[flake8-simplify] Avoid double negation in fixes (SIM103) (#16684)

## Summary

This PR stabilizes the fixes improvements made in
#15562 (released with ruff 0.9.3
in mid January).

There's no open issue or PR related to the changed fix behavior.

This is not a breaking change. The fix was only gated behind preview to
get some more test coverage before releasing.

Author: MichaReiser

crates/ruff_linter/src/rules/flake8_simplify/mod.rs

@@ -58,7 +58,6 @@ mod tests {
         Ok(())
     }
 
-    #[test_case(Rule::NeedlessBool, Path::new("SIM103.py"))]
     #[test_case(Rule::IfElseBlockInsteadOfIfExp, Path::new("SIM108.py"))]
     fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!(

crates/ruff_linter/src/rules/flake8_simplify/rules/needless_bool.rs

@@ -14,7 +14,7 @@ use crate::fix::snippet::SourceCodeSnippet;
 ///
 /// ## Why is this bad?
 /// `if` statements that return `True` for a truthy condition and `False` for
-/// a falsey condition can be replaced with boolean casts.
+/// a falsy condition can be replaced with boolean casts.
 ///
 /// ## Example
 /// Given:
@@ -42,10 +42,6 @@ use crate::fix::snippet::SourceCodeSnippet;
 /// return x > 0
 /// ```
 ///
-/// ## Preview
-/// In preview, double negations such as `not a != b`, `not a not in b`, `not a is not b`
-/// will be simplified to `a == b`, `a in b` and `a is b`, respectively.
-///
 /// ## References
 /// - [Python documentation: Truth Value Testing](https://docs.python.org/3/library/stdtypes.html#truth-value-testing)
 #[derive(ViolationMetadata)]
@@ -222,16 +218,15 @@ pub(crate) fn needless_bool(checker: &Checker, stmt: &Stmt) {
                     left,
                     comparators,
                     ..
-                }) if checker.settings.preview.is_enabled()
-                    && matches!(
-                        ops.as_ref(),
-                        [ast::CmpOp::Eq
-                            | ast::CmpOp::NotEq
-                            | ast::CmpOp::In
-                            | ast::CmpOp::NotIn
-                            | ast::CmpOp::Is
-                            | ast::CmpOp::IsNot]
-                    ) =>
+                }) if matches!(
+                    ops.as_ref(),
+                    [ast::CmpOp::Eq
+                        | ast::CmpOp::NotEq
+                        | ast::CmpOp::In
+                        | ast::CmpOp::NotIn
+                        | ast::CmpOp::Is
+                        | ast::CmpOp::IsNot]
+                ) =>
                 {
                     let ([op], [right]) = (ops.as_ref(), comparators.as_ref()) else {
                         unreachable!("Single comparison with multiple comparators");

crates/ruff_linter/src/rules/flake8_simplify/snapshots/ruff_linter__rules__flake8_simplify__tests__SIM103_SIM103.py.snap

@@ -252,15 +252,15 @@ SIM103.py:123:5: SIM103 [*] Return the condition `not 10 < a` directly
 127 125 | 
 128 126 | def f():
 
-SIM103.py:129:5: SIM103 [*] Return the condition `not 10 in a` directly
+SIM103.py:129:5: SIM103 [*] Return the condition `10 not in a` directly
     |
 128 |   def f():
 129 | /     if 10 in a:
 130 | |         return False
 131 | |     return True
     | |_______________^ SIM103
     |
-    = help: Replace with `return not 10 in a`
+    = help: Replace with `return 10 not in a`
 
 ℹ Unsafe fix
 126 126 | 
@@ -269,20 +269,20 @@ SIM103.py:129:5: SIM103 [*] Return the condition `not 10 in a` directly
 129     |-    if 10 in a:
 130     |-        return False
 131     |-    return True
-    129 |+    return not 10 in a
+    129 |+    return 10 not in a
 132 130 | 
 133 131 | 
 134 132 | def f():
 
