[pyupgrade] Split UP007 to two individual rules for Union and Optional (UP007, UP045) (#15313)

Co-authored-by: Micha Reiser <micha@reiser.io>

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP007.py

@@ -1,16 +1,7 @@
 import typing
-from typing import Optional
 from typing import Union
 
 
-def f(x: Optional[str]) -> None:
-    ...
-
-
-def f(x: typing.Optional[str]) -> None:
-    ...
-
-
 def f(x: Union[str, int, Union[float, bytes]]) -> None:
     ...
 
@@ -52,9 +43,6 @@ def f(x: Union[("str", "int"), float]) -> None:
 
 
 def f() -> None:
-    x: Optional[str]
-    x = Optional[str]
-
     x = Union[str, int]
     x = Union["str", "int"]
     x: Union[str, int]
@@ -85,31 +73,6 @@ def f(x: Union[str, lambda: int]) -> None:
     ...
 
 
-def f(x: Optional[int : float]) -> None:
-    ...
-
-
-def f(x: Optional[str, int : float]) -> None:
-    ...
-
-
-def f(x: Optional[int, float]) -> None:
-    ...
-
-
-# Regression test for: https://github.com/astral-sh/ruff/issues/7131
-class ServiceRefOrValue:
-    service_specification: Optional[
-        list[ServiceSpecificationRef]
-        | list[ServiceSpecification]
-    ] = None
-
-
-# Regression test for: https://github.com/astral-sh/ruff/issues/7201
-class ServiceRefOrValue:
-    service_specification: Optional[str]is not True = None
-
-
 # Regression test for: https://github.com/astral-sh/ruff/issues/7452
 class Collection(Protocol[*_B0]):
     def __iter__(self) -> Iterator[Union[*_B0]]:

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP045.py

@@ -0,0 +1,44 @@
+import typing
+from typing import Optional
+
+
+def f(x: Optional[str]) -> None:
+    ...
+
+
+def f(x: typing.Optional[str]) -> None:
+    ...
+
+
+def f() -> None:
+    x: Optional[str]
+    x = Optional[str]
+
+
+def f(x: list[Optional[int]]) -> None:
+    ...
+
+
+def f(x: Optional[int : float]) -> None:
+    ...
+
+
+def f(x: Optional[str, int : float]) -> None:
+    ...
+
+
+def f(x: Optional[int, float]) -> None:
+    ...
+
+
+# Regression test for: https://github.com/astral-sh/ruff/issues/7131
+class ServiceRefOrValue:
+    service_specification: Optional[
+        list[ServiceSpecificationRef]
+        | list[ServiceSpecification]
+    ] = None
+
+
+# Regression test for: https://github.com/astral-sh/ruff/issues/7201
+class ServiceRefOrValue:
+    service_specification: Optional[str]is not True = None

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -27,7 +27,8 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             // Ex) Optional[...], Union[...]
             if checker.any_enabled(&[
                 Rule::FutureRewritableTypeAnnotation,
-                Rule::NonPEP604Annotation,
+                Rule::NonPEP604AnnotationUnion,
+                Rule::NonPEP604AnnotationOptional,
             ]) {
                 if let Some(operator) = typing::to_pep604_operator(value, slice, &checker.semantic)
                 {
@@ -43,7 +44,10 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
                             );
                         }
                     }
-                    if checker.enabled(Rule::NonPEP604Annotation) {
+                    if checker.any_enabled(&[
+                        Rule::NonPEP604AnnotationUnion,
+                        Rule::NonPEP604AnnotationOptional,
+                    ]) {
                         if checker.source_type.is_stub()
                             || checker.settings.target_version >= PythonVersion::Py310
                             || (checker.settings.target_version >= PythonVersion::Py37
@@ -51,7 +55,7 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
                                 && checker.semantic.in_annotation()
                                 && !checker.settings.pyupgrade.keep_runtime_typing)
                         {
-                            pyupgrade::rules::use_pep604_annotation(checker, expr, slice, operator);
+                            pyupgrade::rules::non_pep604_annotation(checker, expr, slice, operator);
                         }
                     }
                 }

crates/ruff_linter/src/codes.rs

@@ -501,7 +501,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pyupgrade, "004") => (RuleGroup::Stable, rules::pyupgrade::rules::UselessObjectInheritance),
         (Pyupgrade, "005") => (RuleGroup::Stable, rules::pyupgrade::rules::DeprecatedUnittestAlias),
         (Pyupgrade, "006") => (RuleGroup::Stable, rules::pyupgrade::rules::NonPEP585Annotation),
-        (Pyupgrade, "007") => (RuleGroup::Stable, rules::pyupgrade::rules::NonPEP604Annotation),
+        (Pyupgrade, "007") => (RuleGroup::Stable, rules::pyupgrade::rules::NonPEP604AnnotationUnion),
         (Pyupgrade, "008") => (RuleGroup::Stable, rules::pyupgrade::rules::SuperCallWithParameters),
         (Pyupgrade, "009") => (RuleGroup::Stable, rules::pyupgrade::rules::UTF8EncodingDeclaration),
         (Pyupgrade, "010") => (RuleGroup::Stable, rules::pyupgrade::rules::UnnecessaryFutureImport),
@@ -538,6 +538,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pyupgrade, "042") => (RuleGroup::Preview, rules::pyupgrade::rules::ReplaceStrEnum),
         (Pyupgrade, "043") => (RuleGroup::Stable, rules::pyupgrade::rules::UnnecessaryDefaultTypeArgs),
         (Pyupgrade, "044") => (RuleGroup::Preview, rules::pyupgrade::rules::NonPEP646Unpack),
+        (Pyupgrade, "045") => (RuleGroup::Preview, rules::pyupgrade::rules::NonPEP604AnnotationOptional),
 
