Feedback, add conformance test

conformance/results/mypy/classes_classvar.toml

@@ -4,7 +4,6 @@ Internal error if TypeVarTuple is used in ClassVar.
 Does not reject use of ParamSpec in ClassVar.
 Rejects ClassVar nested in Annotated.
 Does not reject use of ClassVar in TypeAlias definition.
-Does not infer type of ClassVar from assignment if no type is provided.
 """
 output = """
 classes_classvar.py:38: error: ClassVar[...] must have at most one type argument  [valid-type]
@@ -15,24 +14,22 @@ classes_classvar.py:46: error: ClassVar cannot contain type variables  [misc]
 classes_classvar.py:52: error: Incompatible types in assignment (expression has type "dict[Never, Never]", variable has type "list[str]")  [assignment]
 classes_classvar.py:54: error: Variable should not be annotated with both ClassVar and Final  [misc]
 classes_classvar.py:55: error: Invalid type: ClassVar nested inside other type  [valid-type]
-classes_classvar.py:61: error: Invalid type: ClassVar nested inside other type  [valid-type]
-classes_classvar.py:63: error: ClassVar can only be used for assignments in class body  [misc]
-classes_classvar.py:64: error: ClassVar can only be used for assignments in class body  [misc]
-classes_classvar.py:65: error: ClassVar can only be used for assignments in class body  [misc]
-classes_classvar.py:67: error: ClassVar can only be used for assignments in class body  [misc]
+classes_classvar.py:67: error: Invalid type: ClassVar nested inside other type  [valid-type]
+classes_classvar.py:69: error: ClassVar can only be used for assignments in class body  [misc]
+classes_classvar.py:70: error: ClassVar can only be used for assignments in class body  [misc]
 classes_classvar.py:71: error: ClassVar can only be used for assignments in class body  [misc]
-classes_classvar.py:78: error: Expression is of type "Any", not "float"  [assert-type]
-classes_classvar.py:105: error: Cannot assign to class variable "stats" via instance  [misc]
-classes_classvar.py:134: error: Incompatible types in assignment (expression has type "ProtoAImpl", variable has type "ProtoA")  [assignment]
-classes_classvar.py:134: note: "ProtoAImpl" is missing following "ProtoA" protocol member:
-classes_classvar.py:134: note:     z
-classes_classvar.py:134: note: Protocol member ProtoA.x expected class variable, got instance variable
-classes_classvar.py:134: note: Protocol member ProtoA.y expected class variable, got instance variable
+classes_classvar.py:73: error: ClassVar can only be used for assignments in class body  [misc]
+classes_classvar.py:77: error: ClassVar can only be used for assignments in class body  [misc]
+classes_classvar.py:111: error: Cannot assign to class variable "stats" via instance  [misc]
+classes_classvar.py:140: error: Incompatible types in assignment (expression has type "ProtoAImpl", variable has type "ProtoA")  [assignment]
+classes_classvar.py:140: note: "ProtoAImpl" is missing following "ProtoA" protocol member:
+classes_classvar.py:140: note:     z
+classes_classvar.py:140: note: Protocol member ProtoA.x expected class variable, got instance variable
+classes_classvar.py:140: note: Protocol member ProtoA.y expected class variable, got instance variable
 """
 conformance_automated = "Fail"
 errors_diff = """
 Line 47: Expected 1 errors
-Line 72: Expected 1 errors
-Line 61: Unexpected errors ['classes_classvar.py:61: error: Invalid type: ClassVar nested inside other type  [valid-type]']
-Line 78: Unexpected errors ['classes_classvar.py:78: error: Expression is of type "Any", not "float"  [assert-type]']
+Line 78: Expected 1 errors
+Line 67: Unexpected errors ['classes_classvar.py:67: error: Invalid type: ClassVar nested inside other type  [valid-type]']
 """

conformance/results/mypy/version.toml

@@ -1,2 +1,2 @@
 version = "mypy 1.15.0"
-test_duration = 1.8
+test_duration = 2.1

