[`pycodestyle`] Remove deprecated functionality from `type-comparison` (`E721`) (#11220)

## Summary

Stabilizes `E721` behavior implemented in #7905.

The functionality change in `E721` was implemented in #7905, released in
[v0.1.2](https://github.com/astral-sh/ruff/releases/tag/v0.1.2). And
seems functionally stable since #9676, without an explicit release but
would correspond to
[v0.2.0](https://github.com/astral-sh/ruff/releases/tag/v0.2.0). So the
deprecated functionally should be removable in the next minor release.

resolves: #6465

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

@@ -69,7 +69,6 @@ mod tests {
     }
 
     #[test_case(Rule::IsLiteral, Path::new("constant_literals.py"))]
-    #[test_case(Rule::TypeComparison, Path::new("E721.py"))]
     #[test_case(Rule::ModuleImportNotAtTopOfFile, Path::new("E402_2.py"))]
     #[test_case(Rule::RedundantBackslash, Path::new("E502.py"))]
     #[test_case(Rule::TooManyNewlinesAtEndOfFile, Path::new("W391_0.py"))]

crates/ruff_linter/src/rules/pycodestyle/rules/type_comparison.rs

@@ -7,7 +7,6 @@ use ruff_python_semantic::SemanticModel;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
-use crate::settings::types::PreviewMode;
 
 /// ## What it does
 /// Checks for object type comparisons using `==` and other comparison
@@ -37,119 +36,19 @@ use crate::settings::types::PreviewMode;
 ///     pass
 /// ```
 #[violation]
-pub struct TypeComparison {
+pub struct TypeComparison;
-    preview: PreviewMode,
-}
 
 impl Violation for TypeComparison {
     #[derive_message_formats]
     fn message(&self) -> String {
-        match self.preview {
+        format!(
-            PreviewMode::Disabled => format!("Do not compare types, use `isinstance()`"),
-            PreviewMode::Enabled => format!(
             "Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks"
-            ),
+        )
-        }
     }
 }
 
 /// E721
 pub(crate) fn type_comparison(checker: &mut Checker, compare: &ast::ExprCompare) {
-    match checker.settings.preview {
-        PreviewMode::Disabled => deprecated_type_comparison(checker, compare),
-        PreviewMode::Enabled => preview_type_comparison(checker, compare),
-    }
-}
-
-fn deprecated_type_comparison(checker: &mut Checker, compare: &ast::ExprCompare) {
-    for ((left, right), op) in std::iter::once(compare.left.as_ref())
-        .chain(compare.comparators.iter())
-        .tuple_windows()
-        .zip(compare.ops.iter())
-    {
-        if !matches!(op, CmpOp::Is | CmpOp::IsNot | CmpOp::Eq | CmpOp::NotEq) {
-            continue;
-        }
-
-        // Left-hand side must be, e.g., `type(obj)`.
-        let Expr::Call(ast::ExprCall { func, .. }) = left else {
-            continue;
-        };
-
-        let semantic = checker.semantic();
-
-        if !semantic.match_builtin_expr(func, "type") {
-            continue;
-        }
-
-        // Right-hand side must be, e.g., `type(1)` or `int`.
-        match right {
-            Expr::Call(ast::ExprCall {
-                func, arguments, ..
-            }) => {
-                // Ex) `type(obj) is type(1)`
-                if semantic.match_builtin_expr(func, "type") {
-                    // Allow comparison for types which are not obvious.
-                    if arguments
-                        .args
-                        .first()
-                        .is_some_and(|arg| !arg.is_name_expr() && !arg.is_none_literal_expr())
-                    {
-                        checker.diagnostics.push(Diagnostic::new(
-                            TypeComparison {
-                                preview: PreviewMode::Disabled,
-                            },
-                            compare.range(),
-                        ));
-                    }
-                }
-            }
-            Expr::Attribute(ast::ExprAttribute { value, .. }) => {
-                // Ex) `type(obj) is types.NoneType`
-                if semantic
-                    .resolve_qualified_name(value.as_ref())
-                    .is_some_and(|qualified_name| {
-                        matches!(qualified_name.segments(), ["types", ..])
-                    })
-                {
-                    checker.diagnostics.push(Diagnostic::new(
-                        TypeComparison {
-                            preview: PreviewMode::Disabled,
-                        },
-                        compare.range(),
-                    ));
-                }
-            }
-            Expr::Name(ast::ExprName { id, .. }) => {
-                // Ex) `type(obj) is int`
-                if matches!(
-                    id.as_str(),
-                    "int"
-                        | "str"
-                        | "float"
-                        | "bool"
-                        | "complex"
-                        | "bytes"
-                        | "list"
-                        | "dict"
-                        | "set"
-                        | "memoryview"
-                ) && semantic.has_builtin_binding(id)
-                {
-                    checker.diagnostics.push(Diagnostic::new(
-                        TypeComparison {
-                            preview: PreviewMode::Disabled,
-                        },
-                        compare.range(),
-                    ));
-                }
-            }
-            _ => {}
-        }
-    }
-}
-
-pub(crate) fn preview_type_comparison(checker: &mut Checker, compare: &ast::ExprCompare) {
     for (left, right) in std::iter::once(compare.left.as_ref())
         .chain(compare.comparators.iter())
         .tuple_windows()
@@ -165,12 +64,9 @@ pub(crate) fn preview_type_comparison(checker: &mut Checker, compare: &ast::Expr
             }
 
