 [*] Local variable `my_file` is assigned to but never used
 87 87 |     ):
 88 88 |         print("hello")
 
+F841_0.py:86:23: F841 Local variable `this` is assigned to but never used
+   |
+84 |     with (
+85 |         open("file") as my_file,
+86 |         open("") as ((this, that)),
+   |                       ^^^^ F841
+87 |     ):
+88 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `this`
+
+F841_0.py:86:29: F841 Local variable `that` is assigned to but never used
+   |
+84 |     with (
+85 |         open("file") as my_file,
+86 |         open("") as ((this, that)),
+   |                             ^^^^ F841
+87 |     ):
+88 |         print("hello")
+   |
+   = help: Remove assignment to unused variable `that`
+
 F841_0.py:102:5: F841 [*] Local variable `msg3` is assigned to but never used
     |
 100 |     msg1 = "Hello, world!"
@@ -273,5 +371,3 @@ F841_0.py:152:25: F841 [*] Local variable `_` is assigned to but never used
 152     |-    except Exception as _:
     152 |+    except Exception:
 153 153 |         pass
-
-

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__preview__F841_F841_4.py.snap

@@ -1,61 +0,0 @@
----
-source: crates/ruff_linter/src/rules/pyflakes/mod.rs
----
-F841_4.py:12:5: F841 [*] Local variable `a` is assigned to but never used
-   |
-11 | def bar():
-12 |     a = foo()
-   |     ^ F841
-13 |     b, c = foo()
-   |
-   = help: Remove assignment to unused variable `a`
-
-ℹ Unsafe fix
-9  9  | 
-10 10 | 
-11 11 | def bar():
-12    |-    a = foo()
-   12 |+    foo()
-13 13 |     b, c = foo()
-14 14 | 
-15 15 | 
-
-F841_4.py:13:5: F841 [*] Local variable `b` is assigned to but never used
-   |
-11 | def bar():
-12 |     a = foo()
-13 |     b, c = foo()
-   |     ^ F841
-   |
-   = help: Remove assignment to unused variable `b`
-
-ℹ Unsafe fix
-10 10 | 
-11 11 | def bar():
-12 12 |     a = foo()
-13    |-    b, c = foo()
-   13 |+    _b, c = foo()
-14 14 | 
-15 15 | 
-16 16 | def baz():
-
-F841_4.py:13:8: F841 [*] Local variable `c` is assigned to but never used
-   |
-11 | def bar():
-12 |     a = foo()
-13 |     b, c = foo()
-   |        ^ F841
-   |
-   = help: Remove assignment to unused variable `c`
-
-ℹ Unsafe fix
-10 10 | 
-11 11 | def bar():
-12 12 |     a = foo()
-13    |-    b, c = foo()
-   13 |+    b, _c = foo()
-14 14 | 
-15 15 | 
-16 16 | def baz():
-
-

crates/ruff_linter/src/rules/ruff/mod.rs

@@ -49,7 +49,6 @@ mod tests {
     #[test_case(Rule::UnsortedDunderAll, Path::new("RUF022.py"))]
     #[test_case(Rule::UnsortedDunderSlots, Path::new("RUF023.py"))]
     #[test_case(Rule::MutableFromkeysValue, Path::new("RUF024.py"))]
-    #[test_case(Rule::UnnecessaryDictComprehensionForIterable, Path::new("RUF025.py"))]
     #[test_case(Rule::DefaultFactoryKwarg, Path::new("RUF026.py"))]
     #[test_case(Rule::MissingFStringSyntax, Path::new("RUF027_0.py"))]
     #[test_case(Rule::MissingFStringSyntax, Path::new("RUF027_1.py"))]

crates/ruff_linter/src/rules/ruff/rules/mod.rs

@@ -24,7 +24,6 @@ pub(crate) use sort_dunder_slots::*;
 pub(crate) use static_key_dict_comprehension::*;
 #[cfg(any(feature = "test-rules", test))]
 pub(crate) use test_rules::*;
-pub(crate) use unnecessary_dict_comprehension_for_iterable::*;
 pub(crate) use unnecessary_iterable_allocation_for_first_element::*;
 pub(crate) use unnecessary_key_check::*;
 pub(crate) use unused_async::*;
@@ -61,7 +60,6 @@ mod static_key_dict_comprehension;
 mod suppression_comment_visitor;
 #[cfg(any(feature = "test-rules", test))]
 pub(crate) mod test_rules;
-mod unnecessary_dict_comprehension_for_iterable;
 mod unnecessary_iterable_allocation_for_first_element;
 mod unnecessary_key_check;
 mod unused_async;

crates/ruff_linter/src/settings/types.rs

@@ -130,13 +130,23 @@ impl PythonVersion {
     }
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, CacheKey, is_macro::Is)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, CacheKey)]
 pub enum PreviewMode {
     #[default]
     Disabled,
     Enabled,
 }
 
+impl PreviewMode {
+    pub const fn is_enabled(self) -> bool {
+        matches!(self, PreviewMode::Enabled)
+    }
+
+    pub const fn is_disabled(self) -> bool {
+        matches!(self, PreviewMode::Disabled)
+    }
+}
+
 impl From<bool> for PreviewMode {
     fn from(version: bool) -> Self {
         if version {

crates/ruff_workspace/src/options.rs

@@ -1306,7 +1306,7 @@ pub struct Flake8ImportConventionsOptions {
     /// The conventional aliases for imports. These aliases can be extended by
     /// the [`extend-aliases`](#lint_flake8-import-conventions_extend-aliases) option.
     #[option(
-        default = r#"{"altair": "alt", "matplotlib": "mpl", "matplotlib.pyplot": "plt", "numpy": "np", "pandas": "pd", "seaborn": "sns", "tensorflow": "tf", "tkinter":  "tk", "holoviews": "hv", "panel": "pn", "plotly.express": "px", "polars": "pl", "pyarrow": "pa"}"#,
+        default = r#"{"altair": "alt", "matplotlib": "mpl", "matplotlib.pyplot": "plt", "numpy": "np", "pandas": "pd", "seaborn": "sns", "tensorflow": "tf", "tkinter":  "tk", "holoviews": "hv", "panel": "pn", "plotly.express": "px", "polars": "pl", "pyarrow": "pa", "xml.etree.ElementTree": "ET"}"#,
         value_type = "dict[str, str]",
         scope = "aliases",
         example = r#"

ruff.schema.json

@@ -2833,6 +2833,8 @@
         "C417",
         "C418",
         "C419",
+        "C42",
+        "C420",
         "C9",
         "C90",
         "C901",
@@ -3728,7 +3730,6 @@
         "RUF022",
         "RUF023",
         "RUF024",
-        "RUF025",
         "RUF026",
         "RUF027",
         "RUF028",