conformance/results/pyre/classes_classvar.toml

@@ -3,6 +3,7 @@ notes = """
 Does not reject use of TypeVar in ClassVar.
 Does not reject use of ParamSpec in ClassVar.
 Does not reject use of ClassVar as a generic type argument.
+Does not allow ClassVar to be used without an assigned value.
 Does not reject use of ClassVar in parameter type annotation.
 Does not reject use of ClassVar in local variable annotation.
 Does not reject use of ClassVar in instance variable annotation.
@@ -15,11 +16,11 @@ classes_classvar.py:38:10 Invalid type parameters [24]: Generic type `CV` expect
 classes_classvar.py:39:10 Invalid type [31]: Expression `typing.ClassVar[3]` is not a valid type.
 classes_classvar.py:40:13 Unbound name [10]: Name `var` is used but not defined in the current scope.
 classes_classvar.py:52:4 Incompatible attribute type [8]: Attribute `bad8` declared in class `ClassA` has type `List[str]` but is used as type `Dict[Variable[_KT], Variable[_VT]]`.
-classes_classvar.py:65:8 Undefined attribute [16]: `ClassA` has no attribute `xx`.
-classes_classvar.py:68:8 Incompatible return type [7]: Expected `CV[int]` but got `int`.
-classes_classvar.py:78:0 Assert type [70]: Expected `float` but got `typing.Any`.
-classes_classvar.py:105:0 Invalid assignment [41]: Assigning to class variable through instance, did you mean to assign to `Starship.stats` instead?
-classes_classvar.py:134:0 Incompatible variable type [9]: a is declared to have type `ProtoA` but is used as type `ProtoAImpl`.
+classes_classvar.py:66:4 Uninitialized attribute [13]: Attribute `good5` is declared in class `ClassA` to have type `typing.Any` but is never initialized.
+classes_classvar.py:71:8 Undefined attribute [16]: `ClassA` has no attribute `xx`.
+classes_classvar.py:74:8 Incompatible return type [7]: Expected `CV[int]` but got `int`.
+classes_classvar.py:111:0 Invalid assignment [41]: Assigning to class variable through instance, did you mean to assign to `Starship.stats` instead?
+classes_classvar.py:140:0 Incompatible variable type [9]: a is declared to have type `ProtoA` but is used as type `ProtoAImpl`.
 """
 conformance_automated = "Fail"
 errors_diff = """
@@ -28,11 +29,11 @@ Line 46: Expected 1 errors
 Line 47: Expected 1 errors
 Line 54: Expected 1 errors
 Line 55: Expected 1 errors
-Line 63: Expected 1 errors
-Line 64: Expected 1 errors
-Line 67: Expected 1 errors
-Line 71: Expected 1 errors
-Line 72: Expected 1 errors
-Line 68: Unexpected errors ['classes_classvar.py:68:8 Incompatible return type [7]: Expected `CV[int]` but got `int`.']
-Line 78: Unexpected errors ['classes_classvar.py:78:0 Assert type [70]: Expected `float` but got `typing.Any`.']
+Line 69: Expected 1 errors
+Line 70: Expected 1 errors
+Line 73: Expected 1 errors
+Line 77: Expected 1 errors
+Line 78: Expected 1 errors
+Line 66: Unexpected errors ['classes_classvar.py:66:4 Uninitialized attribute [13]: Attribute `good5` is declared in class `ClassA` to have type `typing.Any` but is never initialized.']
+Line 74: Unexpected errors ['classes_classvar.py:74:8 Incompatible return type [7]: Expected `CV[int]` but got `int`.']
 """

conformance/results/pyre/version.toml

@@ -1,2 +1,2 @@
 version = "pyre 0.9.23"
-test_duration = 6.5
+test_duration = 3.9

conformance/results/pyright/classes_classvar.toml

@@ -9,15 +9,15 @@ classes_classvar.py:47:20 - error: "ClassVar" type cannot include type variables
 classes_classvar.py:52:33 - error: Type "dict[Any, Any]" is not assignable to declared type "list[str]" (reportAssignmentType)
 classes_classvar.py:54:17 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
 classes_classvar.py:55:17 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
-classes_classvar.py:63:26 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
-classes_classvar.py:64:12 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
-classes_classvar.py:65:18 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
-classes_classvar.py:67:26 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
-classes_classvar.py:71:8 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
-classes_classvar.py:72:20 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
-classes_classvar.py:105:14 - error: Cannot assign to attribute "stats" for class "Starship"
+classes_classvar.py:69:26 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
+classes_classvar.py:70:12 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
+classes_classvar.py:71:18 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
+classes_classvar.py:73:26 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
+classes_classvar.py:77:8 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
+classes_classvar.py:78:20 - error: "ClassVar" is not allowed in this context (reportInvalidTypeForm)
+classes_classvar.py:111:14 - error: Cannot assign to attribute "stats" for class "Starship"
   Attribute "stats" cannot be assigned through a class instance because it is a ClassVar (reportAttributeAccessIssue)
-classes_classvar.py:134:13 - error: Type "ProtoAImpl" is not assignable to declared type "ProtoA"
+classes_classvar.py:140:13 - error: Type "ProtoAImpl" is not assignable to declared type "ProtoA"
   "ProtoAImpl" is incompatible with protocol "ProtoA"
     "x" is defined as a ClassVar in protocol
     "y" is defined as a ClassVar in protocol (reportAssignmentType)

