[`flake8-comprehensions`] Handled special case for `C401` which also matches `C416` (#10596)

## Summary

<!-- What's the purpose of the change? What does it do, and why? -->

Similar to #10419, there was a case where there is a collision of C401
and C416 (as discussed in #10101).
Fixed this by implementing short-circuit for the comprehension of the
form `{x for x in foo}`.

## Test Plan

<!-- How was it tested? -->

Extended `C401.py` with the case where `set` is not builtin function,
and divided the case where the short-circuit should occur.
Removed the last testcase of `print(f"{ {set(a for a in 'abc')} }")`
test as this is invalid as a python code, but should I keep this?

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

@@ -1,20 +1,30 @@
-x = set(x for x in range(3))
+# Cannot conbime with C416. Should use set comprehension here.
-x = set(x for x in range(3))
+even_nums = set(2 * x for x in range(3))
-y = f"{set(a if a < 6 else 0  for a in range(3))}"
+odd_nums = set(
-_ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
+    2 * x + 1 for x in range(3)
-print(f"Hello {set(a for a in range(3))} World")
+)
-
+small_nums = f"{set(a if a < 6 else 0 for a in range(3))}"
 
 def f(x):
     return x
 
-
-print(f'Hello {set(a for a in "abc")} World')
-print(f"Hello {set(a for a in 'abc')} World")
 print(f"Hello {set(f(a) for a in 'abc')} World")
+print(f"Hello { set(f(a) for a in 'abc') } World")
+
+
+# Short-circuit case, combine with C416 and should produce x = set(range(3))
+x = set(x for x in range(3))
+x = set(
+    x for x in range(3)
+)
+print(f"Hello {set(a for a in range(3))} World")
 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') }")
 
-# The fix generated for this diagnostic is incorrect, as we add additional space
+
-# around the set comprehension.
+# Not built-in set.
-print(f"{ {set(a for a in 'abc')} }")
+def set(*args, **kwargs):
+    return None
+
+set(2 * x for x in range(3))
+set(x for x in range(3))

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

@@ -1,6 +1,8 @@
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast as ast;
+use ruff_python_ast::comparable::ComparableExpr;
+use ruff_python_ast::ExprGenerator;
 use ruff_text_size::{Ranged, TextSize};
 
 use crate::checkers::ast::Checker;
@@ -10,37 +12,53 @@ use super::helpers;
 
 /// ## What it does
 /// Checks for unnecessary generators that can be rewritten as `set`
-/// comprehensions.
+/// comprehensions (or with `set` directly).
 ///
 /// ## Why is this bad?
 /// It is unnecessary to use `set` around a generator expression, since
 /// there are equivalent comprehensions for these types. Using a
 /// comprehension is clearer and more idiomatic.
 ///
+/// Further, if the comprehension can be removed entirely, as in the case of
+/// `set(x for x in foo)`, it's better to use `set(foo)` directly, since it's
+/// even more direct.
+///
 /// ## Examples
 /// ```python
 /// set(f(x) for x in foo)
+/// set(x for x in foo)
 /// ```
 ///
 /// Use instead:
 /// ```python
 /// {f(x) for x in foo}
+/// set(foo)
 /// ```
 ///
 /// ## Fix safety
 /// This rule's fix is marked as unsafe, as it may occasionally drop comments
 /// when rewriting the call. In most cases, though, comments will be preserved.
 #[violation]
-pub struct UnnecessaryGeneratorSet;
+pub struct UnnecessaryGeneratorSet {
+    short_circuit: bool,
+}
 
 impl AlwaysFixableViolation for UnnecessaryGeneratorSet {
     #[derive_message_formats]
     fn message(&self) -> String {
-        format!("Unnecessary generator (rewrite as a `set` comprehension)")
+        if self.short_circuit {
+            format!("Unnecessary generator (rewrite using `set()`")
+        } else {
+            format!("Unnecessary generator (rewrite as a `set` comprehension)")
+        }
     }
 
     fn fix_title(&self) -> String {
-        "Rewrite as a `set` comprehension".to_string()
+        if self.short_circuit {
+            "Rewrite using `set()`".to_string()
+        } else {
+            "Rewrite as a `set` comprehension".to_string()
+        }
     }
 }
 
