diff --git a/conformance/results/mypy/dataclasses_usage.toml b/conformance/results/mypy/dataclasses_usage.toml
index 978642d0..25f6f302 100644
--- a/conformance/results/mypy/dataclasses_usage.toml
+++ b/conformance/results/mypy/dataclasses_usage.toml
@@ -3,18 +3,19 @@ notes = """
 Does not detect unannotated usage of `dataclasses.field()`.
 """
 output = """
-dataclasses_usage.py:35: error: Accessing "__init__" on an instance is unsound, since instance.__init__ could be from an incompatible subclass  [misc]
-dataclasses_usage.py:50: error: Missing positional argument "unit_price" in call to "InventoryItem"  [call-arg]
-dataclasses_usage.py:51: error: Argument 2 to "InventoryItem" has incompatible type "str"; expected "float"  [arg-type]
-dataclasses_usage.py:52: error: Too many arguments for "InventoryItem"  [call-arg]
-dataclasses_usage.py:61: error: Attributes without a default cannot follow attributes with one  [misc]
-dataclasses_usage.py:67: error: Attributes without a default cannot follow attributes with one  [misc]
-dataclasses_usage.py:73: error: Attributes without a default cannot follow attributes with one  [misc]
-dataclasses_usage.py:83: error: Too many arguments for "DC4"  [call-arg]
-dataclasses_usage.py:88: error: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]
-dataclasses_usage.py:127: error: Too many arguments for "DC7"  [call-arg]
-dataclasses_usage.py:130: error: Missing positional argument "y" in call to "DC8"  [call-arg]
-dataclasses_usage.py:179: error: Too many arguments for "DC13"  [call-arg]
+dataclasses_usage.py:36: error: Accessing "__init__" on an instance is unsound, since instance.__init__ could be from an incompatible subclass  [misc]
+dataclasses_usage.py:51: error: Missing positional argument "unit_price" in call to "InventoryItem"  [call-arg]
+dataclasses_usage.py:52: error: Argument 2 to "InventoryItem" has incompatible type "str"; expected "float"  [arg-type]
+dataclasses_usage.py:53: error: Too many arguments for "InventoryItem"  [call-arg]
+dataclasses_usage.py:62: error: Attributes without a default cannot follow attributes with one  [misc]
+dataclasses_usage.py:68: error: Attributes without a default cannot follow attributes with one  [misc]
+dataclasses_usage.py:74: error: Attributes without a default cannot follow attributes with one  [misc]
+dataclasses_usage.py:84: error: Too many arguments for "DC4"  [call-arg]
+dataclasses_usage.py:89: error: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]
+dataclasses_usage.py:128: error: Too many arguments for "DC7"  [call-arg]
+dataclasses_usage.py:131: error: Missing positional argument "y" in call to "DC8"  [call-arg]
+dataclasses_usage.py:180: error: Too many arguments for "DC13"  [call-arg]
+dataclasses_usage.py:246: error: Too many arguments for "DC19"  [call-arg]
 """
 conformance_automated = "Pass"
 errors_diff = """
diff --git a/conformance/results/mypy/enums_definition.toml b/conformance/results/mypy/enums_definition.toml
index 513dbe85..06368c88 100644
--- a/conformance/results/mypy/enums_definition.toml
+++ b/conformance/results/mypy/enums_definition.toml
@@ -2,5 +2,6 @@ conformant = "Pass"
 errors_diff = """
 """
 output = """
+enums_definition.py:92: error: "type[Color12]" has no attribute "BLUE"  [attr-defined]
 """
 conformance_automated = "Pass"
diff --git a/conformance/results/mypy/namedtuples_define_class.toml b/conformance/results/mypy/namedtuples_define_class.toml
index 575c5c0c..12c4dc55 100644
--- a/conformance/results/mypy/namedtuples_define_class.toml
+++ b/conformance/results/mypy/namedtuples_define_class.toml
@@ -1,29 +1,37 @@
 conformant = "Partial"
 notes = """
 Does not reject override of named tuple attribute in child class.
+Does not support version-conditional fields.
