Add section about metaclass constructors

conformance/results/mypy/constructors_class_statements.toml

@@ -0,0 +1,27 @@
+conformant = "Partial"
+notes = """
+Does not honor the evaluated return type of the implied metaclass call when it isn't a class.
+Does not validate keyword arguments in a class statement against the metaclass `__new__` method.
+Incorrectly rejects a metaclass `__new__` method annotated to return a type other than a class.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 56: Expected 1 errors
+Line 60: Expected 1 errors
+Line 77: Unexpected errors ['constructors_class_statements.py:77: error: Incompatible return type for "__new__" (returns "int", but must return a subtype of "type")  [misc]']
+Line 85: Unexpected errors ['constructors_class_statements.py:85: error: Expression is of type "type[Class6]", not "int"  [assert-type]']
+"""
+output = """
+constructors_class_statements.py:30: error: Metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases  [metaclass]
+constructors_class_statements.py:30: note: "constructors_class_statements.MetaA" (metaclass of "constructors_class_statements.BaseA") conflicts with "constructors_class_statements.MetaB" (metaclass of "constructors_class_statements.BaseB")
+constructors_class_statements.py:69: error: Argument "key" to "Meta1" has incompatible type "str"; expected "int"  [arg-type]
+constructors_class_statements.py:77: error: Incompatible return type for "__new__" (returns "int", but must return a subtype of "type")  [misc]
+constructors_class_statements.py:85: error: Expression is of type "type[Class6]", not "int"  [assert-type]
+constructors_class_statements.py:93: error: Signature of "__prepare__" incompatible with supertype "builtins.type"  [override]
+constructors_class_statements.py:93: note:      Superclass:
+constructors_class_statements.py:93: note:          @classmethod
+constructors_class_statements.py:93: note:          def __prepare__(metacls, str, tuple[type, ...], /, **kwds: Any) -> MutableMapping[str, object]
+constructors_class_statements.py:93: note:      Subclass:
+constructors_class_statements.py:93: note:          @classmethod
+constructors_class_statements.py:93: note:          def __prepare__(mcls, name: str, bases: tuple[type, ...]) -> Any
+"""

conformance/results/mypy/constructors_init_subclass.toml

@@ -0,0 +1,13 @@
+conformant = "Partial"
+notes = """
+Does not validate keyword arguments against `__init_subclass__` when the metaclass defines an `__init__` method (but no `__new__` method).
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 58: Expected 1 errors
+"""
+output = """
+constructors_init_subclass.py:26: error: Argument "flag" to "__init_subclass__" of "Base" has incompatible type "str"; expected "bool"  [arg-type]
+constructors_init_subclass.py:30: error: Unexpected keyword argument "other" for "__init_subclass__" of "Base"  [call-arg]
+constructors_init_subclass.py:34: error: Unexpected keyword argument "other" for "__init_subclass__" of "object"  [call-arg]
+"""

conformance/results/mypy/constructors_metaclass.toml

@@ -0,0 +1,19 @@
+conformant = "Partial"
+notes = """
+Does not evaluate the `__call__` method of the metaclass's own metaclass.
+Incorrectly rejects a metaclass `__new__` method annotated to return a type other than a class.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 28: Unexpected errors ['constructors_metaclass.py:28: error: Expression is of type "Meta1", not "Never"  [assert-type]']
+Line 57: Unexpected errors ['constructors_metaclass.py:57: error: Incompatible return type for "__new__" (returns "int", but must return a subtype of "type")  [misc]']
+Line 67: Unexpected errors ['constructors_metaclass.py:67: error: Expression is of type "Meta3", not "int"  [assert-type]', 'constructors_metaclass.py:67: error: Too many arguments for "Meta3"  [call-arg]']
+"""
+output = """
+constructors_metaclass.py:28: error: Expression is of type "Meta1", not "Never"  [assert-type]
+constructors_metaclass.py:47: error: Missing named argument "key" for "Meta2"  [call-arg]
+constructors_metaclass.py:48: error: Argument "key" to "Meta2" has incompatible type "str"; expected "int"  [arg-type]
+constructors_metaclass.py:57: error: Incompatible return type for "__new__" (returns "int", but must return a subtype of "type")  [misc]
+constructors_metaclass.py:67: error: Expression is of type "Meta3", not "int"  [assert-type]
+constructors_metaclass.py:67: error: Too many arguments for "Meta3"  [call-arg]
+"""

conformance/results/mypy/constructors_type_constructor.toml

@@ -0,0 +1,15 @@
+conformant = "Partial"
+notes = """
+Does not report a single-argument call to a subclass of `type`.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 29: Expected 1 errors
+"""
+output = """
+constructors_type_constructor.py:30: error: No overload variant of "type" matches argument types "str", "tuple[()]"  [call-overload]
+constructors_type_constructor.py:30: note: Possible overload variants:
+constructors_type_constructor.py:30: note:     def type(object, /) -> type
+constructors_type_constructor.py:30: note:     def type(str, tuple[type, ...], dict[str, Any], /, **kwds: Any) -> type
+constructors_type_constructor.py:52: error: Argument 1 to "MetaSingle" has incompatible type "str"; expected "int"  [arg-type]
+"""