@@ -57,28 +75,59 @@ pub(crate) fn unnecessary_generator_set(checker: &mut Checker, call: &ast::ExprC
     if !checker.semantic().is_builtin("set") {
         return;
     }
-    if argument.is_generator_expr() {
-        let mut diagnostic = Diagnostic::new(UnnecessaryGeneratorSet, call.range());
 
-        // Convert `set(x for x in y)` to `{x for x in y}`.
+    let Some(ExprGenerator {
-        diagnostic.set_fix({
+        elt, generators, ..
-            // Replace `set(` with `}`.
+    }) = argument.as_generator_expr()
-            let call_start = Edit::replacement(
+    else {
-                pad_start("{", call.range(), checker.locator(), checker.semantic()),
+        return;
-                call.start(),
+    };
-                call.arguments.start() + TextSize::from(1),
-            );
 
-            // Replace `)` with `}`.
+    // Short-circuit: given `set(x for x in y)`, generate `set(y)` (in lieu of `{x for x in y}`).
-            let call_end = Edit::replacement(
+    if let [generator] = generators.as_slice() {
-                pad_end("}", call.range(), checker.locator(), checker.semantic()),
+        if generator.ifs.is_empty() && !generator.is_async {
-                call.arguments.end() - TextSize::from(1),
+            if ComparableExpr::from(elt) == ComparableExpr::from(&generator.target) {
-                call.end(),
+                let mut diagnostic = Diagnostic::new(
-            );
+                    UnnecessaryGeneratorSet {
-
+                        short_circuit: true,
-            Fix::unsafe_edits(call_start, [call_end])
+                    },
-        });
+                    call.range(),
-
+                );
-        checker.diagnostics.push(diagnostic);
+                let iterator = format!("set({})", checker.locator().slice(generator.iter.range()));
+                diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
+                    iterator,
+                    call.range(),
+                )));
+                checker.diagnostics.push(diagnostic);
+                return;
+            }
+        }
     }
+
+    // Convert `set(f(x) for x in y)` to `{f(x) for x in y}`.
+    let mut diagnostic = Diagnostic::new(
+        UnnecessaryGeneratorSet {
+            short_circuit: false,
+        },
+        call.range(),
+    );
+    diagnostic.set_fix({
+        // Replace `set(` with `}`.
+        let call_start = Edit::replacement(
+            pad_start("{", call.range(), checker.locator(), checker.semantic()),
+            call.start(),
+            call.arguments.start() + TextSize::from(1),
+        );
+
+        // Replace `)` with `}`.
+        let call_end = Edit::replacement(
+            pad_end("}", call.range(), checker.locator(), checker.semantic()),
+            call.arguments.end() - TextSize::from(1),
+            call.end(),
+        );
+
+        Fix::unsafe_edits(call_start, [call_end])
+    });
+
+    checker.diagnostics.push(diagnostic);
 }

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

@@ -1,255 +1,249 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_comprehensions/mod.rs
 ---
-C401.py:1:5: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:2:13: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
   |
-1 | x = set(x for x in range(3))
+1 | # Cannot conbime with C416. Should use set comprehension here.
-  |     ^^^^^^^^^^^^^^^^^^^^^^^^ C401
+2 | even_nums = set(2 * x for x in range(3))
-2 | x = set(x for x in range(3))
+  |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
-3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
+3 | odd_nums = set(
+4 |     2 * x + 1 for x in range(3)
   |
   = help: Rewrite as a `set` comprehension
 
 ℹ Unsafe fix
-1   |-x = set(x for x in range(3))
+1 1 | # Cannot conbime with C416. Should use set comprehension here.
-  1 |+x = {x for x in range(3)}
+2   |-even_nums = set(2 * x for x in range(3))
-2 2 | x = set(x for x in range(3))
+  2 |+even_nums = {2 * x for x in range(3)}
-3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
+3 3 | odd_nums = set(
-4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
+4 4 |     2 * x + 1 for x in range(3)
+5 5 | )
 
-C401.py:2:5: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:3:12: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
   |
-1 | x = set(x for x in range(3))
+1 |   # Cannot conbime with C416. Should use set comprehension here.
-2 | x = set(x for x in range(3))
+2 |   even_nums = set(2 * x for x in range(3))
-  |     ^^^^^^^^^^^^^^^^^^^^^^^^ C401
+3 |   odd_nums = set(
-3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
+  |  ____________^
-4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
+4 | |     2 * x + 1 for x in range(3)
+5 | | )
+  | |_^ C401
+6 |   small_nums = f"{set(a if a < 6 else 0 for a in range(3))}"
   |
   = help: Rewrite as a `set` comprehension
 