 """
 output = """
-namedtuples_define_class.py:32: error: Tuple index out of range  [misc]
 namedtuples_define_class.py:33: error: Tuple index out of range  [misc]
-namedtuples_define_class.py:44: error: Missing positional argument "y" in call to "Point"  [call-arg]
+namedtuples_define_class.py:34: error: Tuple index out of range  [misc]
 namedtuples_define_class.py:45: error: Missing positional argument "y" in call to "Point"  [call-arg]
-namedtuples_define_class.py:46: error: Argument 2 to "Point" has incompatible type "str"; expected "int"  [arg-type]
-namedtuples_define_class.py:47: error: Argument "units" to "Point" has incompatible type "int"; expected "str"  [arg-type]
-namedtuples_define_class.py:48: error: Too many arguments for "Point"  [call-arg]
-namedtuples_define_class.py:49: error: Unexpected keyword argument "other" for "Point"  [call-arg]
-namedtuples_define_class.py:59: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]
-namedtuples_define_class.py:65: error: Missing positional argument "units" in call to "Point2"  [call-arg]
-namedtuples_define_class.py:67: error: Too many values to unpack (2 expected, 3 provided)  [misc]
-namedtuples_define_class.py:76: error: NamedTuple field name cannot start with an underscore: _y  [misc]
-namedtuples_define_class.py:86: error: Non-default NamedTuple fields cannot follow default fields  [misc]
-namedtuples_define_class.py:125: error: Argument 2 to "Property" has incompatible type "float"; expected "str"  [arg-type]
-namedtuples_define_class.py:132: error: NamedTuple should be a single base  [misc]
+namedtuples_define_class.py:46: error: Missing positional argument "y" in call to "Point"  [call-arg]
+namedtuples_define_class.py:47: error: Argument 2 to "Point" has incompatible type "str"; expected "int"  [arg-type]
+namedtuples_define_class.py:48: error: Argument "units" to "Point" has incompatible type "int"; expected "str"  [arg-type]
+namedtuples_define_class.py:49: error: Too many arguments for "Point"  [call-arg]
+namedtuples_define_class.py:50: error: Unexpected keyword argument "other" for "Point"  [call-arg]
+namedtuples_define_class.py:60: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]
+namedtuples_define_class.py:66: error: Missing positional argument "units" in call to "Point2"  [call-arg]
+namedtuples_define_class.py:68: error: Too many values to unpack (2 expected, 3 provided)  [misc]
+namedtuples_define_class.py:77: error: NamedTuple field name cannot start with an underscore: _y  [misc]
+namedtuples_define_class.py:87: error: Non-default NamedTuple fields cannot follow default fields  [misc]
+namedtuples_define_class.py:114: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]
+namedtuples_define_class.py:116: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]
+namedtuples_define_class.py:120: error: Too many arguments for "ConditionalField"  [call-arg]
+namedtuples_define_class.py:121: error: Too many arguments for "ConditionalField"  [call-arg]
+namedtuples_define_class.py:140: error: Argument 2 to "Property" has incompatible type "float"; expected "str"  [arg-type]
+namedtuples_define_class.py:147: error: NamedTuple should be a single base  [misc]
 """
 conformance_automated = "Fail"
 errors_diff = """
-Line 69: Expected 1 errors
-Line 106: Expected 1 errors
-Line 59: Unexpected errors ['namedtuples_define_class.py:59: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]']
-Line 65: Unexpected errors ['namedtuples_define_class.py:65: error: Missing positional argument "units" in call to "Point2"  [call-arg]']
-Line 67: Unexpected errors ['namedtuples_define_class.py:67: error: Too many values to unpack (2 expected, 3 provided)  [misc]']
+Line 70: Expected 1 errors
+Line 107: Expected 1 errors
+Line 60: Unexpected errors ['namedtuples_define_class.py:60: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]']
+Line 66: Unexpected errors ['namedtuples_define_class.py:66: error: Missing positional argument "units" in call to "Point2"  [call-arg]']
+Line 68: Unexpected errors ['namedtuples_define_class.py:68: error: Too many values to unpack (2 expected, 3 provided)  [misc]']
+Line 114: Unexpected errors ['namedtuples_define_class.py:114: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]']
+Line 116: Unexpected errors ['namedtuples_define_class.py:116: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]']
+Line 120: Unexpected errors ['namedtuples_define_class.py:120: error: Too many arguments for "ConditionalField"  [call-arg]']
 """
diff --git a/conformance/results/mypy/typeddicts_class_syntax.toml b/conformance/results/mypy/typeddicts_class_syntax.toml
index 76e44ef9..29220811 100644
--- a/conformance/results/mypy/typeddicts_class_syntax.toml
+++ b/conformance/results/mypy/typeddicts_class_syntax.toml
@@ -1,11 +1,21 @@
-conformant = "Pass"
+conformant = "Partial"
+notes = """
+Does not support version-conditional items in TypedDict definitions.