-SIM103.py:135:5: SIM103 [*] Return the condition `not 10 not in a` directly
+SIM103.py:135:5: SIM103 [*] Return the condition `10 in a` directly
     |
 134 |   def f():
 135 | /     if 10 not in a:
 136 | |         return False
 137 | |     return True
     | |_______________^ SIM103
     |
-    = help: Replace with `return not 10 not in a`
+    = help: Replace with `return 10 in a`
 
 ℹ Unsafe fix
 132 132 | 
@@ -291,20 +291,20 @@ SIM103.py:135:5: SIM103 [*] Return the condition `not 10 not in a` directly
 135     |-    if 10 not in a:
 136     |-        return False
 137     |-    return True
-    135 |+    return not 10 not in a
+    135 |+    return 10 in a
 138 136 | 
 139 137 | 
 140 138 | def f():
 
-SIM103.py:141:5: SIM103 [*] Return the condition `not a is 10` directly
+SIM103.py:141:5: SIM103 [*] Return the condition `a is not 10` directly
     |
 140 |   def f():
 141 | /     if a is 10:
 142 | |         return False
 143 | |     return True
     | |_______________^ SIM103
     |
-    = help: Replace with `return not a is 10`
+    = help: Replace with `return a is not 10`
 
 ℹ Unsafe fix
 138 138 | 
@@ -313,20 +313,20 @@ SIM103.py:141:5: SIM103 [*] Return the condition `not a is 10` directly
 141     |-    if a is 10:
 142     |-        return False
 143     |-    return True
-    141 |+    return not a is 10
+    141 |+    return a is not 10
 144 142 | 
 145 143 | 
 146 144 | def f():
 
-SIM103.py:147:5: SIM103 [*] Return the condition `not a is not 10` directly
+SIM103.py:147:5: SIM103 [*] Return the condition `a is 10` directly
     |
 146 |   def f():
 147 | /     if a is not 10:
 148 | |         return False
 149 | |     return True
     | |_______________^ SIM103
     |
-    = help: Replace with `return not a is not 10`
+    = help: Replace with `return a is 10`
 
 ℹ Unsafe fix
 144 144 | 
@@ -335,20 +335,20 @@ SIM103.py:147:5: SIM103 [*] Return the condition `not a is not 10` directly
 147     |-    if a is not 10:
 148     |-        return False
 149     |-    return True
-    147 |+    return not a is not 10
+    147 |+    return a is 10
 150 148 | 
 151 149 | 
 152 150 | def f():
 
-SIM103.py:153:5: SIM103 [*] Return the condition `not a == 10` directly
+SIM103.py:153:5: SIM103 [*] Return the condition `a != 10` directly
     |
 152 |   def f():
 153 | /     if a == 10:
 154 | |         return False
 155 | |     return True
     | |_______________^ SIM103
     |
-    = help: Replace with `return not a == 10`
+    = help: Replace with `return a != 10`
 
 ℹ Unsafe fix
 150 150 | 
@@ -357,20 +357,20 @@ SIM103.py:153:5: SIM103 [*] Return the condition `not a == 10` directly
 153     |-    if a == 10:
 154     |-        return False
 155     |-    return True
-    153 |+    return not a == 10
+    153 |+    return a != 10
 156 154 | 
 157 155 | 
 158 156 | def f():
 
-SIM103.py:159:5: SIM103 [*] Return the condition `not a != 10` directly
+SIM103.py:159:5: SIM103 [*] Return the condition `a == 10` directly
     |
 158 |   def f():
 159 | /     if a != 10:
 160 | |         return False
 161 | |     return True
     | |_______________^ SIM103
     |
-    = help: Replace with `return not a != 10`
+    = help: Replace with `return a == 10`
 
 ℹ Unsafe fix
 156 156 | 
@@ -379,4 +379,4 @@ SIM103.py:159:5: SIM103 [*] Return the condition `not a != 10` directly
 159     |-    if a != 10:
 160     |-        return False
 161     |-    return True
-    159 |+    return not a != 10
+    159 |+    return a == 10