Format expr generator exp (#5804)

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/generator_exp.py

@@ -0,0 +1,27 @@
+(a for b in c)
+
+# parens around generator expression not required
+len(a for b in c)
+
+# parens around generator expression required
+sum((a for b in c), start=0)
+
+# black keeps these atm, but intends to remove them in the future:
+# https://github.com/psf/black/issues/2943
+f((1 for _ in a))
+
+# make sure source parenthesis detection isn't fooled by these
+f((1) for _ in (a))
+
+# combination of the two above
+f(((1) for _ in (a)))
+
+
+# black keeps these atm, but intends to remove them in the future:
+# https://github.com/psf/black/issues/2943
+len(
+    ( # leading
+    a for b in c
+     # trailing
+    )
+)

crates/ruff_python_formatter/src/expression/expr_call.rs

@@ -6,6 +6,7 @@ use ruff_python_ast::node::AnyNodeRef;
 use ruff_python_whitespace::{SimpleTokenizer, TokenKind};
 
 use crate::comments::dangling_comments;
+use crate::expression::expr_generator_exp::GeneratorExpParentheses;
 use crate::expression::parentheses::{
     parenthesized, NeedsParentheses, OptionalParentheses, Parentheses,
 };
@@ -50,13 +51,23 @@ impl FormatNodeRule<ExprCall> for FormatExprCall {
             let mut joiner = f.join_comma_separated(item.end());
             match args.as_slice() {
                 [argument] if keywords.is_empty() => {
-                    let parentheses =
+                    match argument {
-                        if is_single_argument_parenthesized(argument, item.end(), source) {
+                        Expr::GeneratorExp(generator_exp) => joiner.entry(
-                            Parentheses::Always
+                            generator_exp,
-                        } else {
+                            &generator_exp
-                            Parentheses::Never
+                                .format()
-                        };
+                                .with_options(GeneratorExpParentheses::StripIfOnlyFunctionArg),
-                    joiner.entry(argument, &argument.format().with_options(parentheses));
+                        ),
+                        other => {
+                            let parentheses =
+                                if is_single_argument_parenthesized(argument, item.end(), source) {
+                                    Parentheses::Always
+                                } else {
+                                    Parentheses::Never
+                                };
+                            joiner.entry(other, &other.format().with_options(parentheses))
+                        }
+                    };
                 }
                 arguments => {
                     joiner

crates/ruff_python_formatter/src/expression/expr_generator_exp.rs

@@ -1,21 +1,76 @@
 use crate::context::PyFormatContext;
+use crate::expression::parentheses::parenthesized;
 use crate::expression::parentheses::{NeedsParentheses, OptionalParentheses};
-use crate::{not_yet_implemented_custom_text, FormatNodeRule, PyFormatter};
+use crate::prelude::*;
-use ruff_formatter::{write, Buffer, FormatResult};
+use crate::AsFormat;
+use crate::{FormatNodeRule, PyFormatter};
+use ruff_formatter::{format_args, write, Buffer, FormatResult, FormatRuleWithOptions};
 use ruff_python_ast::node::AnyNodeRef;
 use rustpython_parser::ast::ExprGeneratorExp;
 
+#[derive(Eq, PartialEq, Debug, Default)]
+pub enum GeneratorExpParentheses {
+    #[default]
+    Default,
+
+    // skip parens if the generator exp is the only argument to a function, e.g.
+    // ```python
+    //  all(x for y in z)`
+    //  ```
+    StripIfOnlyFunctionArg,
+}
+
+impl FormatRuleWithOptions<ExprGeneratorExp, PyFormatContext<'_>> for FormatExprGeneratorExp {
+    type Options = GeneratorExpParentheses;
+
+    fn with_options(mut self, options: Self::Options) -> Self {
+        self.parentheses = options;
+        self
+    }
+}
+
 #[derive(Default)]
-pub struct FormatExprGeneratorExp;
+pub struct FormatExprGeneratorExp {
+    parentheses: GeneratorExpParentheses,
+}
 