 ℹ Unsafe fix
-1 1 | x = set(x for x in range(3))
+1 1 | # Cannot conbime with C416. Should use set comprehension here.
-2   |-x = set(x for x in range(3))
+2 2 | even_nums = set(2 * x for x in range(3))
-  2 |+x = {x for x in range(3)}
+3   |-odd_nums = set(
-3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
+  3 |+odd_nums = {
-4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
+4 4 |     2 * x + 1 for x in range(3)
-5 5 | print(f"Hello {set(a for a in range(3))} World")
+5   |-)
-
+  5 |+}
-C401.py:3:8: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+6 6 | small_nums = f"{set(a if a < 6 else 0 for a in range(3))}"
-  |
-1 | x = set(x for x in range(3))
-2 | x = set(x for x in range(3))
-3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-  |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
-4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-5 | print(f"Hello {set(a for a in range(3))} World")
-  |
-  = help: Rewrite as a `set` comprehension
-
-ℹ Unsafe fix
-1 1 | x = set(x for x in range(3))
-2 2 | x = set(x for x in range(3))
-3   |-y = f"{set(a if a < 6 else 0  for a in range(3))}"
-  3 |+y = f"{ {a if a < 6 else 0  for a in range(3)} }"
-4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-5 5 | print(f"Hello {set(a for a in range(3))} World")
-6 6 | 
-
-C401.py:4:17: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
-  |
-2 | x = set(x for x in range(3))
-3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-  |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
-5 | print(f"Hello {set(a for a in range(3))} World")
-  |
-  = help: Rewrite as a `set` comprehension
-
-ℹ Unsafe fix
-1 1 | x = set(x for x in range(3))
-2 2 | x = set(x for x in range(3))
-3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-4   |-_ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-  4 |+_ = "{}".format({a if a < 6 else 0 for a in range(3)})
-5 5 | print(f"Hello {set(a for a in range(3))} World")
-6 6 | 
-7 7 | 
-
-C401.py:5:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
-  |
-3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-5 | print(f"Hello {set(a for a in range(3))} World")
-  |                ^^^^^^^^^^^^^^^^^^^^^^^^ C401
-  |
-  = help: Rewrite as a `set` comprehension
-
-ℹ Unsafe fix
-2 2 | x = set(x for x in range(3))
-3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-5   |-print(f"Hello {set(a for a in range(3))} World")
-  5 |+print(f"Hello { {a for a in range(3)} } World")
-6 6 | 
 7 7 | 
 8 8 | def f(x):
 
-C401.py:12:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:6:17: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+  |
+4 |     2 * x + 1 for x in range(3)
+5 | )
+6 | small_nums = f"{set(a if a < 6 else 0 for a in range(3))}"
+  |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
+7 | 
+8 | def f(x):
+  |
+  = help: Rewrite as a `set` comprehension
+
+ℹ Unsafe fix
+3 3 | odd_nums = set(
+4 4 |     2 * x + 1 for x in range(3)
+5 5 | )
+6   |-small_nums = f"{set(a if a < 6 else 0 for a in range(3))}"
+  6 |+small_nums = f"{ {a if a < 6 else 0 for a in range(3)} }"
+7 7 | 
+8 8 | def f(x):
+9 9 |     return x
+
+C401.py:11:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
    |
-12 | print(f'Hello {set(a for a in "abc")} World')
+ 9 |     return x
-   |                ^^^^^^^^^^^^^^^^^^^^^ C401
+10 | 
-13 | print(f"Hello {set(a for a in 'abc')} World")
+11 | print(f"Hello {set(f(a) for a in 'abc')} World")
-14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^ C401
+12 | print(f"Hello { set(f(a) for a in 'abc') } World")
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Unsafe fix
+8  8  | def f(x):
+9  9  |     return x
+10 10 | 
+11    |-print(f"Hello {set(f(a) for a in 'abc')} World")
+   11 |+print(f"Hello { {f(a) for a in 'abc'} } World")
+12 12 | print(f"Hello { set(f(a) for a in 'abc') } World")
+13 13 | 
+14 14 | 
+
+C401.py:12:17: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+11 | print(f"Hello {set(f(a) for a in 'abc')} World")
+12 | print(f"Hello { set(f(a) for a in 'abc') } World")
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^ C401
    |
    = help: Rewrite as a `set` comprehension
 