conformance/results/pyright/version.toml

@@ -1,2 +1,2 @@
 version = "pyright 1.1.394"
-test_duration = 1.3
+test_duration = 2.3

conformance/results/pytype/classes_classvar.toml

@@ -4,6 +4,7 @@ Does not reject use of TypeVar in ClassVar.
 Does not reject use of ParamSpec in ClassVar.
 Does not reject use of ClassVar as a generic type argument.
 Rejects initialization of ClassVar if no type argument is provided.
+Does not infer ClassVar with no type argument and no assigned value as Any.
 Does not reject use of ClassVar in parameter type annotation.
 Does not reject use of ClassVar in local variable annotation.
 Does not reject use of ClassVar in instance variable annotation.
@@ -85,27 +86,27 @@ classes_classvar.py:52:5: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in ClassA
     bad8: ClassVar[list[str]] = {}  # E: type violation in initialization
     \u001b[1m\u001b[31m~~~~\u001b[39m\u001b[0m
 
-classes_classvar.py:60:5: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in ClassA: Type annotation for good4 does not match type of assignment [annotation-type-mismatch]
+classes_classvar.py:63:5: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in ClassA: Type annotation for good4 does not match type of assignment [annotation-type-mismatch]
 
     good4: ClassVar = 3.1
     \u001b[1m\u001b[31m~~~~~\u001b[39m\u001b[0m
 
-classes_classvar.py:68:16: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in method2: bad return type [bad-return-type]
+classes_classvar.py:74:16: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in method2: bad return type [bad-return-type]
 
         return 3
                \u001b[1m\u001b[31m~\u001b[39m\u001b[0m
 
-classes_classvar.py:78:1: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in <module>: ClassVar [assert-type]
+classes_classvar.py:84:1: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in <module>: ClassVar [assert-type]
 
-assert_type(ClassA.good4, float)
-\u001b[1m\u001b[31m~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\u001b[39m\u001b[0m
+assert_type(ClassA.good5, Any)
+\u001b[1m\u001b[31m~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\u001b[39m\u001b[0m
 
-classes_classvar.py:124:5: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in ProtoA: Type annotation for z does not match type of assignment [annotation-type-mismatch]
+classes_classvar.py:130:5: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in ProtoA: Type annotation for z does not match type of assignment [annotation-type-mismatch]
 
     z: CV = [""]
     \u001b[1m\u001b[31m~\u001b[39m\u001b[0m
 
-classes_classvar.py:134:1: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in <module>: Type annotation for a does not match type of assignment [annotation-type-mismatch]
+classes_classvar.py:140:1: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in <module>: Type annotation for a does not match type of assignment [annotation-type-mismatch]
 
 a: ProtoA = ProtoAImpl()  # E: y is not a ClassVar
 \u001b[1m\u001b[31m~\u001b[39m\u001b[0m
@@ -118,17 +119,17 @@ Line 46: Expected 1 errors
 Line 47: Expected 1 errors
 Line 54: Expected 1 errors
 Line 55: Expected 1 errors
-Line 63: Expected 1 errors
-Line 64: Expected 1 errors
-Line 65: Expected 1 errors
-Line 67: Expected 1 errors
+Line 69: Expected 1 errors
+Line 70: Expected 1 errors
 Line 71: Expected 1 errors
-Line 72: Expected 1 errors
-Line 105: Expected 1 errors
+Line 73: Expected 1 errors
+Line 77: Expected 1 errors
+Line 78: Expected 1 errors
+Line 111: Expected 1 errors
 Line 7: Unexpected errors ['classes_classvar.py:7:1: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in <module>: typing.TypeVarTuple not supported yet [not-supported-yet]']
 Line 29: Unexpected errors ['classes_classvar.py:29:6: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in <module>: Function TypeVarTuple.__init__ expects 1 arg(s), got 2 [wrong-arg-count]']
-Line 60: Unexpected errors ['classes_classvar.py:60:5: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in ClassA: Type annotation for good4 does not match type of assignment [annotation-type-mismatch]']
-Line 68: Unexpected errors ['classes_classvar.py:68:16: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in method2: bad return type [bad-return-type]']
-Line 78: Unexpected errors ['classes_classvar.py:78:1: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in <module>: ClassVar [assert-type]']
-Line 124: Unexpected errors ['classes_classvar.py:124:5: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in ProtoA: Type annotation for z does not match type of assignment [annotation-type-mismatch]']
+Line 63: Unexpected errors ['classes_classvar.py:63:5: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in ClassA: Type annotation for good4 does not match type of assignment [annotation-type-mismatch]']
+Line 74: Unexpected errors ['classes_classvar.py:74:16: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in method2: bad return type [bad-return-type]']
+Line 84: Unexpected errors ['classes_classvar.py:84:1: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in <module>: ClassVar [assert-type]']
+Line 130: Unexpected errors ['classes_classvar.py:130:5: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in ProtoA: Type annotation for z does not match type of assignment [annotation-type-mismatch]']
 """