 impl FormatNodeRule<ExprGeneratorExp> for FormatExprGeneratorExp {
-    fn fmt_fields(&self, _item: &ExprGeneratorExp, f: &mut PyFormatter) -> FormatResult<()> {
+    fn fmt_fields(&self, item: &ExprGeneratorExp, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(
+        let ExprGeneratorExp {
-            f,
+            range: _,
-            [not_yet_implemented_custom_text(
+            elt,
-                "(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])"
+            generators,
-            )]
+        } = item;
-        )
+
+        let joined = format_with(|f| {
+            f.join_with(soft_line_break_or_space())
+                .entries(generators.iter().formatted())
+                .finish()
+        });
+
+        if self.parentheses == GeneratorExpParentheses::StripIfOnlyFunctionArg {
+            write!(
+                f,
+                [
+                    group(&elt.format()),
+                    soft_line_break_or_space(),
+                    group(&joined),
+                ]
+            )
+        } else {
+            write!(
+                f,
+                [parenthesized(
+                    "(",
+                    &format_args!(
+                        group(&elt.format()),
+                        soft_line_break_or_space(),
+                        group(&joined)
+                    ),
+                    ")"
+                )]
+            )
+        }
     }
 }
 

crates/ruff_python_formatter/tests/snapshots/black_compatibility@conditional_expression.py.snap

@@ -121,34 +121,20 @@ def something():
  ):
      pass
  
-@@ -59,26 +53,14 @@
+@@ -60,11 +54,9 @@
-     else "this one is a little shorter"
  )
  
--generator_expression = (
+ generator_expression = (
 -    (
 -        some_long_value_name_foo_bar_baz
 -        if some_boolean_variable
 -        else some_fallback_value_foo_bar_baz
 -    )
--    for some_boolean_variable in some_iterable
++    some_long_value_name_foo_bar_baz
--)
++    if some_boolean_variable
-+generator_expression = (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
++    else some_fallback_value_foo_bar_baz
- 
+     for some_boolean_variable in some_iterable
- 
+ )
- def limit_offset_sql(self, low_mark, high_mark):
-     """Return LIMIT/OFFSET SQL clause."""
-     limit, offset = self._get_limit_offset_params(low_mark, high_mark)
-     return " ".join(
--        sql
--        for sql in (
--            "LIMIT %d" % limit if limit else None,
--            ("OFFSET %d" % offset) if offset else None,
--        )
--        if sql
-+        (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-     )
- 
  
 ```
 
@@ -210,14 +196,24 @@ nested = (
     else "this one is a little shorter"
 )
 
-generator_expression = (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
+generator_expression = (
+    some_long_value_name_foo_bar_baz
+    if some_boolean_variable
+    else some_fallback_value_foo_bar_baz
+    for some_boolean_variable in some_iterable
+)
 
 
 def limit_offset_sql(self, low_mark, high_mark):
     """Return LIMIT/OFFSET SQL clause."""
     limit, offset = self._get_limit_offset_params(low_mark, high_mark)
     return " ".join(
-        (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
+        sql
+        for sql in (
+            "LIMIT %d" % limit if limit else None,
+            ("OFFSET %d" % offset) if offset else None,
+        )
+        if sql
     )
 
 

crates/ruff_python_formatter/tests/snapshots/black_compatibility@py_310__pattern_matching_generic.py.snap

@@ -134,7 +134,7 @@ with match() as match:
  
  
  def get_grammars(target_versions: Set[TargetVersion]) -> List[Grammar]:
-@@ -23,13 +23,11 @@
+@@ -23,11 +23,7 @@
              pygram.python_grammar,
          ]
  
@@ -145,14 +145,9 @@ with match() as match:
 -                    pass
 +    NOT_YET_IMPLEMENTED_StmtMatch
  
--    if all(version.is_python2() for version in target_versions):
+     if all(version.is_python2() for version in target_versions):
-+    if all(
-+        (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-+    ):
          # Python 2-only code, so try Python 2 grammars.
-         return [
+@@ -41,13 +37,11 @@
-             # Python 2.7 with future print_function import
-@@ -41,13 +39,11 @@
      re.match()
      match = a
      with match() as match:
@@ -168,7 +163,7 @@ with match() as match:
          self.assertIs(x, False)
          self.assertEqual(y, 0)
          self.assertIs(z, x)
-@@ -72,16 +68,12 @@
+@@ -72,16 +66,12 @@
      def test_patma_155(self):
          x = 0
          y = None
@@ -187,7 +182,7 @@ with match() as match:
  
      # At least one of the above branches must have been taken, because every Python
      # version has exactly one of the two 'ASYNC_*' flags
-@@ -99,9 +91,9 @@
+@@ -99,9 +89,9 @@
  re.match()
  match = a
  with match() as match:
@@ -231,9 +226,7 @@ def get_grammars(target_versions: Set[TargetVersion]) -> List[Grammar]:
 
     NOT_YET_IMPLEMENTED_StmtMatch
 
-    if all(
+    if all(version.is_python2() for version in target_versions):
-        (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-    ):
         # Python 2-only code, so try Python 2 grammars.
         return [
             # Python 2.7 with future print_function import

crates/ruff_python_formatter/tests/snapshots/black_compatibility@py_310__pep_572_py310.py.snap

@@ -27,7 +27,7 @@ f(x, (a := b + c for c in range(10)), y=z, **q)
 ```diff
 --- Black
 +++ Ruff
-@@ -1,15 +1,20 @@
+@@ -1,7 +1,7 @@
  # Unparenthesized walruses are now allowed in indices since Python 3.10.
 -x[a:=0]
 -x[a:=0, b:=1]
@@ -37,25 +37,7 @@ f(x, (a := b + c for c in range(10)), y=z, **q)
 +x[5, b := 0]
  