         // pydocstyle
         (Pydocstyle, "100") => (RuleGroup::Stable, rules::pydocstyle::rules::UndocumentedPublicModule),

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

@@ -39,7 +39,8 @@ mod tests {
     #[test_case(Rule::NonPEP585Annotation, Path::new("UP006_1.py"))]
     #[test_case(Rule::NonPEP585Annotation, Path::new("UP006_2.py"))]
     #[test_case(Rule::NonPEP585Annotation, Path::new("UP006_3.py"))]
-    #[test_case(Rule::NonPEP604Annotation, Path::new("UP007.py"))]
+    #[test_case(Rule::NonPEP604AnnotationUnion, Path::new("UP007.py"))]
+    #[test_case(Rule::NonPEP604AnnotationUnion, Path::new("UP045.py"))]
     #[test_case(Rule::NonPEP604Isinstance, Path::new("UP038.py"))]
     #[test_case(Rule::OSErrorAlias, Path::new("UP024_0.py"))]
     #[test_case(Rule::OSErrorAlias, Path::new("UP024_1.py"))]
@@ -111,6 +112,19 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn up007_preview() -> Result<()> {
+        let diagnostics = test_path(
+            Path::new("pyupgrade/UP045.py"),
+            &settings::LinterSettings {
+                preview: PreviewMode::Enabled,
+                ..settings::LinterSettings::for_rule(Rule::NonPEP604AnnotationUnion)
+            },
+        )?;
+        assert_messages!(diagnostics);
+        Ok(())
+    }
+
     #[test]
     fn async_timeout_error_alias_not_applied_py310() -> Result<()> {
         let diagnostics = test_path(
@@ -201,7 +215,10 @@ mod tests {
             Path::new("pyupgrade/future_annotations.py"),
             &settings::LinterSettings {
                 target_version: PythonVersion::Py37,
-                ..settings::LinterSettings::for_rule(Rule::NonPEP604Annotation)
+                ..settings::LinterSettings::for_rules([
+                    Rule::NonPEP604AnnotationUnion,
+                    Rule::NonPEP604AnnotationOptional,
+                ])
             },
         )?;
         assert_messages!(diagnostics);
@@ -214,7 +231,10 @@ mod tests {
             Path::new("pyupgrade/future_annotations.py"),
             &settings::LinterSettings {
                 target_version: PythonVersion::Py310,
-                ..settings::LinterSettings::for_rule(Rule::NonPEP604Annotation)
+                ..settings::LinterSettings::for_rules([
+                    Rule::NonPEP604AnnotationUnion,
+                    Rule::NonPEP604AnnotationOptional,
+                ])
             },
         )?;
         assert_messages!(diagnostics);

crates/ruff_linter/src/rules/pyupgrade/rules/use_pep604_annotation.rs

@@ -1,4 +1,6 @@
-use ruff_diagnostics::{Applicability, Diagnostic, Edit, Fix, FixAvailability, Violation};
+use ruff_diagnostics::{
+    Applicability, Diagnostic, DiagnosticKind, Edit, Fix, FixAvailability, Violation,
+};
 use ruff_macros::{derive_message_formats, ViolationMetadata};
 use ruff_python_ast::helpers::{pep_604_optional, pep_604_union};
 use ruff_python_ast::{self as ast, Expr};
@@ -6,8 +8,9 @@ use ruff_python_semantic::analyze::typing::Pep604Operator;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
+use crate::codes::Rule;
 use crate::fix::edits::pad;
-use crate::settings::types::PythonVersion;
+use crate::settings::types::{PreviewMode, PythonVersion};
 
 /// ## What it does
 /// Check for type annotations that can be rewritten based on [PEP 604] syntax.
@@ -37,6 +40,10 @@ use crate::settings::types::PythonVersion;
 /// foo: int | str = 1
 /// ```
 ///
+/// ## Preview
+/// In preview mode, this rule only checks for usages of `typing.Union`,
+/// while `UP045` checks for `typing.Optional`.
+///
 /// ## Fix safety
 /// This rule's fix is marked as unsafe, as it may lead to runtime errors when
 /// alongside libraries that rely on runtime type annotations, like Pydantic,
@@ -50,9 +57,9 @@ use crate::settings::types::PythonVersion;
 ///
 /// [PEP 604]: https://peps.python.org/pep-0604/
 #[derive(ViolationMetadata)]
-pub(crate) struct NonPEP604Annotation;
+pub(crate) struct NonPEP604AnnotationUnion;
 
-impl Violation for NonPEP604Annotation {
+impl Violation for NonPEP604AnnotationUnion {
     const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
 