             // Disallow the comparison.
-            checker.diagnostics.push(Diagnostic::new(
+            checker
-                TypeComparison {
+                .diagnostics
-                    preview: PreviewMode::Enabled,
+                .push(Diagnostic::new(TypeComparison, compare.range()));
-                },
-                compare.range(),
-            ));
         }
     }
 }

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E721_E721.py.snap

@@ -1,7 +1,7 @@
 ---
 source: crates/ruff_linter/src/rules/pycodestyle/mod.rs
 ---
-E721.py:2:4: E721 Do not compare types, use `isinstance()`
+E721.py:2:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
   |
 1 | #: E721
 2 | if type(res) == type(42):
@@ -10,7 +10,7 @@ E721.py:2:4: E721 Do not compare types, use `isinstance()`
 4 | #: E721
   |
 
-E721.py:5:4: E721 Do not compare types, use `isinstance()`
+E721.py:5:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
   |
 3 |     pass
 4 | #: E721
@@ -20,7 +20,7 @@ E721.py:5:4: E721 Do not compare types, use `isinstance()`
 7 | #: E721
   |
 
-E721.py:8:4: E721 Do not compare types, use `isinstance()`
+E721.py:8:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
  6 |     pass
  7 | #: E721
@@ -30,17 +30,7 @@ E721.py:8:4: E721 Do not compare types, use `isinstance()`
 10 | #: Okay
    |
 
-E721.py:18:4: E721 Do not compare types, use `isinstance()`
+E721.py:21:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-16 | import types
-17 | 
-18 | if type(res) is not types.ListType:
-   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-19 |     pass
-20 | #: E721
-   |
-
-E721.py:21:8: E721 Do not compare types, use `isinstance()`
    |
 19 |     pass
 20 | #: E721
@@ -50,7 +40,7 @@ E721.py:21:8: E721 Do not compare types, use `isinstance()`
 23 | assert type(res) == type([])
    |
 
-E721.py:23:8: E721 Do not compare types, use `isinstance()`
+E721.py:23:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
 21 | assert type(res) == type(False) or type(res) == type(None)
 22 | #: E721
@@ -60,7 +50,7 @@ E721.py:23:8: E721 Do not compare types, use `isinstance()`
 25 | assert type(res) == type(())
    |
 
