Stabilize FURB169 preview behavior (#16666)

## Summary

This PR stabilizes the preview behavior introduced in
#15905

The behavior change is that the rule now also recognizes `type(expr) is
type(None)` comparisons where `expr` isn't a name expression.
For example, the rule now detects `type(a.b) is type(None)` and suggests
rewriting the comparison to `a.b is None`.

The new behavior was introduced with Ruff 0.9.5 (6th of February), about
a month ago. There are no open issues or PRs related to this rule (or
behavior change).

Author: MichaReiser

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

@@ -12,7 +12,6 @@ mod tests {
     use test_case::test_case;
 
     use crate::registry::Rule;
-    use crate::settings::types::PreviewMode;
     use crate::test::test_path;
     use crate::{assert_messages, settings};
 
@@ -62,24 +61,6 @@ mod tests {
         Ok(())
     }
 
-    #[test_case(Rule::TypeNoneComparison, Path::new("FURB169.py"))]
-    fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
-        let snapshot = format!(
-            "preview__{}_{}",
-            rule_code.noqa_code(),
-            path.to_string_lossy()
-        );
-        let diagnostics = test_path(
-            Path::new("refurb").join(path).as_path(),
-            &settings::LinterSettings {
-                preview: PreviewMode::Enabled,
-                ..settings::LinterSettings::for_rule(rule_code)
-            },
-        )?;
-        assert_messages!(snapshot, diagnostics);
-        Ok(())
-    }
-
     #[test]
     fn write_whole_file_python_39() -> Result<()> {
         let diagnostics = test_path(

crates/ruff_linter/src/rules/refurb/rules/type_none_comparison.rs

@@ -13,9 +13,6 @@ use crate::rules::refurb::helpers::replace_with_identity_check;
 /// There is only ever one instance of `None`, so it is more efficient and
 /// readable to use the `is` operator to check if an object is `None`.
 ///
-/// Only name expressions (e.g., `type(foo) == type(None)`) are reported.
-/// In [preview], the rule will also report other kinds of expressions.
-///
 /// ## Example
 /// ```python
 /// type(obj) is type(None)
@@ -34,8 +31,6 @@ use crate::rules::refurb::helpers::replace_with_identity_check;
 /// - [Python documentation: `None`](https://docs.python.org/3/library/constants.html#None)
 /// - [Python documentation: `type`](https://docs.python.org/3/library/functions.html#type)
 /// - [Python documentation: Identity comparisons](https://docs.python.org/3/reference/expressions.html#is-not)
-///
-/// [preview]: https://docs.astral.sh/ruff/preview/
 #[derive(ViolationMetadata)]
 pub(crate) struct TypeNoneComparison {
     replacement: IdentityCheck,
@@ -80,12 +75,6 @@ pub(crate) fn type_none_comparison(checker: &Checker, compare: &ast::ExprCompare
         _ => return,
     };
 
-    if checker.settings.preview.is_disabled()
-        && !matches!(other_arg, Expr::Name(_) | Expr::NoneLiteral(_))
-    {
-        return;
-    }
-
     let diagnostic = Diagnostic::new(TypeNoneComparison { replacement }, compare.range);
 
     let negate = replacement == IdentityCheck::IsNot;

crates/ruff_linter/src/rules/refurb/snapshots/ruff_linter__rules__refurb__tests__FURB169_FURB169.py.snap

@@ -251,4 +251,102 @@ FURB169.py:27:1: FURB169 [*] When checking against `None`, use `is not` instead
    27 |+None is not None
 28 28 | 
 29 29 | type(a.b) is type(None)
-30 30 |
+30 30 | 
+
+FURB169.py:29:1: FURB169 [*] When checking against `None`, use `is` instead of comparison with `type(None)`
+   |
+27 | type(None) != type(None)
+28 |
+29 | type(a.b) is type(None)
+   | ^^^^^^^^^^^^^^^^^^^^^^^ FURB169
+30 |
+31 | type(
+   |
+   = help: Replace with `is None`
+
+ℹ Safe fix
+26 26 | 
+27 27 | type(None) != type(None)
+28 28 | 
+29    |-type(a.b) is type(None)
+   29 |+a.b is None
+30 30 | 
+31 31 | type(
+32 32 |     a(
+
+FURB169.py:31:1: FURB169 [*] When checking against `None`, use `is not` instead of comparison with `type(None)`
+   |
+29 |   type(a.b) is type(None)
+30 |
+31 | / type(
+32 | |     a(
+33 | |         # Comment
+34 | |     )
+35 | | ) != type(None)
+   | |_______________^ FURB169
+36 |
+37 |   type(
+   |
+   = help: Replace with `is not None`
+
+ℹ Unsafe fix
+28 28 | 
+29 29 | type(a.b) is type(None)
+30 30 | 
+31    |-type(
+32    |-    a(
+33    |-        # Comment
+34    |-    )
+35    |-) != type(None)
+   31 |+a() is not None
+36 32 | 
+37 33 | type(
+38 34 |     a := 1
+
+FURB169.py:37:1: FURB169 [*] When checking against `None`, use `is` instead of comparison with `type(None)`
+   |
+35 |   ) != type(None)
+36 |
+37 | / type(
+38 | |     a := 1
+39 | | ) == type(None)
+   | |_______________^ FURB169
+40 |
+41 |   type(
+   |
+   = help: Replace with `is None`
+
+ℹ Safe fix
+34 34 |     )
+35 35 | ) != type(None)
+36 36 | 
+37    |-type(
+38    |-    a := 1
+39    |-) == type(None)
+   37 |+(a := 1) is None
+40 38 | 
+41 39 | type(
+42 40 |     a for a in range(0)
+
+FURB169.py:41:1: FURB169 [*] When checking against `None`, use `is not` instead of comparison with `type(None)`
+   |
+39 |   ) == type(None)
+40 |
+41 | / type(
+42 | |     a for a in range(0)
+43 | | ) is not type(None)
+   | |___________________^ FURB169
+   |
+   = help: Replace with `is not None`
+
+ℹ Safe fix
+38 38 |     a := 1
+39 39 | ) == type(None)
+40 40 | 
+41    |-type(
+42    |-    a for a in range(0)
+43    |-) is not type(None)
+   41 |+(a for a in range(0)) is not None
+44 42 | 
+45 43 | 
+46 44 | # Ok.