 ℹ Unsafe fix
 9  9  |     return x
 10 10 | 
-11 11 | 
+11 11 | print(f"Hello {set(f(a) for a in 'abc')} World")
-12    |-print(f'Hello {set(a for a in "abc")} World')
+12    |-print(f"Hello { set(f(a) for a in 'abc') } World")
-   12 |+print(f'Hello { {a for a in "abc"} } World')
+   12 |+print(f"Hello { {f(a) for a in 'abc'} } World")
-13 13 | print(f"Hello {set(a for a in 'abc')} World")
+13 13 | 
-14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+14 14 | 
-15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+15 15 | # Short-circuit case, combine with C416 and should produce x = set(range(3))
 
-C401.py:13:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:16:5: C401 [*] Unnecessary generator (rewrite using `set()`
    |
-12 | print(f'Hello {set(a for a in "abc")} World')
+15 | # Short-circuit case, combine with C416 and should produce x = set(range(3))
-13 | print(f"Hello {set(a for a in 'abc')} World")
+16 | x = set(x for x in range(3))
-   |                ^^^^^^^^^^^^^^^^^^^^^ C401
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ C401
-14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+17 | x = set(
-15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+18 |     x for x in range(3)
    |
-   = help: Rewrite as a `set` comprehension
+   = help: Rewrite using `set()`
 
 ℹ Unsafe fix
-10 10 | 
+13 13 | 
-11 11 | 
+14 14 | 
-12 12 | print(f'Hello {set(a for a in "abc")} World')
+15 15 | # Short-circuit case, combine with C416 and should produce x = set(range(3))
-13    |-print(f"Hello {set(a for a in 'abc')} World")
+16    |-x = set(x for x in range(3))
-   13 |+print(f"Hello { {a for a in 'abc'} } World")
+   16 |+x = set(range(3))
-14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+17 17 | x = set(
-15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+18 18 |     x for x in range(3)
-16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+19 19 | )
 
-C401.py:14:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:17:5: C401 [*] Unnecessary generator (rewrite using `set()`
    |
-12 | print(f'Hello {set(a for a in "abc")} World')
+15 |   # Short-circuit case, combine with C416 and should produce x = set(range(3))
-13 | print(f"Hello {set(a for a in 'abc')} World")
+16 |   x = set(x for x in range(3))
-14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+17 |   x = set(
+   |  _____^
+18 | |     x for x in range(3)
+19 | | )
+   | |_^ C401
+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')}")
+   |
+   = help: Rewrite using `set()`
+
+ℹ Unsafe fix
+14 14 | 
+15 15 | # Short-circuit case, combine with C416 and should produce x = set(range(3))
+16 16 | x = set(x for x in range(3))
+17    |-x = set(
+18    |-    x for x in range(3)
+19    |-)
+   17 |+x = set(range(3))
+20 18 | print(f"Hello {set(a for a in range(3))} World")
+21 19 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+22 20 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+
+C401.py:20:16: C401 [*] Unnecessary generator (rewrite using `set()`
+   |
+18 |     x for x in range(3)
+19 | )
+20 | print(f"Hello {set(a for a in range(3))} World")
    |                ^^^^^^^^^^^^^^^^^^^^^^^^ C401
-15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-16 | 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') }")
    |
-   = help: Rewrite as a `set` comprehension
+   = help: Rewrite using `set()`
 
 ℹ Unsafe fix
-11 11 | 
+17 17 | x = set(
-12 12 | print(f'Hello {set(a for a in "abc")} World')
+18 18 |     x for x in range(3)
-13 13 | print(f"Hello {set(a for a in 'abc')} World")
+19 19 | )
-14    |-print(f"Hello {set(f(a) for a in 'abc')} World")
+20    |-print(f"Hello {set(a for a in range(3))} World")
-   14 |+print(f"Hello { {f(a) for a in 'abc'} } World")
+   20 |+print(f"Hello {set(range(3))} World")
-15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+22 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
-17 17 | 
+23 23 | 
 
-C401.py:15:10: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:21:10: C401 [*] Unnecessary generator (rewrite using `set()`
    |
-13 | print(f"Hello {set(a for a in 'abc')} World")
+19 | )
-14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 | print(f"Hello {set(a for a in range(3))} World")
-15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
    |          ^^^^^^^^^^^^^^^^^^^^^ C401
-16 | 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') }")
    |
-   = help: Rewrite as a `set` comprehension
+   = help: Rewrite using `set()`
 