conformance/results/pycroscope/constructors_class_statements.toml

@@ -0,0 +1,16 @@
+conformant = "Partial"
+notes = """
+Does not honor the evaluated return type of the implied metaclass call when it isn't a class.
+Does not validate keyword arguments in a class statement against the metaclass `__new__` method.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 56: Expected 1 errors
+Line 60: Expected 1 errors
+Line 85: Unexpected errors ["./constructors_class_statements.py:85:12:   <class 'Class6'> is not equivalent to int"]
+"""
+output = """
+./constructors_class_statements.py:69:28: Incompatible argument type for key: expected int but got Literal[''] [incompatible_argument]
+./constructors_class_statements.py:85:12:   <class 'Class6'> is not equivalent to int
+./constructors_class_statements.py:93:4: Value of __prepare__ incompatible with base class type [incompatible_override]
+"""

conformance/results/pycroscope/constructors_init_subclass.toml

@@ -0,0 +1,17 @@
+conformant = "Partial"
+notes = """
+Does not validate class statement keyword arguments against `__init_subclass__`.
+Incorrectly rejects a call to `type` with three positional arguments and additional keyword arguments.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 26: Expected 1 errors
+Line 30: Expected 1 errors
+Line 34: Expected 1 errors
+Line 58: Expected 1 errors
+Line 67: Unexpected errors ['./constructors_init_subclass.py:67:0: Cannot call overloaded function [incompatible_call]']
+"""
+output = """
+./constructors_init_subclass.py:67:0: Cannot call overloaded function [incompatible_call]
+./constructors_init_subclass.py:68:0: Cannot call overloaded function [incompatible_call]
+"""

conformance/results/pycroscope/constructors_metaclass.toml

@@ -0,0 +1,8 @@
+conformant = "Pass"
+conformance_automated = "Pass"
+errors_diff = """
+"""
+output = """
+./constructors_metaclass.py:47:0: Missing required argument 'key' [incompatible_call]
+./constructors_metaclass.py:48:23: Incompatible argument type for key: expected int but got Literal[''] [incompatible_argument]
+"""

conformance/results/pycroscope/constructors_type_constructor.toml

@@ -0,0 +1,15 @@
+conformant = "Partial"
+notes = """
+Does not report a single-argument call to a subclass of `type`.
+Does not evaluate the result of a single-argument call to `type` as `type[T]`.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 29: Expected 1 errors
+Line 28: Unexpected errors ["./constructors_type_constructor.py:28:12:   type 'int' is not equivalent to type[int]"]
+"""
+output = """
+./constructors_type_constructor.py:28:12:   type 'int' is not equivalent to type[int]
+./constructors_type_constructor.py:30:0: Cannot call overloaded function [incompatible_call]
+./constructors_type_constructor.py:52:11: Incompatible argument type for x: expected int but got Literal[''] [incompatible_argument]
+"""

conformance/results/pyrefly/constructors_class_statements.toml

@@ -0,0 +1,17 @@
+conformant = "Partial"
+notes = """
+Does not honor the evaluated return type of the implied metaclass call when it isn't a class.
+Does not validate keyword arguments in a class statement against the metaclass `__new__` method.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 56: Expected 1 errors
+Line 60: Expected 1 errors
+Line 85: Unexpected errors ['assert_type(type[Class6], int) failed [assert-type]']
+"""
+output = """
+ERROR constructors_class_statements.py:30:7-20: Class `ClassConflict` has metaclass `MetaA` from base class `BaseA` which is not compatible with metaclass `MetaB` from base class `BaseB` [invalid-inheritance]
+ERROR constructors_class_statements.py:69:29-31: Argument `Literal['']` is not assignable to parameter `key` with type `int` in function `Meta1.__new__` [bad-argument-type]
+ERROR constructors_class_statements.py:85:12-25: assert_type(type[Class6], int) failed [assert-type]
+ERROR constructors_class_statements.py:93:9-20: Class member `Meta3.__prepare__` overrides parent class `type` in an inconsistent manner [bad-override]
+"""

conformance/results/pyrefly/constructors_init_subclass.toml

@@ -0,0 +1,14 @@
+conformant = "Partial"
+notes = """
+Does not validate keyword arguments against `object.__init_subclass__` in a class statement with no explicit base classes.
+Does not validate keyword arguments against `__init_subclass__` when the metaclass defines an `__init__` method (but no `__new__` method).
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 34: Expected 1 errors
+Line 58: Expected 1 errors
+"""
+output = """
+ERROR constructors_init_subclass.py:26:25-27: Argument `Literal['']` is not assignable to parameter `flag` with type `bool` in function `Base.__init_subclass__` [bad-argument-type]
+ERROR constructors_init_subclass.py:30:20-25: Unexpected keyword argument `other` in function `Base.__init_subclass__` [unexpected-keyword]
+"""