  # Walruses are allowed inside generator expressions on function calls since 3.10.
--if any(match := pattern_error.match(s) for s in buffer):
+ if any(match := pattern_error.match(s) for s in buffer):
-+if any((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])):
-     if match.group(2) == data_not_available:
-         # Error OK to ignore.
-         pass
- 
--f(a := b + c for c in range(10))
--f((a := b + c for c in range(10)), x)
--f(y=(a := b + c for c in range(10)))
--f(x, (a := b + c for c in range(10)), y=z, **q)
-+f((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []))
-+f((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []), x)
-+f(y=(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []))
-+f(
-+    x,
-+    (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []),
-+    y=z,
-+    **q,
-+)
 ```
 
 ## Ruff Output
@@ -67,20 +49,15 @@ x[a := 0, b := 1]
 x[5, b := 0]
 
 # Walruses are allowed inside generator expressions on function calls since 3.10.
-if any((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])):
+if any(match := pattern_error.match(s) for s in buffer):
     if match.group(2) == data_not_available:
         # Error OK to ignore.
         pass
 
-f((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []))
+f(a := b + c for c in range(10))
-f((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []), x)
+f((a := b + c for c in range(10)), x)
-f(y=(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []))
+f(y=(a := b + c for c in range(10)))
-f(
+f(x, (a := b + c for c in range(10)), y=z, **q)
-    x,
-    (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []),
-    y=z,
-    **q,
-)
 ```
 
 ## Black Output

crates/ruff_python_formatter/tests/snapshots/black_compatibility@py_37__python37.py.snap

@@ -1,142 +0,0 @@
----
-source: crates/ruff_python_formatter/tests/fixtures.rs
-input_file: crates/ruff_python_formatter/resources/test/fixtures/black/py_37/python37.py
----
-## Input
-
-```py
-#!/usr/bin/env python3.7
-
-
-def f():
-    return (i * 2 async for i in arange(42))
-
-
-def g():
-    return (
-        something_long * something_long
-        async for something_long in async_generator(with_an_argument)
-    )
-
-
-async def func():
-    if test:
-        out_batched = [
-            i
-            async for i in aitertools._async_map(
-                self.async_inc, arange(8), batch_size=3
-            )
-        ]
-
-
-def awaited_generator_value(n):
-    return (await awaitable for awaitable in awaitable_list)
-
-
-def make_arange(n):
-    return (i * 2 for i in range(n) if await wrap(i))
-```
-
-## Black Differences
-
-```diff
---- Black
-+++ Ruff
-@@ -2,14 +2,11 @@
- 
- 
- def f():
--    return (i * 2 async for i in arange(42))
-+    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
- 
- 
- def g():
--    return (
--        something_long * something_long
--        async for something_long in async_generator(with_an_argument)
--    )
-+    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
- 
- 
- async def func():
-@@ -23,8 +20,8 @@
- 
- 
- def awaited_generator_value(n):
--    return (await awaitable for awaitable in awaitable_list)
-+    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
- 
- 
- def make_arange(n):
--    return (i * 2 for i in range(n) if await wrap(i))
-+    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-```
-
-## Ruff Output
-
-```py
-#!/usr/bin/env python3.7
-
-
-def f():
-    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-
-
-def g():
-    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-
-
-async def func():
-    if test:
-        out_batched = [
-            i
-            async for i in aitertools._async_map(
-                self.async_inc, arange(8), batch_size=3
-            )
-        ]
-
-
-def awaited_generator_value(n):
-    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-
-
-def make_arange(n):
-    return (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-```
-
-## Black Output
-
-```py
-#!/usr/bin/env python3.7
-
-
-def f():
-    return (i * 2 async for i in arange(42))
-
-
-def g():
-    return (
-        something_long * something_long
-        async for something_long in async_generator(with_an_argument)
-    )
-
-
-async def func():
-    if test:
-        out_batched = [
-            i
-            async for i in aitertools._async_map(
-                self.async_inc, arange(8), batch_size=3
-            )
-        ]
-
-
-def awaited_generator_value(n):
-    return (await awaitable for awaitable in awaitable_list)
-
-
-def make_arange(n):
-    return (i * 2 for i in range(n) if await wrap(i))
-```
-
-