+"""
 output = """
-typeddicts_class_syntax.py:29: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
-typeddicts_class_syntax.py:33: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
-typeddicts_class_syntax.py:38: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
-typeddicts_class_syntax.py:44: error: Unexpected keyword argument "metaclass" for "__init_subclass__" of "TypedDict"  [call-arg]
-typeddicts_class_syntax.py:49: error: Unexpected keyword argument "other" for "__init_subclass__" of "TypedDict"  [call-arg]
+typeddicts_class_syntax.py:30: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:34: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:39: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:45: error: Unexpected keyword argument "metaclass" for "__init_subclass__" of "TypedDict"  [call-arg]
+typeddicts_class_syntax.py:50: error: Unexpected keyword argument "other" for "__init_subclass__" of "TypedDict"  [call-arg]
+typeddicts_class_syntax.py:58: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:60: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:64: error: Extra key "y" for TypedDict "ConditionalField"  [typeddict-unknown-key]
+typeddicts_class_syntax.py:65: error: Extra keys ("y", "z") for TypedDict "ConditionalField"  [typeddict-unknown-key]
 """
-conformance_automated = "Pass"
+conformance_automated = "Fail"
 errors_diff = """
+Line 58: Unexpected errors ['typeddicts_class_syntax.py:58: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]']
+Line 60: Unexpected errors ['typeddicts_class_syntax.py:60: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]']
+Line 64: Unexpected errors ['typeddicts_class_syntax.py:64: error: Extra key "y" for TypedDict "ConditionalField"  [typeddict-unknown-key]']
 """
diff --git a/conformance/results/pyrefly/dataclasses_usage.toml b/conformance/results/pyrefly/dataclasses_usage.toml
index c8156fc6..a289244a 100644
--- a/conformance/results/pyrefly/dataclasses_usage.toml
+++ b/conformance/results/pyrefly/dataclasses_usage.toml
@@ -3,15 +3,16 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-ERROR dataclasses_usage.py:50:19-27: Missing argument `unit_price` in function `InventoryItem.__init__` [missing-argument]
-ERROR dataclasses_usage.py:51:28-35: Argument `Literal['price']` is not assignable to parameter `unit_price` with type `float` in function `InventoryItem.__init__` [bad-argument-type]
-ERROR dataclasses_usage.py:52:36-37: Expected 3 positional arguments, got 4 in function `InventoryItem.__init__` [bad-argument-count]
-ERROR dataclasses_usage.py:61:5-6: Dataclass field `b` without a default may not follow dataclass field with a default [bad-class-definition]
-ERROR dataclasses_usage.py:67:5-6: Dataclass field `b` without a default may not follow dataclass field with a default [bad-class-definition]
-ERROR dataclasses_usage.py:73:5-6: Dataclass field `b` without a default may not follow dataclass field with a default [bad-class-definition]
-ERROR dataclasses_usage.py:83:13-14: Expected 1 positional argument, got 2 in function `DC4.__init__` [bad-argument-count]
-ERROR dataclasses_usage.py:88:14-40: `str` is not assignable to `int` [bad-assignment]
-ERROR dataclasses_usage.py:127:8-9: Expected 1 positional argument, got 2 in function `DC7.__init__` [bad-argument-count]
-ERROR dataclasses_usage.py:130:4-7: Missing argument `y` in function `DC8.__init__` [missing-argument]
-ERROR dataclasses_usage.py:179:6-7: Expected 0 positional arguments, got 1 in function `object.__init__` [bad-argument-count]
+ERROR dataclasses_usage.py:51:19-27: Missing argument `unit_price` in function `InventoryItem.__init__` [missing-argument]
