[flake8-pyi] Stabilize fix for unused-private-type-var (PYI018) (#16682)

## Summary

This PR stabilizes the fix for `PYI018` introduced in
#15999 (first released with Ruff
0.9.5 early February)

There are no known issues with the fix or open PRs.

Author: MichaReiser

crates/ruff_linter/src/rules/flake8_pyi/mod.rs

@@ -174,8 +174,6 @@ mod tests {
     }
 
     #[test_case(Rule::FutureAnnotationsInStub, Path::new("PYI044.pyi"))]
-    #[test_case(Rule::UnusedPrivateTypeVar, Path::new("PYI018.py"))]
-    #[test_case(Rule::UnusedPrivateTypeVar, Path::new("PYI018.pyi"))]
     fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!(
             "preview__{}_{}",

crates/ruff_linter/src/rules/flake8_pyi/rules/unused_private_type_definition.rs

@@ -26,9 +26,8 @@ use crate::fix;
 /// _Ts = typing_extensions.TypeVarTuple("_Ts")
 /// ```
 ///
-/// ## Fix safety and availability
-/// This rule's fix is available when [`preview`] mode is enabled.
-/// It is always marked as unsafe, as it would break your code if the type
+/// ## Fix safety
+/// The fix is always marked as unsafe, as it would break your code if the type
 /// variable is imported by another module.
 #[derive(ViolationMetadata)]
 pub(crate) struct UnusedPrivateTypeVar {
@@ -225,18 +224,19 @@ pub(crate) fn unused_private_type_var(checker: &Checker, scope: &Scope) {
             continue;
         };
 
-        let mut diagnostic = Diagnostic::new(
+        let diagnostic = Diagnostic::new(
             UnusedPrivateTypeVar {
                 type_var_like_name: id.to_string(),
                 type_var_like_kind: type_var_like_kind.to_string(),
             },
             binding.range(),
-        );
-
-        if checker.settings.preview.is_enabled() {
-            let edit = fix::edits::delete_stmt(stmt, None, checker.locator(), checker.indexer());
-            diagnostic.set_fix(Fix::unsafe_edit(edit));
-        }
+        )
+        .with_fix(Fix::unsafe_edit(fix::edits::delete_stmt(
+            stmt,
+            None,
+            checker.locator(),
+            checker.indexer(),
+        )));
 
         checker.report_diagnostic(diagnostic);
     }

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__PYI018_PYI018.py.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_pyi/mod.rs
 ---
-PYI018.py:6:1: PYI018 Private TypeVar `_T` is never used
+PYI018.py:6:1: PYI018 [*] Private TypeVar `_T` is never used
   |
 4 | from typing_extensions import ParamSpec, TypeVarTuple
 5 |
@@ -12,7 +12,16 @@ PYI018.py:6:1: PYI018 Private TypeVar `_T` is never used
   |
   = help: Remove unused private TypeVar `_T`
 
-PYI018.py:7:1: PYI018 Private TypeVarTuple `_Ts` is never used
+ℹ Unsafe fix
+3 3 | from typing import TypeVar
+4 4 | from typing_extensions import ParamSpec, TypeVarTuple
+5 5 | 
+6   |-_T = typing.TypeVar("_T")
+7 6 | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8 7 | _P = ParamSpec("_P")
+9 8 | _P2 = typing.ParamSpec("_P2")
+
+PYI018.py:7:1: PYI018 [*] Private TypeVarTuple `_Ts` is never used
   |
 6 | _T = typing.TypeVar("_T")
 7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
@@ -22,7 +31,16 @@ PYI018.py:7:1: PYI018 Private TypeVarTuple `_Ts` is never used
   |
   = help: Remove unused private TypeVarTuple `_Ts`
 
-PYI018.py:8:1: PYI018 Private ParamSpec `_P` is never used
+ℹ Unsafe fix
+4 4 | from typing_extensions import ParamSpec, TypeVarTuple
+5 5 | 
+6 6 | _T = typing.TypeVar("_T")
+7   |-_Ts = typing_extensions.TypeVarTuple("_Ts")
+8 7 | _P = ParamSpec("_P")
+9 8 | _P2 = typing.ParamSpec("_P2")
+10 9 | _Ts2 = TypeVarTuple("_Ts2")
+
+PYI018.py:8:1: PYI018 [*] Private ParamSpec `_P` is never used
    |
  6 | _T = typing.TypeVar("_T")
  7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
@@ -33,7 +51,16 @@ PYI018.py:8:1: PYI018 Private ParamSpec `_P` is never used
    |
    = help: Remove unused private ParamSpec `_P`
 
-PYI018.py:9:1: PYI018 Private ParamSpec `_P2` is never used
+ℹ Unsafe fix
+5 5 | 
+6 6 | _T = typing.TypeVar("_T")
+7 7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8   |-_P = ParamSpec("_P")
+9 8 | _P2 = typing.ParamSpec("_P2")
+10 9 | _Ts2 = TypeVarTuple("_Ts2")
+11 10 | 
+
+PYI018.py:9:1: PYI018 [*] Private ParamSpec `_P2` is never used
    |
  7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
  8 | _P = ParamSpec("_P")
@@ -43,7 +70,16 @@ PYI018.py:9:1: PYI018 Private ParamSpec `_P2` is never used
    |
    = help: Remove unused private ParamSpec `_P2`
 