crates/ruff_python_formatter/tests/snapshots/black_compatibility@py_38__pep_572.py.snap

@@ -83,12 +83,9 @@ while x := f(x):
  x = (y := 0)
  (z := (y := (x := 0)))
  (info := (name, phone, *rest))
-@@ -31,9 +31,9 @@
+@@ -33,7 +33,7 @@
- len(lines := f.readlines())
- foo(x := 3, cat="vector")
  foo(cat=(category := "vector"))
--if any(len(longline := l) >= 100 for l in lines):
+ if any(len(longline := l) >= 100 for l in lines):
-+if any((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])):
      print(longline)
 -if env_base := os.environ.get("PYTHONUSERBASE", None):
 +if (env_base := os.environ.get("PYTHONUSERBASE", None)):
@@ -143,7 +140,7 @@ x = (y := 0)
 len(lines := f.readlines())
 foo(x := 3, cat="vector")
 foo(cat=(category := "vector"))
-if any((NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])):
+if any(len(longline := l) >= 100 for l in lines):
     print(longline)
 if (env_base := os.environ.get("PYTHONUSERBASE", None)):
     return env_base

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__expression.py.snap

@@ -363,21 +363,6 @@ last_call()
  numpy[np.newaxis, :]
  (str or None) if (sys.version_info[0] > (3,)) else (str or bytes or None)
  {"2.7": dead, "3.7": long_live or die_hard}
-@@ -181,10 +187,10 @@
- (SomeName)
- SomeName
- (Good, Bad, Ugly)
--(i for i in (1, 2, 3))
--((i**2) for i in (1, 2, 3))
--((i**2) for i, _ in ((1, "a"), (2, "b"), (3, "c")))
--(((i**2) + j) for i in (1, 2, 3) for j in (1, 2, 3))
-+(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-+(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-+(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
-+(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
- (*starred,)
- {
-     "id": "1",
 @@ -208,24 +214,14 @@
  what_is_up_with_those_new_coord_names = (coord_names | set(vars_to_create)) - set(
      vars_to_remove
@@ -435,15 +420,6 @@ last_call()
  assert not Test, "Short message"
  assert this is ComplexTest and not requirements.fit_in_a_single_line(
      force=False
-@@ -259,7 +255,7 @@
-     ...
- for y in ():
-     ...
--for z in (i for i in (1, 2, 3)):
-+for z in (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []):
-     ...
- for i in call():
-     ...
 @@ -328,13 +324,18 @@
  ):
      return True
@@ -670,10 +646,10 @@ numpy[np.newaxis, :]
 (SomeName)
 SomeName
 (Good, Bad, Ugly)
-(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
+(i for i in (1, 2, 3))
-(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
+((i**2) for i in (1, 2, 3))
-(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
+((i**2) for i, _ in ((1, "a"), (2, "b"), (3, "c")))
-(NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
+(((i**2) + j) for i in (1, 2, 3) for j in (1, 2, 3))
 (*starred,)
 {
     "id": "1",
@@ -738,7 +714,7 @@ for (x,) in (1,), (2,), (3,):
     ...
 for y in ():
     ...
-for z in (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []):
+for z in (i for i in (1, 2, 3)):
     ...
 for i in call():
     ...