     #[derive_message_formats]
@@ -65,8 +72,64 @@ impl Violation for NonPEP604Annotation {
     }
 }
 
-/// UP007
+/// ## What it does
-pub(crate) fn use_pep604_annotation(
+/// Check for `typing.Optional` annotations that can be rewritten based on [PEP 604] syntax.
+///
+/// ## Why is this bad?
+/// [PEP 604] introduced a new syntax for union type annotations based on the
+/// `|` operator. This syntax is more concise and readable than the previous
+/// `typing.Optional` syntax.
+///
+/// This rule is enabled when targeting Python 3.10 or later (see:
+/// [`target-version`]). By default, it's _also_ enabled for earlier Python
+/// versions if `from __future__ import annotations` is present, as
+/// `__future__` annotations are not evaluated at runtime. If your code relies
+/// on runtime type annotations (either directly or via a library like
+/// Pydantic), you can disable this behavior for Python versions prior to 3.10
+/// by setting [`lint.pyupgrade.keep-runtime-typing`] to `true`.
+///
+/// ## Example
+/// ```python
+/// from typing import Optional
+///
+/// foo: Optional[int] = None
+/// ```
+///
+/// Use instead:
+/// ```python
+/// foo: int | None = None
+/// ```
+///
+/// ## Fix safety
+/// This rule's fix is marked as unsafe, as it may lead to runtime errors when
+/// alongside libraries that rely on runtime type annotations, like Pydantic,
+/// on Python versions prior to Python 3.10. It may also lead to runtime errors
+/// in unusual and likely incorrect type annotations where the type does not
+/// support the `|` operator.
+///
+/// ## Options
+/// - `target-version`
+/// - `lint.pyupgrade.keep-runtime-typing`
+///
+/// [PEP 604]: https://peps.python.org/pep-0604/
+#[derive(ViolationMetadata)]
+pub(crate) struct NonPEP604AnnotationOptional;
+
+impl Violation for NonPEP604AnnotationOptional {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "Use `X | None` for type annotations".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Convert to `X | None`".to_string())
+    }
+}
+
+/// UP007, UP045
+pub(crate) fn non_pep604_annotation(
     checker: &mut Checker,
     expr: &Expr,
     slice: &Expr,
@@ -86,7 +149,23 @@ pub(crate) fn use_pep604_annotation(
 
     match operator {
         Pep604Operator::Optional => {
-            let mut diagnostic = Diagnostic::new(NonPEP604Annotation, expr.range());
+            let (rule, diagnostic_kind) = match checker.settings.preview {
+                PreviewMode::Disabled => (
+                    Rule::NonPEP604AnnotationUnion,
+                    DiagnosticKind::from(NonPEP604AnnotationUnion),
+                ),
+                PreviewMode::Enabled => (
+                    Rule::NonPEP604AnnotationOptional,
+                    DiagnosticKind::from(NonPEP604AnnotationOptional),
+                ),
+            };
+
+            if !checker.enabled(rule) {
+                return;
+            }
+
+            let mut diagnostic = Diagnostic::new(diagnostic_kind, expr.range());
+
             if fixable {
                 match slice {
                     Expr::Tuple(_) => {
@@ -110,7 +189,11 @@ pub(crate) fn use_pep604_annotation(
             checker.diagnostics.push(diagnostic);
         }
         Pep604Operator::Union => {
-            let mut diagnostic = Diagnostic::new(NonPEP604Annotation, expr.range());
+            if !checker.enabled(Rule::NonPEP604AnnotationUnion) {
+                return;
+            }
+
+            let mut diagnostic = Diagnostic::new(NonPEP604AnnotationUnion, expr.range());
             if fixable {
                 match slice {
                     Expr::Slice(_) => {

crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP007.py.snap

@@ -2,432 +2,296 @@
 source: crates/ruff_linter/src/rules/pyupgrade/mod.rs
 snapshot_kind: text
 ---
-UP007.py:6:10: UP007 [*] Use `X | Y` for type annotations
+UP007.py:5:10: UP007 [*] Use `X | Y` for type annotations
   |
-6 | def f(x: Optional[str]) -> None:
+5 | def f(x: Union[str, int, Union[float, bytes]]) -> None:
-  |          ^^^^^^^^^^^^^ UP007
+  |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UP007
-7 |     ...
+6 |     ...
   |
   = help: Convert to `X | Y`
 
 ℹ Safe fix
-3 3 | from typing import Union
+2 2 | from typing import Union
+3 3 | 
 4 4 | 
-5 5 | 
+5   |-def f(x: Union[str, int, Union[float, bytes]]) -> None:
-6   |-def f(x: Optional[str]) -> None:
+  5 |+def f(x: str | int | Union[float, bytes]) -> None:
-  6 |+def f(x: str | None) -> None:
+6 6 |     ...
-7 7 |     ...
+7 7 | 
 8 8 | 
-9 9 | 
 
-UP007.py:10:10: UP007 [*] Use `X | Y` for type annotations
+UP007.py:5:26: UP007 [*] Use `X | Y` for type annotations
-   |
+  |
-10 | def f(x: typing.Optional[str]) -> None:
+5 | def f(x: Union[str, int, Union[float, bytes]]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^^^ UP007
+  |                          ^^^^^^^^^^^^^^^^^^^ UP007
-11 |     ...
+6 |     ...
-   |
+  |
-   = help: Convert to `X | Y`
+  = help: Convert to `X | Y`
 