-E721.py:25:8: E721 Do not compare types, use `isinstance()`
+E721.py:25:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
 23 | assert type(res) == type([])
 24 | #: E721
@@ -70,7 +60,7 @@ E721.py:25:8: E721 Do not compare types, use `isinstance()`
 27 | assert type(res) == type((0,))
    |
 
-E721.py:27:8: E721 Do not compare types, use `isinstance()`
+E721.py:27:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
 25 | assert type(res) == type(())
 26 | #: E721
@@ -80,7 +70,7 @@ E721.py:27:8: E721 Do not compare types, use `isinstance()`
 29 | assert type(res) == type((0))
    |
 
-E721.py:29:8: E721 Do not compare types, use `isinstance()`
+E721.py:29:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
 27 | assert type(res) == type((0,))
 28 | #: E721
@@ -90,7 +80,7 @@ E721.py:29:8: E721 Do not compare types, use `isinstance()`
 31 | assert type(res) != type((1, ))
    |
 
-E721.py:31:8: E721 Do not compare types, use `isinstance()`
+E721.py:31:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
 29 | assert type(res) == type((0))
 30 | #: E721
@@ -100,27 +90,7 @@ E721.py:31:8: E721 Do not compare types, use `isinstance()`
 33 | assert type(res) is type((1, ))
    |
 
-E721.py:33:8: E721 Do not compare types, use `isinstance()`
+E721.py:37:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-31 | assert type(res) != type((1, ))
-32 | #: Okay
-33 | assert type(res) is type((1, ))
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-34 | #: Okay
-35 | assert type(res) is not type((1, ))
-   |
-
-E721.py:35:8: E721 Do not compare types, use `isinstance()`
-   |
-33 | assert type(res) is type((1, ))
-34 | #: Okay
-35 | assert type(res) is not type((1, ))
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-36 | #: E211 E721
-37 | assert type(res) == type ([2, ])
-   |
-
-E721.py:37:8: E721 Do not compare types, use `isinstance()`
    |
 35 | assert type(res) is not type((1, ))
 36 | #: E211 E721
@@ -130,7 +100,7 @@ E721.py:37:8: E721 Do not compare types, use `isinstance()`
 39 | assert type(res) == type( ( ) )
    |
 
-E721.py:39:8: E721 Do not compare types, use `isinstance()`
+E721.py:39:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
 37 | assert type(res) == type ([2, ])
 38 | #: E201 E201 E202 E721
@@ -140,7 +110,7 @@ E721.py:39:8: E721 Do not compare types, use `isinstance()`
 41 | assert type(res) == type( (0, ) )
    |
 
-E721.py:41:8: E721 Do not compare types, use `isinstance()`
+E721.py:41:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
 39 | assert type(res) == type( ( ) )
 40 | #: E201 E202 E721
@@ -149,25 +119,26 @@ E721.py:41:8: E721 Do not compare types, use `isinstance()`
 42 | #:
    |
 
-E721.py:107:12: E721 Do not compare types, use `isinstance()`
+E721.py:59:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
    |
-105 |     def asdf(self, value: str | None):
+57 |     pass
-106 |         #: E721
+58 | #: E721
-107 |         if type(value) is str:
+59 | if type(res) == type:
-    |            ^^^^^^^^^^^^^^^^^^ E721
+   |    ^^^^^^^^^^^^^^^^^ E721
-108 |             ...
+60 |     pass
+61 | #: Okay
    |
 
-E721.py:117:12: E721 Do not compare types, use `isinstance()`
+E721.py:140:1: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
     |
-115 |     def asdf(self, value: str | None):
+139 | #: E721
-116 |         #: E721
+140 | dtype == float
-117 |         if type(value) is str:
+    | ^^^^^^^^^^^^^^ E721
-    |            ^^^^^^^^^^^^^^^^^^ E721
+141 | 
-118 |             ...
+142 | import builtins
     |
 