+ERROR dataclasses_usage.py:52:28-35: Argument `Literal['price']` is not assignable to parameter `unit_price` with type `float` in function `InventoryItem.__init__` [bad-argument-type]
+ERROR dataclasses_usage.py:53:36-37: Expected 3 positional arguments, got 4 in function `InventoryItem.__init__` [bad-argument-count]
+ERROR dataclasses_usage.py:62:5-6: Dataclass field `b` without a default may not follow dataclass field with a default [bad-class-definition]
+ERROR dataclasses_usage.py:68:5-6: Dataclass field `b` without a default may not follow dataclass field with a default [bad-class-definition]
+ERROR dataclasses_usage.py:74:5-6: Dataclass field `b` without a default may not follow dataclass field with a default [bad-class-definition]
+ERROR dataclasses_usage.py:84:13-14: Expected 1 positional argument, got 2 in function `DC4.__init__` [bad-argument-count]
+ERROR dataclasses_usage.py:89:14-40: `str` is not assignable to `int` [bad-assignment]
+ERROR dataclasses_usage.py:128:8-9: Expected 1 positional argument, got 2 in function `DC7.__init__` [bad-argument-count]
+ERROR dataclasses_usage.py:131:4-7: Missing argument `y` in function `DC8.__init__` [missing-argument]
+ERROR dataclasses_usage.py:180:6-7: Expected 0 positional arguments, got 1 in function `object.__init__` [bad-argument-count]
+ERROR dataclasses_usage.py:246:12-13: Expected 2 positional arguments, got 3 in function `DC19.__init__` [bad-argument-count]
 """
diff --git a/conformance/results/pyrefly/enums_definition.toml b/conformance/results/pyrefly/enums_definition.toml
index be211bd5..22ed73f5 100644
--- a/conformance/results/pyrefly/enums_definition.toml
+++ b/conformance/results/pyrefly/enums_definition.toml
@@ -3,4 +3,5 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
+ERROR enums_definition.py:92:1-13: Class `Color12` has no class attribute `BLUE` [missing-attribute]
 """
diff --git a/conformance/results/pyrefly/namedtuples_define_class.toml b/conformance/results/pyrefly/namedtuples_define_class.toml
index 706bce8f..e98b6c71 100644
--- a/conformance/results/pyrefly/namedtuples_define_class.toml
+++ b/conformance/results/pyrefly/namedtuples_define_class.toml
@@ -3,18 +3,19 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-ERROR namedtuples_define_class.py:32:10-11: Index 3 out of range for tuple with 3 elements [bad-index]
-ERROR namedtuples_define_class.py:33:10-12: Index -4 out of range for tuple with 3 elements [bad-index]
-ERROR namedtuples_define_class.py:44:11-14: Missing argument `y` in function `Point.__new__` [missing-argument]
-ERROR namedtuples_define_class.py:45:11-16: Missing argument `y` in function `Point.__new__` [missing-argument]
-ERROR namedtuples_define_class.py:46:15-17: Argument `Literal['']` is not assignable to parameter `y` with type `int` in function `Point.__new__` [bad-argument-type]
-ERROR namedtuples_define_class.py:47:24-25: Argument `Literal[3]` is not assignable to parameter `units` with type `str` in function `Point.__new__` [bad-argument-type]
-ERROR namedtuples_define_class.py:48:22-24: Expected 3 positional arguments, got 4 in function `Point.__new__` [bad-argument-count]
-ERROR namedtuples_define_class.py:49:23-28: Unexpected keyword argument `other` in function `Point.__new__` [unexpected-keyword]
-ERROR namedtuples_define_class.py:69:20-22: Expected 2 positional arguments, got 3 in function `Point2.__new__` [bad-argument-count]
-ERROR namedtuples_define_class.py:76:5-7: NamedTuple field name may not start with an underscore: `_y` [bad-class-definition]
-ERROR namedtuples_define_class.py:86:5-13: NamedTuple field 'latitude' without a default may not follow NamedTuple field with a default [bad-class-definition]
