[flake8-comprehensions] strip parentheses around generators in `unn…

…ecessary-generator-set` (`C401`) (astral-sh#15553)

<!--
Thank you for contributing to Ruff! To help us out with reviewing,
please consider the following:

- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title?
- Does this pull request include references to any relevant issues?
-->

## Summary

Fixes parentheses not being stripped in C401. Pretty much the same as
astral-sh#11607 which fixed it for C400.

## Test Plan
`cargo nextest run`

crates/ruff_linter/resources/test/fixtures/flake8_comprehensions/C401.py

@@ -1,4 +1,4 @@
-# Cannot conbime with C416. Should use set comprehension here.
+# Cannot combine with C416. Should use set comprehension here.
 even_nums = set(2 * x for x in range(3))
 odd_nums = set(
     2 * x + 1 for x in range(3)
@@ -21,6 +21,10 @@ def f(x):
 print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
 print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
 
+# Strip parentheses from inner generators.
+set((2 * x for x in range(3)))
+set(((2 * x for x in range(3))))
+set((((2 * x for x in range(3)))))
 
 # Not built-in set.
 def set(*args, **kwargs):

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

@@ -2,6 +2,7 @@ use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, ViolationMetadata};
 use ruff_python_ast as ast;
 use ruff_python_ast::comparable::ComparableExpr;
+use ruff_python_ast::parenthesize::parenthesized_range;
 use ruff_python_ast::ExprGenerator;
 use ruff_text_size::{Ranged, TextSize};
 
@@ -27,12 +28,14 @@ use super::helpers;
 /// ```python
 /// set(f(x) for x in foo)
 /// set(x for x in foo)
+/// set((x for x in foo))
 /// ```
 ///
 /// Use instead:
 /// ```python
 /// {f(x) for x in foo}
 /// set(foo)
+/// set(foo)
 /// ```
 ///
 /// ## Fix safety
@@ -74,7 +77,10 @@ pub(crate) fn unnecessary_generator_set(checker: &mut Checker, call: &ast::ExprC
     };
 
     let ast::Expr::Generator(ExprGenerator {
-        elt, generators, ..
+        elt,
+        generators,
+        parenthesized,
+        ..
     }) = argument
     else {
         return;
@@ -126,7 +132,28 @@ pub(crate) fn unnecessary_generator_set(checker: &mut Checker, call: &ast::ExprC
             call.end(),
         );
 
-        Fix::unsafe_edits(call_start, [call_end])
+        // Remove the inner parentheses, if the expression is a generator. The easiest way to do
+        // this reliably is to use the printer.
+        if *parenthesized {
+            // The generator's range will include the innermost parentheses, but it could be
+            // surrounded by additional parentheses.
+            let range = parenthesized_range(
+                argument.into(),
+                (&call.arguments).into(),
+                checker.comment_ranges(),
+                checker.locator().contents(),
+            )
+            .unwrap_or(argument.range());
+
+            // The generator always parenthesizes the expression; trim the parentheses.
+            let generator = checker.generator().expr(argument);
+            let generator = generator[1..generator.len() - 1].to_string();
+
+            let replacement = Edit::range_replacement(generator, range);
+            Fix::unsafe_edits(call_start, [call_end, replacement])
+        } else {
+            Fix::unsafe_edits(call_start, [call_end])
+        }
     };
     checker.diagnostics.push(diagnostic.with_fix(fix));
 }

crates/ruff_linter/src/rules/flake8_comprehensions/snapshots/ruff_linter__rules__flake8_comprehensions__tests__C401_C401.py.snap

@@ -3,7 +3,7 @@ source: crates/ruff_linter/src/rules/flake8_comprehensions/mod.rs
 ---
 C401.py:2:13: C401 [*] Unnecessary generator (rewrite as a set comprehension)
   |
-1 | # Cannot conbime with C416. Should use set comprehension here.
+1 | # Cannot combine with C416. Should use set comprehension here.
 2 | even_nums = set(2 * x for x in range(3))
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
 3 | odd_nums = set(
@@ -12,7 +12,7 @@ C401.py:2:13: C401 [*] Unnecessary generator (rewrite as a set comprehension)
   = help: Rewrite as a set comprehension
 
 ℹ Unsafe fix
-1 1 | # Cannot conbime with C416. Should use set comprehension here.
+1 1 | # Cannot combine with C416. Should use set comprehension here.
 2   |-even_nums = set(2 * x for x in range(3))
   2 |+even_nums = {2 * x for x in range(3)}
 3 3 | odd_nums = set(
@@ -21,7 +21,7 @@ C401.py:2:13: C401 [*] Unnecessary generator (rewrite as a set comprehension)
 
 C401.py:3:12: C401 [*] Unnecessary generator (rewrite as a set comprehension)
   |
-1 |   # Cannot conbime with C416. Should use set comprehension here.
+1 |   # Cannot combine with C416. Should use set comprehension here.
 2 |   even_nums = set(2 * x for x in range(3))
 3 |   odd_nums = set(
   |  ____________^
@@ -33,7 +33,7 @@ C401.py:3:12: C401 [*] Unnecessary generator (rewrite as a set comprehension)
   = help: Rewrite as a set comprehension
 