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__slices.py.snap

@@ -43,7 +43,7 @@ ham[lower + offset : upper + offset]
 ```diff
 --- Black
 +++ Ruff
-@@ -4,19 +4,21 @@
+@@ -4,19 +4,19 @@
  slice[d::d]
  slice[0]
  slice[-1]
@@ -63,16 +63,13 @@ ham[lower + offset : upper + offset]
 +slice[lambda NOT_YET_IMPLEMENTED_lambda: True :, None::]
  slice[1 or 2 : True and False]
  slice[not so_simple : 1 < val <= 10]
--slice[(1 for i in range(42)) : x]
+ slice[(1 for i in range(42)) : x]
 -slice[:: [i for i in range(42)]]
-+slice[
-+    (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []) : x
-+]
 +slice[ :: [i for i in range(42)]]
  
  
  async def f():
-@@ -27,5 +29,5 @@
+@@ -27,5 +27,5 @@
  ham[1:9], ham[1:9:3], ham[:9:3], ham[1::3], ham[1:9:]
  ham[lower:upper], ham[lower:upper:], ham[lower::step]
  # ham[lower+offset : upper+offset]
@@ -101,9 +98,7 @@ slice[lambda NOT_YET_IMPLEMENTED_lambda: True : lambda NOT_YET_IMPLEMENTED_lambd
 slice[lambda NOT_YET_IMPLEMENTED_lambda: True :, None::]
 slice[1 or 2 : True and False]
 slice[not so_simple : 1 < val <= 10]
-slice[
+slice[(1 for i in range(42)) : x]
-    (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []) : x
-]
 slice[ :: [i for i in range(42)]]
 
 

crates/ruff_python_formatter/tests/snapshots/format@expression__binary.py.snap

@@ -283,7 +283,7 @@ aaaaaaaaaaaaaa + [
 ]
 (
     aaaaaaaaaaaaaa
-    + (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in [])
+    + (a for x in bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb)
 )
 aaaaaaaaaaaaaa + {
     a

crates/ruff_python_formatter/tests/snapshots/format@expression__generator_exp.py.snap

@@ -0,0 +1,68 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+input_file: crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/generator_exp.py
+---
+## Input
+```py
+(a for b in c)
+
+# parens around generator expression not required
+len(a for b in c)
+
+# parens around generator expression required
+sum((a for b in c), start=0)
+
+# black keeps these atm, but intends to remove them in the future:
+# https://github.com/psf/black/issues/2943
+f((1 for _ in a))
+
+# make sure source parenthesis detection isn't fooled by these
+f((1) for _ in (a))
+
+# combination of the two above
+f(((1) for _ in (a)))
+
+
+# black keeps these atm, but intends to remove them in the future:
+# https://github.com/psf/black/issues/2943
+len(
+    ( # leading
+    a for b in c
+     # trailing
+    )
+)
+```
+
+## Output
+```py
+(a for b in c)
+
+# parens around generator expression not required
+len(a for b in c)
+
+# parens around generator expression required
+sum((a for b in c), start=0)
+
+# black keeps these atm, but intends to remove them in the future:
+# https://github.com/psf/black/issues/2943
+f(1 for _ in a)
+
+# make sure source parenthesis detection isn't fooled by these
+f((1) for _ in (a))
+
+# combination of the two above
+f((1) for _ in (a))
+
+
+# black keeps these atm, but intends to remove them in the future:
+# https://github.com/psf/black/issues/2943
+len(
+    # leading
+    a
+    for b in c
+    # trailing
+)
+```
+
+
+

crates/ruff_python_formatter/tests/snapshots/format@statement__with.py.snap

@@ -163,7 +163,7 @@ with aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
 
 
 # currently unparsable by black: https://github.com/psf/black/issues/3678
-with (NOT_YET_IMPLEMENTED_generator_key for NOT_YET_IMPLEMENTED_generator_key in []):
+with (name_2 for name_0 in name_4):
     pass
 with (a, *b):
     pass