conformance/results/pyrefly/constructors_metaclass.toml

@@ -0,0 +1,8 @@
+conformant = "Pass"
+conformance_automated = "Pass"
+errors_diff = """
+"""
+output = """
+ERROR constructors_metaclass.py:47:6-19: Missing argument `key` in function `Meta2.__new__` [missing-argument]
+ERROR constructors_metaclass.py:48:24-26: Argument `Literal['']` is not assignable to parameter `key` with type `int` in function `Meta2.__new__` [bad-argument-type]
+"""

conformance/results/pyrefly/constructors_type_constructor.toml

@@ -0,0 +1,12 @@
+conformant = "Partial"
+notes = """
+Does not report a single-argument call to a subclass of `type`.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 29: Expected 1 errors
+"""
+output = """
+ERROR constructors_type_constructor.py:30:5-14: No matching overload found for function `type.__new__` called with arguments: (type[type], Literal['A'], tuple[()]) [no-matching-overload]
+ERROR constructors_type_constructor.py:52:12-14: Argument `Literal['']` is not assignable to parameter `x` with type `int` in function `MetaSingle.__new__` [bad-argument-type]
+"""

conformance/results/pyright/constructors_class_statements.toml

@@ -0,0 +1,20 @@
+conformant = "Partial"
+notes = """
+Does not honor the evaluated return type of the implied metaclass call when it isn't a class.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 85: Unexpected errors ['constructors_class_statements.py:85:13 - error: "assert_type" mismatch: expected "int" but received "type[Class6]" (reportAssertTypeFailure)']
+"""
+output = """
+constructors_class_statements.py:30:7 - error: The metaclass of a derived class must be a subclass of the metaclasses of all its base classes
+  Metaclass "MetaA" conflicts with "MetaB" (reportGeneralTypeIssues)
+constructors_class_statements.py:56:35 - error: Argument of type "Literal['']" cannot be assigned to parameter of type "int" in function "__new__"
+  "Literal['']" is not assignable to "int" (reportArgumentType)
+constructors_class_statements.py:60:7 - error: Argument missing for parameter "key" (reportGeneralTypeIssues)
+constructors_class_statements.py:69:29 - error: Argument of type "Literal['']" cannot be assigned to parameter "key" of type "int" in function "__new__"
+  "Literal['']" is not assignable to "int" (reportArgumentType)
+constructors_class_statements.py:85:13 - error: "assert_type" mismatch: expected "int" but received "type[Class6]" (reportAssertTypeFailure)
+constructors_class_statements.py:93:9 - error: Method "__prepare__" overrides class "type" in an incompatible manner
+  Parameter "**kwds" has no corresponding parameter (reportIncompatibleMethodOverride)
+"""

conformance/results/pyright/constructors_init_subclass.toml

@@ -0,0 +1,15 @@
+conformant = "Pass"
+conformance_automated = "Pass"
+errors_diff = """
+"""
+output = """
+constructors_init_subclass.py:26:7 - error: Incorrect keyword arguments for __init_subclass__ method (reportGeneralTypeIssues)
+constructors_init_subclass.py:26:25 - error: Argument of type "Literal['']" cannot be assigned to parameter "flag" of type "bool" in function "__init_subclass__"
+  "Literal['']" is not assignable to "bool" (reportArgumentType)
+constructors_init_subclass.py:30:7 - error: Incorrect keyword arguments for __init_subclass__ method (reportGeneralTypeIssues)
+constructors_init_subclass.py:30:20 - error: No parameter named "other" (reportCallIssue)
+constructors_init_subclass.py:34:7 - error: Incorrect keyword arguments for __init_subclass__ method (reportGeneralTypeIssues)
+constructors_init_subclass.py:34:14 - error: No parameter named "other" (reportCallIssue)
+constructors_init_subclass.py:58:7 - error: Incorrect keyword arguments for __init_subclass__ method (reportGeneralTypeIssues)
+constructors_init_subclass.py:58:40 - error: No parameter named "key" (reportCallIssue)
+"""

conformance/results/pyright/constructors_metaclass.toml

@@ -0,0 +1,9 @@
+conformant = "Pass"
+conformance_automated = "Pass"
+errors_diff = """
+"""
+output = """
+constructors_metaclass.py:47:1 - error: Argument missing for parameter "key" (reportCallIssue)
+constructors_metaclass.py:48:24 - error: Argument of type "Literal['']" cannot be assigned to parameter "key" of type "int" in function "__new__"
+  "Literal['']" is not assignable to "int" (reportArgumentType)
+"""

conformance/results/pyright/constructors_type_constructor.toml

@@ -0,0 +1,16 @@
+conformant = "Partial"
+notes = """
+Does not report a single-argument call to a subclass of `type`.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 29: Expected 1 errors
+"""
+output = """
+constructors_type_constructor.py:30:1 - error: No overloads for "__new__" match the provided arguments
+  Argument types: (Literal['A'], tuple[()]) (reportCallIssue)
+constructors_type_constructor.py:30:1 - error: No overloads for "__init__" match the provided arguments
+  Argument types: (Literal['A'], tuple[()]) (reportCallIssue)
+constructors_type_constructor.py:52:12 - error: Argument of type "Literal['']" cannot be assigned to parameter "x" of type "int" in function "__new__"
+  "Literal['']" is not assignable to "int" (reportArgumentType)
+"""