-E721.py:144:4: E721 Do not compare types, use `isinstance()`
+E721.py:144:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
     |
 142 | import builtins
 143 | 

crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__preview__E721_E721.py.snap

@@ -1,148 +0,0 @@
----
-source: crates/ruff_linter/src/rules/pycodestyle/mod.rs
----
-E721.py:2:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-  |
-1 | #: E721
-2 | if type(res) == type(42):
-  |    ^^^^^^^^^^^^^^^^^^^^^ E721
-3 |     pass
-4 | #: E721
-  |
-
-E721.py:5:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-  |
-3 |     pass
-4 | #: E721
-5 | if type(res) != type(""):
-  |    ^^^^^^^^^^^^^^^^^^^^^ E721
-6 |     pass
-7 | #: E721
-  |
-
-E721.py:8:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
- 6 |     pass
- 7 | #: E721
- 8 | if type(res) == memoryview:
-   |    ^^^^^^^^^^^^^^^^^^^^^^^ E721
- 9 |     pass
-10 | #: Okay
-   |
-
-E721.py:21:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-19 |     pass
-20 | #: E721
-21 | assert type(res) == type(False) or type(res) == type(None)
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-22 | #: E721
-23 | assert type(res) == type([])
-   |
-
-E721.py:23:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-21 | assert type(res) == type(False) or type(res) == type(None)
-22 | #: E721
-23 | assert type(res) == type([])
-   |        ^^^^^^^^^^^^^^^^^^^^^ E721
-24 | #: E721
-25 | assert type(res) == type(())
-   |
-
-E721.py:25:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-23 | assert type(res) == type([])
-24 | #: E721
-25 | assert type(res) == type(())
-   |        ^^^^^^^^^^^^^^^^^^^^^ E721
-26 | #: E721
-27 | assert type(res) == type((0,))
-   |
-
-E721.py:27:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-25 | assert type(res) == type(())
-26 | #: E721
-27 | assert type(res) == type((0,))
-   |        ^^^^^^^^^^^^^^^^^^^^^^^ E721
-28 | #: E721
-29 | assert type(res) == type((0))
-   |
-
-E721.py:29:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-27 | assert type(res) == type((0,))
-28 | #: E721
-29 | assert type(res) == type((0))
-   |        ^^^^^^^^^^^^^^^^^^^^^^ E721
-30 | #: E721
-31 | assert type(res) != type((1, ))
-   |
-
-E721.py:31:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-29 | assert type(res) == type((0))
-30 | #: E721
-31 | assert type(res) != type((1, ))
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-32 | #: Okay
-33 | assert type(res) is type((1, ))
-   |
-
-E721.py:37:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-35 | assert type(res) is not type((1, ))
-36 | #: E211 E721
-37 | assert type(res) == type ([2, ])
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-38 | #: E201 E201 E202 E721
-39 | assert type(res) == type( ( ) )
-   |
-
-E721.py:39:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-37 | assert type(res) == type ([2, ])
-38 | #: E201 E201 E202 E721
-39 | assert type(res) == type( ( ) )
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^ E721
-40 | #: E201 E202 E721
-41 | assert type(res) == type( (0, ) )
-   |
-
-E721.py:41:8: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-39 | assert type(res) == type( ( ) )
-40 | #: E201 E202 E721
-41 | assert type(res) == type( (0, ) )
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-42 | #:
-   |
-
-E721.py:59:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-   |
-57 |     pass
-58 | #: E721
-59 | if type(res) == type:
-   |    ^^^^^^^^^^^^^^^^^ E721
-60 |     pass
-61 | #: Okay
-   |
-
-E721.py:140:1: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-    |
-139 | #: E721
-140 | dtype == float
-    | ^^^^^^^^^^^^^^ E721
-141 | 
-142 | import builtins
-    |
-
-E721.py:144:4: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks
-    |
-142 | import builtins
-143 | 
-144 | if builtins.type(res) == memoryview:  # E721
-    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E721
-145 |     pass
-    |