 ℹ Unsafe fix
-12 12 | print(f'Hello {set(a for a in "abc")} World')
+18 18 |     x for x in range(3)
-13 13 | print(f"Hello {set(a for a in 'abc')} World")
+19 19 | )
-14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 20 | print(f"Hello {set(a for a in range(3))} World")
-15    |-print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21    |-print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-   15 |+print(f"{ {a for a in 'abc'} - set(a for a in 'ab')}")
+   21 |+print(f"{set('abc') - set(a for a in 'ab')}")
-16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+22 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
-17 17 | 
+23 23 | 
-18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+24 24 | 
 
-C401.py:15:34: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:21:34: C401 [*] Unnecessary generator (rewrite using `set()`
    |
-13 | print(f"Hello {set(a for a in 'abc')} World")
+19 | )
-14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 | print(f"Hello {set(a for a in range(3))} World")
-15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
    |                                  ^^^^^^^^^^^^^^^^^^^^ C401
-16 | 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') }")
    |
-   = help: Rewrite as a `set` comprehension
+   = help: Rewrite using `set()`
 
 ℹ Unsafe fix
-12 12 | print(f'Hello {set(a for a in "abc")} World')
+18 18 |     x for x in range(3)
-13 13 | print(f"Hello {set(a for a in 'abc')} World")
+19 19 | )
-14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 20 | print(f"Hello {set(a for a in range(3))} World")
-15    |-print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21    |-print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-   15 |+print(f"{set(a for a in 'abc') - {a for a in 'ab'} }")
+   21 |+print(f"{set(a for a in 'abc') - set('ab')}")
-16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+22 22 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
-17 17 | 
+23 23 | 
-18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+24 24 | 
 
-C401.py:16:11: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:22:11: C401 [*] Unnecessary generator (rewrite using `set()`
    |
-14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 | print(f"Hello {set(a for a in range(3))} World")
-15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-16 | 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
-17 | 
-18 | # The fix generated for this diagnostic is incorrect, as we add additional space
    |
-   = help: Rewrite as a `set` comprehension
+   = help: Rewrite using `set()`
 
 ℹ Unsafe fix
-13 13 | print(f"Hello {set(a for a in 'abc')} World")
+19 19 | )
-14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 20 | print(f"Hello {set(a for a in range(3))} World")
-15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-16    |-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') }")
-   16 |+print(f"{ {a for a in 'abc'} - set(a for a in 'ab') }")
+   22 |+print(f"{ set('abc') - set(a for a in 'ab') }")
-17 17 | 
+23 23 | 
-18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+24 24 | 
-19 19 | # around the set comprehension.
+25 25 | # Not built-in set.
 
-C401.py:16:35: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:22:35: C401 [*] Unnecessary generator (rewrite using `set()`
    |
-14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 | print(f"Hello {set(a for a in range(3))} World")
-15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-16 | 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
-17 | 
-18 | # The fix generated for this diagnostic is incorrect, as we add additional space
    |
-   = help: Rewrite as a `set` comprehension
+   = help: Rewrite using `set()`
 
 ℹ Unsafe fix
-13 13 | print(f"Hello {set(a for a in 'abc')} World")
+19 19 | )
-14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+20 20 | print(f"Hello {set(a for a in range(3))} World")
-15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+21 21 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
-16    |-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') }")
-   16 |+print(f"{ set(a for a in 'abc') - {a for a in 'ab'} }")
+   22 |+print(f"{ set(a for a in 'abc') - set('ab') }")
-17 17 | 
+23 23 | 
-18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+24 24 | 
-19 19 | # around the set comprehension.
+25 25 | # Not built-in set.
-
-C401.py:20:12: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
-   |
-18 | # The fix generated for this diagnostic is incorrect, as we add additional space
-19 | # around the set comprehension.
-20 | print(f"{ {set(a for a in 'abc')} }")
-   |            ^^^^^^^^^^^^^^^^^^^^^ C401
-   |
-   = help: Rewrite as a `set` comprehension
-
-ℹ Unsafe fix
-17 17 | 
-18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
-19 19 | # around the set comprehension.
-20    |-print(f"{ {set(a for a in 'abc')} }")
-   20 |+print(f"{ { {a for a in 'abc'} } }")
-
-