 ℹ Safe fix
-7  7  |     ...
+2 2 | from typing import Union
-8  8  | 
+3 3 | 
-9  9  | 
+4 4 | 
-10    |-def f(x: typing.Optional[str]) -> None:
+5   |-def f(x: Union[str, int, Union[float, bytes]]) -> None:
-   10 |+def f(x: str | None) -> None:
+  5 |+def f(x: Union[str, int, float | bytes]) -> None:
-11 11 |     ...
+6 6 |     ...
-12 12 | 
+7 7 | 
-13 13 | 
+8 8 | 
 
-UP007.py:14:10: UP007 [*] Use `X | Y` for type annotations
+UP007.py:9:10: UP007 [*] Use `X | Y` for type annotations
    |
-14 | def f(x: Union[str, int, Union[float, bytes]]) -> None:
+ 9 | def f(x: typing.Union[str, int]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UP007
-15 |     ...
-   |
-   = help: Convert to `X | Y`
-
-ℹ Safe fix
-11 11 |     ...
-12 12 | 
-13 13 | 
-14    |-def f(x: Union[str, int, Union[float, bytes]]) -> None:
-   14 |+def f(x: str | int | Union[float, bytes]) -> None:
-15 15 |     ...
-16 16 | 
-17 17 | 
-
-UP007.py:14:26: UP007 [*] Use `X | Y` for type annotations
-   |
-14 | def f(x: Union[str, int, Union[float, bytes]]) -> None:
-   |                          ^^^^^^^^^^^^^^^^^^^ UP007
-15 |     ...
-   |
-   = help: Convert to `X | Y`
-
-ℹ Safe fix
-11 11 |     ...
-12 12 | 
-13 13 | 
-14    |-def f(x: Union[str, int, Union[float, bytes]]) -> None:
-   14 |+def f(x: Union[str, int, float | bytes]) -> None:
-15 15 |     ...
-16 16 | 
-17 17 | 
-
-UP007.py:18:10: UP007 [*] Use `X | Y` for type annotations
-   |
-18 | def f(x: typing.Union[str, int]) -> None:
    |          ^^^^^^^^^^^^^^^^^^^^^^ UP007
-19 |     ...
+10 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-15 15 |     ...
+6  6  |     ...
-16 16 | 
+7  7  | 
-17 17 | 
+8  8  | 
-18    |-def f(x: typing.Union[str, int]) -> None:
+9     |-def f(x: typing.Union[str, int]) -> None:
-   18 |+def f(x: str | int) -> None:
+   9  |+def f(x: str | int) -> None:
-19 19 |     ...
+10 10 |     ...
-20 20 | 
+11 11 | 
-21 21 | 
+12 12 | 
 
-UP007.py:22:10: UP007 [*] Use `X | Y` for type annotations
+UP007.py:13:10: UP007 [*] Use `X | Y` for type annotations
    |
-22 | def f(x: typing.Union[(str, int)]) -> None:
+13 | def f(x: typing.Union[(str, int)]) -> None:
    |          ^^^^^^^^^^^^^^^^^^^^^^^^ UP007
-23 |     ...
+14 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-19 19 |     ...
+10 10 |     ...
-20 20 | 
+11 11 | 
-21 21 | 
+12 12 | 
-22    |-def f(x: typing.Union[(str, int)]) -> None:
+13    |-def f(x: typing.Union[(str, int)]) -> None:
-   22 |+def f(x: str | int) -> None:
+   13 |+def f(x: str | int) -> None:
-23 23 |     ...
+14 14 |     ...
-24 24 | 
+15 15 | 
-25 25 | 
+16 16 | 
 
-UP007.py:26:10: UP007 [*] Use `X | Y` for type annotations
+UP007.py:17:10: UP007 [*] Use `X | Y` for type annotations
    |
-26 | def f(x: typing.Union[(str, int), float]) -> None:
+17 | def f(x: typing.Union[(str, int), float]) -> None:
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UP007
-27 |     ...
+18 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-23 23 |     ...
+14 14 |     ...
-24 24 | 
+15 15 | 
-25 25 | 
+16 16 | 
-26    |-def f(x: typing.Union[(str, int), float]) -> None:
+17    |-def f(x: typing.Union[(str, int), float]) -> None:
-   26 |+def f(x: str | int | float) -> None:
+   17 |+def f(x: str | int | float) -> None:
-27 27 |     ...
+18 18 |     ...
-28 28 | 
+19 19 | 
-29 29 | 
+20 20 | 
 
-UP007.py:30:10: UP007 [*] Use `X | Y` for type annotations
+UP007.py:21:10: UP007 [*] Use `X | Y` for type annotations
    |
-30 | def f(x: typing.Union[(int,)]) -> None:
+21 | def f(x: typing.Union[(int,)]) -> None:
    |          ^^^^^^^^^^^^^^^^^^^^ UP007
-31 |     ...
+22 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-27 27 |     ...
+18 18 |     ...
-28 28 | 
+19 19 | 
-29 29 | 
+20 20 | 
-30    |-def f(x: typing.Union[(int,)]) -> None:
+21    |-def f(x: typing.Union[(int,)]) -> None:
-   30 |+def f(x: int) -> None:
+   21 |+def f(x: int) -> None:
-31 31 |     ...
+22 22 |     ...
-32 32 | 
+23 23 | 
-33 33 | 
+24 24 | 
 