-PYI018.py:10:1: PYI018 Private TypeVarTuple `_Ts2` is never used
+ℹ Unsafe fix
+6  6  | _T = typing.TypeVar("_T")
+7  7  | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8  8  | _P = ParamSpec("_P")
+9     |-_P2 = typing.ParamSpec("_P2")
+10 9  | _Ts2 = TypeVarTuple("_Ts2")
+11 10 | 
+12 11 | # OK
+
+PYI018.py:10:1: PYI018 [*] Private TypeVarTuple `_Ts2` is never used
    |
  8 | _P = ParamSpec("_P")
  9 | _P2 = typing.ParamSpec("_P2")
@@ -53,3 +89,12 @@ PYI018.py:10:1: PYI018 Private TypeVarTuple `_Ts2` is never used
 12 | # OK
    |
    = help: Remove unused private TypeVarTuple `_Ts2`
+
+ℹ Unsafe fix
+7  7  | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8  8  | _P = ParamSpec("_P")
+9  9  | _P2 = typing.ParamSpec("_P2")
+10    |-_Ts2 = TypeVarTuple("_Ts2")
+11 10 | 
+12 11 | # OK
+13 12 | _UsedTypeVar = TypeVar("_UsedTypeVar")

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__PYI018_PYI018.pyi.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_pyi/mod.rs
 ---
-PYI018.pyi:6:1: PYI018 Private TypeVar `_T` is never used
+PYI018.pyi:6:1: PYI018 [*] Private TypeVar `_T` is never used
   |
 4 | from typing_extensions import ParamSpec, TypeVarTuple
 5 |
@@ -12,7 +12,16 @@ PYI018.pyi:6:1: PYI018 Private TypeVar `_T` is never used
   |
   = help: Remove unused private TypeVar `_T`
 
-PYI018.pyi:7:1: PYI018 Private TypeVarTuple `_Ts` is never used
+ℹ Unsafe fix
+3 3 | from typing import TypeVar
+4 4 | from typing_extensions import ParamSpec, TypeVarTuple
+5 5 | 
+6   |-_T = typing.TypeVar("_T")
+7 6 | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8 7 | _P = ParamSpec("_P")
+9 8 | _P2 = typing.ParamSpec("_P2")
+
+PYI018.pyi:7:1: PYI018 [*] Private TypeVarTuple `_Ts` is never used
   |
 6 | _T = typing.TypeVar("_T")
 7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
@@ -22,7 +31,16 @@ PYI018.pyi:7:1: PYI018 Private TypeVarTuple `_Ts` is never used
   |
   = help: Remove unused private TypeVarTuple `_Ts`
 
-PYI018.pyi:8:1: PYI018 Private ParamSpec `_P` is never used
+ℹ Unsafe fix
+4 4 | from typing_extensions import ParamSpec, TypeVarTuple
+5 5 | 
+6 6 | _T = typing.TypeVar("_T")
+7   |-_Ts = typing_extensions.TypeVarTuple("_Ts")
+8 7 | _P = ParamSpec("_P")
+9 8 | _P2 = typing.ParamSpec("_P2")
+10 9 | _Ts2 = TypeVarTuple("_Ts2")
+
+PYI018.pyi:8:1: PYI018 [*] Private ParamSpec `_P` is never used
    |
  6 | _T = typing.TypeVar("_T")
  7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
@@ -33,7 +51,16 @@ PYI018.pyi:8:1: PYI018 Private ParamSpec `_P` is never used
    |
    = help: Remove unused private ParamSpec `_P`
 
-PYI018.pyi:9:1: PYI018 Private ParamSpec `_P2` is never used
+ℹ Unsafe fix
+5 5 | 
+6 6 | _T = typing.TypeVar("_T")
+7 7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8   |-_P = ParamSpec("_P")
+9 8 | _P2 = typing.ParamSpec("_P2")
+10 9 | _Ts2 = TypeVarTuple("_Ts2")
+11 10 | 
+
+PYI018.pyi:9:1: PYI018 [*] Private ParamSpec `_P2` is never used
    |
  7 | _Ts = typing_extensions.TypeVarTuple("_Ts")
  8 | _P = ParamSpec("_P")
@@ -43,7 +70,16 @@ PYI018.pyi:9:1: PYI018 Private ParamSpec `_P2` is never used
    |
    = help: Remove unused private ParamSpec `_P2`
 
-PYI018.pyi:10:1: PYI018 Private TypeVarTuple `_Ts2` is never used
+ℹ Unsafe fix
+6  6  | _T = typing.TypeVar("_T")
+7  7  | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8  8  | _P = ParamSpec("_P")
+9     |-_P2 = typing.ParamSpec("_P2")
+10 9  | _Ts2 = TypeVarTuple("_Ts2")
+11 10 | 
+12 11 | # OK
+
+PYI018.pyi:10:1: PYI018 [*] Private TypeVarTuple `_Ts2` is never used
    |
  8 | _P = ParamSpec("_P")
  9 | _P2 = typing.ParamSpec("_P2")
@@ -53,3 +89,12 @@ PYI018.pyi:10:1: PYI018 Private TypeVarTuple `_Ts2` is never used
 12 | # OK
    |
    = help: Remove unused private TypeVarTuple `_Ts2`
+
+ℹ Unsafe fix
+7  7  | _Ts = typing_extensions.TypeVarTuple("_Ts")
+8  8  | _P = ParamSpec("_P")
+9  9  | _P2 = typing.ParamSpec("_P2")
+10    |-_Ts2 = TypeVarTuple("_Ts2")
+11 10 | 
+12 11 | # OK
+13 12 | _UsedTypeVar = TypeVar("_UsedTypeVar")