 ℹ Unsafe fix
-1 1 | # Cannot conbime with C416. Should use set comprehension here.
+1 1 | # Cannot combine with C416. Should use set comprehension here.
 2 2 | even_nums = set(2 * x for x in range(3))
 3   |-odd_nums = set(
   3 |+odd_nums = {
@@ -188,7 +188,7 @@ C401.py:21:10: C401 [*] Unnecessary generator (rewrite using `set()`)
    21 |+print(f"{set('abc') - set(a for a in 'ab')}")
 22 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
 23 23 | 
-24 24 | 
+24 24 | # Strip parentheses from inner generators.
 
 C401.py:21:34: C401 [*] Unnecessary generator (rewrite using `set()`)
    |
@@ -208,14 +208,16 @@ C401.py:21:34: C401 [*] Unnecessary generator (rewrite using `set()`)
    21 |+print(f"{set(a for a in 'abc') - set('ab')}")
 22 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
 23 23 | 
-24 24 | 
+24 24 | # Strip parentheses from inner generators.
 
 C401.py:22:11: C401 [*] Unnecessary generator (rewrite using `set()`)
    |
 20 | print(f"Hello {set(a for a in range(3))} World")
 21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
    |           ^^^^^^^^^^^^^^^^^^^^^ C401
+23 |
+24 | # Strip parentheses from inner generators.
    |
    = help: Rewrite using `set()`
 
@@ -226,15 +228,17 @@ C401.py:22:11: C401 [*] Unnecessary generator (rewrite using `set()`)
 22    |-print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
    22 |+print(f"{ set('abc') - set(a for a in 'ab') }")
 23 23 | 
-24 24 | 
-25 25 | # Not built-in set.
+24 24 | # Strip parentheses from inner generators.
+25 25 | set((2 * x for x in range(3)))
 
 C401.py:22:35: C401 [*] Unnecessary generator (rewrite using `set()`)
    |
 20 | print(f"Hello {set(a for a in range(3))} World")
 21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
    |                                   ^^^^^^^^^^^^^^^^^^^^ C401
+23 |
+24 | # Strip parentheses from inner generators.
    |
    = help: Rewrite using `set()`
 
@@ -245,5 +249,66 @@ C401.py:22:35: C401 [*] Unnecessary generator (rewrite using `set()`)
 22    |-print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
    22 |+print(f"{ set(a for a in 'abc') - set('ab') }")
 23 23 | 
-24 24 | 
-25 25 | # Not built-in set.
+24 24 | # Strip parentheses from inner generators.
+25 25 | set((2 * x for x in range(3)))
+
+C401.py:25:1: C401 [*] Unnecessary generator (rewrite as a set comprehension)
+   |
+24 | # Strip parentheses from inner generators.
+25 | set((2 * x for x in range(3)))
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
+26 | set(((2 * x for x in range(3))))
+27 | set((((2 * x for x in range(3)))))
+   |
+   = help: Rewrite as a set comprehension
+
+ℹ Unsafe fix
+22 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+23 23 | 
+24 24 | # Strip parentheses from inner generators.
+25    |-set((2 * x for x in range(3)))
+   25 |+{2 * x for x in range(3)}
+26 26 | set(((2 * x for x in range(3))))
+27 27 | set((((2 * x for x in range(3)))))
+28 28 | 
+
+C401.py:26:1: C401 [*] Unnecessary generator (rewrite as a set comprehension)
+   |
+24 | # Strip parentheses from inner generators.
+25 | set((2 * x for x in range(3)))
+26 | set(((2 * x for x in range(3))))
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
+27 | set((((2 * x for x in range(3)))))
+   |
+   = help: Rewrite as a set comprehension
+
+ℹ Unsafe fix
+23 23 | 
+24 24 | # Strip parentheses from inner generators.
+25 25 | set((2 * x for x in range(3)))
+26    |-set(((2 * x for x in range(3))))
+   26 |+{2 * x for x in range(3)}
+27 27 | set((((2 * x for x in range(3)))))
+28 28 | 
+29 29 | # Not built-in set.
+
+C401.py:27:1: C401 [*] Unnecessary generator (rewrite as a set comprehension)
+   |
+25 | set((2 * x for x in range(3)))
+26 | set(((2 * x for x in range(3))))
+27 | set((((2 * x for x in range(3)))))
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
+28 |
+29 | # Not built-in set.
+   |
+   = help: Rewrite as a set comprehension
+
+ℹ Unsafe fix
+24 24 | # Strip parentheses from inner generators.
+25 25 | set((2 * x for x in range(3)))
+26 26 | set(((2 * x for x in range(3))))
+27    |-set((((2 * x for x in range(3)))))
+   27 |+{2 * x for x in range(3)}
+28 28 | 
+29 29 | # Not built-in set.
+30 30 | def set(*args, **kwargs):