-UP007.py:34:10: UP007 [*] Use `X | Y` for type annotations
+UP007.py:25:10: UP007 [*] Use `X | Y` for type annotations
    |
-34 | def f(x: typing.Union[()]) -> None:
+25 | def f(x: typing.Union[()]) -> None:
    |          ^^^^^^^^^^^^^^^^ UP007
-35 |     ...
+26 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-31 31 |     ...
+22 22 |     ...
-32 32 | 
+23 23 | 
-33 33 | 
+24 24 | 
-34    |-def f(x: typing.Union[()]) -> None:
+25    |-def f(x: typing.Union[()]) -> None:
-   34 |+def f(x: ()) -> None:
+   25 |+def f(x: ()) -> None:
-35 35 |     ...
+26 26 |     ...
-36 36 | 
+27 27 | 
-37 37 | 
+28 28 | 
 
-UP007.py:38:11: UP007 [*] Use `X | Y` for type annotations
+UP007.py:29:11: UP007 [*] Use `X | Y` for type annotations
    |
-38 | def f(x: "Union[str, int, Union[float, bytes]]") -> None:
+29 | def f(x: "Union[str, int, Union[float, bytes]]") -> None:
    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UP007
-39 |     ...
+30 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-35 35 |     ...
+26 26 |     ...
-36 36 | 
+27 27 | 
-37 37 | 
+28 28 | 
-38    |-def f(x: "Union[str, int, Union[float, bytes]]") -> None:
+29    |-def f(x: "Union[str, int, Union[float, bytes]]") -> None:
-   38 |+def f(x: "str | int | Union[float, bytes]") -> None:
+   29 |+def f(x: "str | int | Union[float, bytes]") -> None:
-39 39 |     ...
+30 30 |     ...
-40 40 | 
+31 31 | 
-41 41 | 
+32 32 | 
 
-UP007.py:38:27: UP007 [*] Use `X | Y` for type annotations
+UP007.py:29:27: UP007 [*] Use `X | Y` for type annotations
    |
-38 | def f(x: "Union[str, int, Union[float, bytes]]") -> None:
+29 | def f(x: "Union[str, int, Union[float, bytes]]") -> None:
    |                           ^^^^^^^^^^^^^^^^^^^ UP007
-39 |     ...
+30 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-35 35 |     ...
+26 26 |     ...
-36 36 | 
+27 27 | 
-37 37 | 
+28 28 | 
-38    |-def f(x: "Union[str, int, Union[float, bytes]]") -> None:
+29    |-def f(x: "Union[str, int, Union[float, bytes]]") -> None:
-   38 |+def f(x: "Union[str, int, float | bytes]") -> None:
+   29 |+def f(x: "Union[str, int, float | bytes]") -> None:
-39 39 |     ...
+30 30 |     ...
-40 40 | 
+31 31 | 
-41 41 | 
+32 32 | 
 
-UP007.py:42:11: UP007 [*] Use `X | Y` for type annotations
+UP007.py:33:11: UP007 [*] Use `X | Y` for type annotations
    |
-42 | def f(x: "typing.Union[str, int]") -> None:
+33 | def f(x: "typing.Union[str, int]") -> None:
    |           ^^^^^^^^^^^^^^^^^^^^^^ UP007
-43 |     ...
+34 |     ...
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-39 39 |     ...
+30 30 |     ...
-40 40 | 
+31 31 | 
-41 41 | 
+32 32 | 
-42    |-def f(x: "typing.Union[str, int]") -> None:
+33    |-def f(x: "typing.Union[str, int]") -> None:
-   42 |+def f(x: "str | int") -> None:
+   33 |+def f(x: "str | int") -> None:
-43 43 |     ...
+34 34 |     ...
-44 44 | 
+35 35 | 
-45 45 | 
+36 36 | 
 
-UP007.py:55:8: UP007 [*] Use `X | Y` for type annotations
+UP007.py:46:9: UP007 Use `X | Y` for type annotations
    |
-54 | def f() -> None:
+45 | def f() -> None:
-55 |     x: Optional[str]
+46 |     x = Union[str, int]
-   |        ^^^^^^^^^^^^^ UP007
-56 |     x = Optional[str]
-   |
-   = help: Convert to `X | Y`
-
-ℹ Safe fix
-52 52 | 
-53 53 | 
-54 54 | def f() -> None:
-55    |-    x: Optional[str]
-   55 |+    x: str | None
-56 56 |     x = Optional[str]
-57 57 | 
-58 58 |     x = Union[str, int]
-
-UP007.py:56:9: UP007 Use `X | Y` for type annotations
-   |
-54 | def f() -> None:
-55 |     x: Optional[str]
-56 |     x = Optional[str]
-   |         ^^^^^^^^^^^^^ UP007
-57 | 
-58 |     x = Union[str, int]
-   |
-   = help: Convert to `X | Y`
-
-UP007.py:58:9: UP007 Use `X | Y` for type annotations
-   |
-56 |     x = Optional[str]
-57 | 
-58 |     x = Union[str, int]
    |         ^^^^^^^^^^^^^^^ UP007
-59 |     x = Union["str", "int"]
+47 |     x = Union["str", "int"]
-60 |     x: Union[str, int]
+48 |     x: Union[str, int]
    |
    = help: Convert to `X | Y`
 