-ERROR namedtuples_define_class.py:106:5-6: Cannot override named tuple element `x` [bad-override]
-ERROR namedtuples_define_class.py:125:19-22: Argument `float` is not assignable to parameter `value` with type `str` in function `Property.__new__` [bad-argument-type]
-ERROR namedtuples_define_class.py:132:7-11: Named tuples do not support multiple inheritance [invalid-inheritance]
+ERROR namedtuples_define_class.py:33:10-11: Index 3 out of range for tuple with 3 elements [bad-index]
+ERROR namedtuples_define_class.py:34:10-12: Index -4 out of range for tuple with 3 elements [bad-index]
+ERROR namedtuples_define_class.py:45:11-14: Missing argument `y` in function `Point.__new__` [missing-argument]
+ERROR namedtuples_define_class.py:46:11-16: Missing argument `y` in function `Point.__new__` [missing-argument]
+ERROR namedtuples_define_class.py:47:15-17: Argument `Literal['']` is not assignable to parameter `y` with type `int` in function `Point.__new__` [bad-argument-type]
+ERROR namedtuples_define_class.py:48:24-25: Argument `Literal[3]` is not assignable to parameter `units` with type `str` in function `Point.__new__` [bad-argument-type]
+ERROR namedtuples_define_class.py:49:22-24: Expected 3 positional arguments, got 4 in function `Point.__new__` [bad-argument-count]
+ERROR namedtuples_define_class.py:50:23-28: Unexpected keyword argument `other` in function `Point.__new__` [unexpected-keyword]
+ERROR namedtuples_define_class.py:70:20-22: Expected 2 positional arguments, got 3 in function `Point2.__new__` [bad-argument-count]
+ERROR namedtuples_define_class.py:77:5-7: NamedTuple field name may not start with an underscore: `_y` [bad-class-definition]
+ERROR namedtuples_define_class.py:87:5-13: NamedTuple field 'latitude' without a default may not follow NamedTuple field with a default [bad-class-definition]
+ERROR namedtuples_define_class.py:107:5-6: Cannot override named tuple element `x` [bad-override]
+ERROR namedtuples_define_class.py:121:24-25: Expected 2 positional arguments, got 3 in function `ConditionalField.__new__` [bad-argument-count]
+ERROR namedtuples_define_class.py:140:19-22: Argument `float` is not assignable to parameter `value` with type `str` in function `Property.__new__` [bad-argument-type]
+ERROR namedtuples_define_class.py:147:7-11: Named tuples do not support multiple inheritance [invalid-inheritance]
 """
diff --git a/conformance/results/pyrefly/typeddicts_class_syntax.toml b/conformance/results/pyrefly/typeddicts_class_syntax.toml
index 6e367e6d..2917003c 100644
--- a/conformance/results/pyrefly/typeddicts_class_syntax.toml
+++ b/conformance/results/pyrefly/typeddicts_class_syntax.toml
@@ -3,9 +3,10 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-ERROR typeddicts_class_syntax.py:29:9-16: TypedDict members must be declared in the form `field: Annotation` with no assignment [bad-class-definition]
-ERROR typeddicts_class_syntax.py:34:9-16: TypedDict members must be declared in the form `field: Annotation` with no assignment [bad-class-definition]
-ERROR typeddicts_class_syntax.py:39:9-16: TypedDict members must be declared in the form `field: Annotation` with no assignment [bad-class-definition]
-ERROR typeddicts_class_syntax.py:44:7-20: Metaclass of `BadTypedDict2` has type `type[Any]` that is not a simple class type [invalid-inheritance]
-ERROR typeddicts_class_syntax.py:49:7-20: TypedDict does not support keyword argument `other` [bad-typed-dict]
+ERROR typeddicts_class_syntax.py:30:9-16: TypedDict members must be declared in the form `field: Annotation` with no assignment [bad-class-definition]
+ERROR typeddicts_class_syntax.py:35:9-16: TypedDict members must be declared in the form `field: Annotation` with no assignment [bad-class-definition]