conformance/results/pytype/version.toml

@@ -1,2 +1,2 @@
 version = "pytype 2024.10.11"
-test_duration = 34.9
+test_duration = 43.3

conformance/results/results.html

@@ -159,16 +159,16 @@ <h3>Python Type System Conformance Test Results</h3>
         <div class="table_container"><table><tbody>
 <tr><th class="col1">&nbsp;</th>
 <th class='tc-header'><div class='tc-name'>mypy 1.15.0</div>
-<div class='tc-time'>1.8sec</div>
+<div class='tc-time'>2.1sec</div>
 </th>
 <th class='tc-header'><div class='tc-name'>pyright 1.1.394</div>
-<div class='tc-time'>1.3sec</div>
+<div class='tc-time'>2.3sec</div>
 </th>
 <th class='tc-header'><div class='tc-name'>pyre 0.9.23</div>
-<div class='tc-time'>6.5sec</div>
+<div class='tc-time'>3.9sec</div>
 </th>
 <th class='tc-header'><div class='tc-name'>pytype 2024.10.11</div>
-<div class='tc-time'>34.9sec</div>
+<div class='tc-time'>43.3sec</div>
 </th>
 </tr>
 <tr><th class="column" colspan="5">

conformance/tests/classes_classvar.py

@@ -57,8 +57,14 @@ class ClassA(Generic[T, P]):
     good1: CV[int] = 1
     good2: ClassVar[list[str]] = []
     good3: ClassVar[Any] = 1
+    # > If an assigned value is available, the type should be inferred as some type
+    # > to which this value is assignable.
+    # Here, type checkers could infer good4 as `float` or `Any`, for example.
     good4: ClassVar = 3.1
-    good5: Annotated[ClassVar[list[int]], ""] = []
+    # > If the `ClassVar` qualifier is used without any assigned value, the type
+    # > should be inferred as `Any`:
+    good5: ClassVar
+    good6: Annotated[ClassVar[list[int]], ""] = []
 
     def method1(self, a: ClassVar[int]):  # E: ClassVar not allowed here
         x: ClassVar[str] = ""  # E: ClassVar not allowed here
@@ -75,7 +81,7 @@ def method2(self) -> ClassVar[int]:  # E: ClassVar not allowed here
 assert_type(ClassA.good1, int)
 assert_type(ClassA.good2, list[str])
 assert_type(ClassA.good3, Any)
-assert_type(ClassA.good4, float)
+assert_type(ClassA.good5, Any)
 
 
 class BasicStarship:

docs/spec/class-compat.rst

@@ -14,9 +14,6 @@ The :py:data:`typing.ClassVar` :term:`type qualifier` is used to annotate
 class variables that should not be set on class instances. This restriction
 is enforced by static checkers, but not at runtime.
 
-Syntax
-^^^^^^
-
 :py:data:`~typing.ClassVar` may be used in one of several forms:
 
 * With an explicit type, using the syntax ``ClassVar[<type>]``. Example::
@@ -31,14 +28,11 @@ Syntax
         z: ClassVar
 
   If an assigned value is available (e.g. with ``y``), the type should be
-  inferred as some type to which this value is :term:`assignable` (in this
-  case, either ``int``, ``Literal[2]``, or ``Any``).
+  inferred as some type to which this value is :term:`assignable` (for example,
+  ``int``, ``Literal[2]``, or ``Any``).
 
   If the ``ClassVar`` qualifier is used without any assigned value, the type
-  should be inferred to an unknown static type (such as :ref:`Any`).
-
-Semantics and examples
-^^^^^^^^^^^^^^^^^^^^^^
+  should be inferred as :ref:`any`.
 
 Type annotations can be used to annotate class and instance variables
 in class bodies and methods. In particular, the value-less notation ``a: int``