-UP007.py:60:8: UP007 [*] Use `X | Y` for type annotations
+UP007.py:48:8: UP007 [*] Use `X | Y` for type annotations
    |
-58 |     x = Union[str, int]
+46 |     x = Union[str, int]
-59 |     x = Union["str", "int"]
+47 |     x = Union["str", "int"]
-60 |     x: Union[str, int]
+48 |     x: Union[str, int]
    |        ^^^^^^^^^^^^^^^ UP007
-61 |     x: Union["str", "int"]
+49 |     x: Union["str", "int"]
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-57 57 | 
+45 45 | def f() -> None:
-58 58 |     x = Union[str, int]
+46 46 |     x = Union[str, int]
-59 59 |     x = Union["str", "int"]
+47 47 |     x = Union["str", "int"]
-60    |-    x: Union[str, int]
+48    |-    x: Union[str, int]
-   60 |+    x: str | int
+   48 |+    x: str | int
-61 61 |     x: Union["str", "int"]
+49 49 |     x: Union["str", "int"]
-62 62 | 
+50 50 | 
-63 63 | 
+51 51 | 
 
-UP007.py:61:8: UP007 [*] Use `X | Y` for type annotations
+UP007.py:49:8: UP007 [*] Use `X | Y` for type annotations
    |
-59 |     x = Union["str", "int"]
+47 |     x = Union["str", "int"]
-60 |     x: Union[str, int]
+48 |     x: Union[str, int]
-61 |     x: Union["str", "int"]
+49 |     x: Union["str", "int"]
    |        ^^^^^^^^^^^^^^^^^^^ UP007
    |
    = help: Convert to `X | Y`
 
 ℹ Safe fix
-58 58 |     x = Union[str, int]
+46 46 |     x = Union[str, int]
-59 59 |     x = Union["str", "int"]
+47 47 |     x = Union["str", "int"]
-60 60 |     x: Union[str, int]
+48 48 |     x: Union[str, int]
-61    |-    x: Union["str", "int"]
+49    |-    x: Union["str", "int"]
-   61 |+    x: "str" | "int"
+   49 |+    x: "str" | "int"
-62 62 | 
+50 50 | 
-63 63 | 
+51 51 | 
-64 64 | def f(x: Union[int : float]) -> None:
+52 52 | def f(x: Union[int : float]) -> None:
+
+UP007.py:52:10: UP007 Use `X | Y` for type annotations
+   |
+52 | def f(x: Union[int : float]) -> None:
+   |          ^^^^^^^^^^^^^^^^^^ UP007
+53 |     ...
+   |
+   = help: Convert to `X | Y`
+
+UP007.py:56:10: UP007 Use `X | Y` for type annotations
+   |
+56 | def f(x: Union[str, int : float]) -> None:
+   |          ^^^^^^^^^^^^^^^^^^^^^^^ UP007
+57 |     ...
+   |
+   = help: Convert to `X | Y`
+
+UP007.py:60:10: UP007 Use `X | Y` for type annotations
+   |
+60 | def f(x: Union[x := int]) -> None:
+   |          ^^^^^^^^^^^^^^^ UP007
+61 |     ...
+   |
+   = help: Convert to `X | Y`
 
 UP007.py:64:10: UP007 Use `X | Y` for type annotations
    |
-64 | def f(x: Union[int : float]) -> None:
+64 | def f(x: Union[str, x := int]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^ UP007
+   |          ^^^^^^^^^^^^^^^^^^^^ UP007
 65 |     ...
    |
    = help: Convert to `X | Y`
 
 UP007.py:68:10: UP007 Use `X | Y` for type annotations
    |
-68 | def f(x: Union[str, int : float]) -> None:
+68 | def f(x: Union[lambda: int]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^^^^^^ UP007
+   |          ^^^^^^^^^^^^^^^^^^ UP007
 69 |     ...
    |
    = help: Convert to `X | Y`
 
 UP007.py:72:10: UP007 Use `X | Y` for type annotations
    |
-72 | def f(x: Union[x := int]) -> None:
+72 | def f(x: Union[str, lambda: int]) -> None:
-   |          ^^^^^^^^^^^^^^^ UP007
+   |          ^^^^^^^^^^^^^^^^^^^^^^^ UP007
 73 |     ...
    |
    = help: Convert to `X | Y`
 
-UP007.py:76:10: UP007 Use `X | Y` for type annotations
+UP007.py:83:10: UP007 [*] Use `X | Y` for type annotations
    |
-76 | def f(x: Union[str, x := int]) -> None:
+82 | # Regression test for: https://github.com/astral-sh/ruff/issues/8609
-   |          ^^^^^^^^^^^^^^^^^^^^ UP007
+83 | def f(x: Union[int, str, bytes]) -> None:
-77 |     ...
+   |          ^^^^^^^^^^^^^^^^^^^^^^ UP007
+84 |     ...
    |
    = help: Convert to `X | Y`
 
-UP007.py:80:10: UP007 Use `X | Y` for type annotations
-   |
-80 | def f(x: Union[lambda: int]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^ UP007
-81 |     ...
-   |
-   = help: Convert to `X | Y`
-
-UP007.py:84:10: UP007 Use `X | Y` for type annotations
-   |
-84 | def f(x: Union[str, lambda: int]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^^^^^^ UP007
-85 |     ...
-   |
-   = help: Convert to `X | Y`
-
-UP007.py:88:10: UP007 Use `X | Y` for type annotations
-   |
-88 | def f(x: Optional[int : float]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^^^^ UP007
-89 |     ...
-   |
-   = help: Convert to `X | Y`
-
-UP007.py:92:10: UP007 Use `X | Y` for type annotations
-   |
-92 | def f(x: Optional[str, int : float]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^ UP007
-93 |     ...
-   |
-   = help: Convert to `X | Y`
-
-UP007.py:96:10: UP007 Use `X | Y` for type annotations
-   |
-96 | def f(x: Optional[int, float]) -> None:
-   |          ^^^^^^^^^^^^^^^^^^^^ UP007
-97 |     ...
-   |
-   = help: Convert to `X | Y`
-
-UP007.py:102:28: UP007 [*] Use `X | Y` for type annotations
-    |
-100 |   # Regression test for: https://github.com/astral-sh/ruff/issues/7131
-101 |   class ServiceRefOrValue:
-102 |       service_specification: Optional[
-    |  ____________________________^
-103 | |         list[ServiceSpecificationRef]
-104 | |         | list[ServiceSpecification]
-105 | |     ] = None
-    | |_____^ UP007
-    |
-    = help: Convert to `X | Y`
-
 ℹ Safe fix
-99  99  | 
+80 80 | 
-100 100 | # Regression test for: https://github.com/astral-sh/ruff/issues/7131
+81 81 | 
-101 101 | class ServiceRefOrValue:
+82 82 | # Regression test for: https://github.com/astral-sh/ruff/issues/8609
-102     |-    service_specification: Optional[
+83    |-def f(x: Union[int, str, bytes]) -> None:
-103     |-        list[ServiceSpecificationRef]
+   83 |+def f(x: int | str | bytes) -> None:
-104     |-        | list[ServiceSpecification]
+84 84 |     ...
-105     |-    ] = None
-    102 |+    service_specification: list[ServiceSpecificationRef] | list[ServiceSpecification] | None = None
-106 103 | 
-107 104 | 
-108 105 | # Regression test for: https://github.com/astral-sh/ruff/issues/7201
-
-UP007.py:110:28: UP007 [*] Use `X | Y` for type annotations
-    |
-108 | # Regression test for: https://github.com/astral-sh/ruff/issues/7201
-109 | class ServiceRefOrValue:
-110 |     service_specification: Optional[str]is not True = None
-    |                            ^^^^^^^^^^^^^ UP007
-    |
-    = help: Convert to `X | Y`
-
-ℹ Safe fix
-107 107 | 
-108 108 | # Regression test for: https://github.com/astral-sh/ruff/issues/7201
-109 109 | class ServiceRefOrValue:
-110     |-    service_specification: Optional[str]is not True = None
-    110 |+    service_specification: str | None is not True = None
-111 111 | 
-112 112 | 
-113 113 | # Regression test for: https://github.com/astral-sh/ruff/issues/7452
-
-UP007.py:120:10: UP007 [*] Use `X | Y` for type annotations
-    |
-119 | # Regression test for: https://github.com/astral-sh/ruff/issues/8609
-120 | def f(x: Union[int, str, bytes]) -> None:
-    |          ^^^^^^^^^^^^^^^^^^^^^^ UP007
-121 |     ...
-    |
-    = help: Convert to `X | Y`
-
-ℹ Safe fix
-117 117 | 
-118 118 | 
-119 119 | # Regression test for: https://github.com/astral-sh/ruff/issues/8609
-120     |-def f(x: Union[int, str, bytes]) -> None:
-    120 |+def f(x: int | str | bytes) -> None:
-121 121 |     ...

crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP045.py.snap

@@ -0,0 +1,151 @@
+---
+source: crates/ruff_linter/src/rules/pyupgrade/mod.rs
+snapshot_kind: text
+---
+UP045.py:5:10: UP007 [*] Use `X | Y` for type annotations
+  |
+5 | def f(x: Optional[str]) -> None:
+  |          ^^^^^^^^^^^^^ UP007
+6 |     ...
+  |
+  = help: Convert to `X | Y`
+
+ℹ Safe fix
+2 2 | from typing import Optional
+3 3 | 
+4 4 | 
+5   |-def f(x: Optional[str]) -> None:
+  5 |+def f(x: str | None) -> None:
+6 6 |     ...
+7 7 | 
+8 8 | 
+
+UP045.py:9:10: UP007 [*] Use `X | Y` for type annotations
+   |
+ 9 | def f(x: typing.Optional[str]) -> None:
+   |          ^^^^^^^^^^^^^^^^^^^^ UP007
+10 |     ...
+   |
+   = help: Convert to `X | Y`
+
+ℹ Safe fix
+6  6  |     ...
+7  7  | 
+8  8  | 
+9     |-def f(x: typing.Optional[str]) -> None:
+   9  |+def f(x: str | None) -> None:
+10 10 |     ...
+11 11 | 
+12 12 | 
+
+UP045.py:14:8: UP007 [*] Use `X | Y` for type annotations
+   |
+13 | def f() -> None:
+14 |     x: Optional[str]
+   |        ^^^^^^^^^^^^^ UP007
+15 |     x = Optional[str]
+   |
+   = help: Convert to `X | Y`
+
+ℹ Safe fix
+11 11 | 
+12 12 | 
+13 13 | def f() -> None:
+14    |-    x: Optional[str]
+   14 |+    x: str | None
+15 15 |     x = Optional[str]
+16 16 | 
+17 17 | 
+
+UP045.py:15:9: UP007 Use `X | Y` for type annotations
+   |
+13 | def f() -> None:
+14 |     x: Optional[str]
+15 |     x = Optional[str]
+   |         ^^^^^^^^^^^^^ UP007
+   |
+   = help: Convert to `X | Y`
+
+UP045.py:18:15: UP007 [*] Use `X | Y` for type annotations
+   |
+18 | def f(x: list[Optional[int]]) -> None:
+   |               ^^^^^^^^^^^^^ UP007
+19 |     ...
+   |
+   = help: Convert to `X | Y`
+
+ℹ Safe fix
+15 15 |     x = Optional[str]
+16 16 | 
+17 17 | 
+18    |-def f(x: list[Optional[int]]) -> None:
+   18 |+def f(x: list[int | None]) -> None:
+19 19 |     ...
+20 20 | 
+21 21 | 
+
+UP045.py:22:10: UP007 Use `X | Y` for type annotations
+   |
+22 | def f(x: Optional[int : float]) -> None:
+   |          ^^^^^^^^^^^^^^^^^^^^^ UP007
+23 |     ...
+   |
+   = help: Convert to `X | Y`
+
+UP045.py:26:10: UP007 Use `X | Y` for type annotations
+   |
+26 | def f(x: Optional[str, int : float]) -> None:
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^ UP007
+27 |     ...
+   |
+   = help: Convert to `X | Y`
+
+UP045.py:30:10: UP007 Use `X | Y` for type annotations
+   |
+30 | def f(x: Optional[int, float]) -> None:
+   |          ^^^^^^^^^^^^^^^^^^^^ UP007
+31 |     ...
+   |
+   = help: Convert to `X | Y`
+
+UP045.py:36:28: UP007 [*] Use `X | Y` for type annotations
+   |
+34 |   # Regression test for: https://github.com/astral-sh/ruff/issues/7131
+35 |   class ServiceRefOrValue:
+36 |       service_specification: Optional[
+   |  ____________________________^
+37 | |         list[ServiceSpecificationRef]
+38 | |         | list[ServiceSpecification]
+39 | |     ] = None
+   | |_____^ UP007
+   |
+   = help: Convert to `X | Y`
+
+ℹ Safe fix
+33 33 | 
+34 34 | # Regression test for: https://github.com/astral-sh/ruff/issues/7131
+35 35 | class ServiceRefOrValue:
+36    |-    service_specification: Optional[
+37    |-        list[ServiceSpecificationRef]
+38    |-        | list[ServiceSpecification]
+39    |-    ] = None
+   36 |+    service_specification: list[ServiceSpecificationRef] | list[ServiceSpecification] | None = None
+40 37 | 
+41 38 | 
+42 39 | # Regression test for: https://github.com/astral-sh/ruff/issues/7201
+
+UP045.py:44:28: UP007 [*] Use `X | Y` for type annotations
+   |
+42 | # Regression test for: https://github.com/astral-sh/ruff/issues/7201
+43 | class ServiceRefOrValue:
+44 |     service_specification: Optional[str]is not True = None
+   |                            ^^^^^^^^^^^^^ UP007
+   |
+   = help: Convert to `X | Y`
+
+ℹ Safe fix
+41 41 | 
+42 42 | # Regression test for: https://github.com/astral-sh/ruff/issues/7201
+43 43 | class ServiceRefOrValue:
+44    |-    service_specification: Optional[str]is not True = None
+   44 |+    service_specification: str | None is not True = None

crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__up007_preview.snap

@@ -0,0 +1,5 @@
+---
+source: crates/ruff_linter/src/rules/pyupgrade/mod.rs
+snapshot_kind: text
+---
+

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

@@ -374,7 +374,7 @@ mod tests {
     fn redirects() -> Result<()> {
         let diagnostics = test_path(
             Path::new("ruff/redirects.py"),
-            &settings::LinterSettings::for_rules(vec![Rule::NonPEP604Annotation]),
+            &settings::LinterSettings::for_rule(Rule::NonPEP604AnnotationUnion),
         )?;
         assert_messages!(diagnostics);
         Ok(())

ruff.schema.json

@@ -4134,6 +4134,7 @@
         "UP042",
         "UP043",
         "UP044",
+        "UP045",
         "W",
         "W1",
         "W19",