+ERROR typeddicts_class_syntax.py:40:9-16: TypedDict members must be declared in the form `field: Annotation` with no assignment [bad-class-definition]
+ERROR typeddicts_class_syntax.py:45:7-20: Metaclass of `BadTypedDict2` has type `type[Any]` that is not a simple class type [invalid-inheritance]
+ERROR typeddicts_class_syntax.py:50:7-20: TypedDict does not support keyword argument `other` [bad-typed-dict]
+ERROR typeddicts_class_syntax.py:65:17-32: No matching overload found for function `ConditionalField.__init__` called with arguments: (x=Literal[1], y=Literal[2], z=Literal[3]) [no-matching-overload]
 """
diff --git a/conformance/results/pyright/dataclasses_usage.toml b/conformance/results/pyright/dataclasses_usage.toml
index 67ec33f2..62d5a0cb 100644
--- a/conformance/results/pyright/dataclasses_usage.toml
+++ b/conformance/results/pyright/dataclasses_usage.toml
@@ -1,19 +1,20 @@
 conformant = "Pass"
 output = """
-dataclasses_usage.py:50:6 - error: Argument missing for parameter "unit_price" (reportCallIssue)
-dataclasses_usage.py:51:28 - error: Argument of type "Literal['price']" cannot be assigned to parameter "unit_price" of type "float" in function "__init__"
+dataclasses_usage.py:51:6 - error: Argument missing for parameter "unit_price" (reportCallIssue)
+dataclasses_usage.py:52:28 - error: Argument of type "Literal['price']" cannot be assigned to parameter "unit_price" of type "float" in function "__init__"
   "Literal['price']" is not assignable to "float" (reportArgumentType)
-dataclasses_usage.py:52:36 - error: Expected 3 positional arguments (reportCallIssue)
-dataclasses_usage.py:61:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
-dataclasses_usage.py:67:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
-dataclasses_usage.py:73:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
-dataclasses_usage.py:83:13 - error: Expected 1 positional argument (reportCallIssue)
-dataclasses_usage.py:88:14 - error: Type "str" is not assignable to declared type "int"
+dataclasses_usage.py:53:36 - error: Expected 3 positional arguments (reportCallIssue)
+dataclasses_usage.py:62:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
+dataclasses_usage.py:68:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
+dataclasses_usage.py:74:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
+dataclasses_usage.py:84:13 - error: Expected 1 positional argument (reportCallIssue)
+dataclasses_usage.py:89:14 - error: Type "str" is not assignable to declared type "int"
   "str" is not assignable to "int" (reportAssignmentType)
-dataclasses_usage.py:127:8 - error: Expected 1 positional argument (reportCallIssue)
-dataclasses_usage.py:130:1 - error: Argument missing for parameter "y" (reportCallIssue)
-dataclasses_usage.py:179:6 - error: Expected 0 positional arguments (reportCallIssue)
-dataclasses_usage.py:228:9 - error: Dataclass field without type annotation will cause runtime exception (reportGeneralTypeIssues)
+dataclasses_usage.py:128:8 - error: Expected 1 positional argument (reportCallIssue)
+dataclasses_usage.py:131:1 - error: Argument missing for parameter "y" (reportCallIssue)
+dataclasses_usage.py:180:6 - error: Expected 0 positional arguments (reportCallIssue)
+dataclasses_usage.py:229:9 - error: Dataclass field without type annotation will cause runtime exception (reportGeneralTypeIssues)
+dataclasses_usage.py:246:12 - error: Expected 2 positional arguments (reportCallIssue)
 """
 conformance_automated = "Pass"
 errors_diff = """
diff --git a/conformance/results/pyright/enums_definition.toml b/conformance/results/pyright/enums_definition.toml
index 513dbe85..6741494f 100644
--- a/conformance/results/pyright/enums_definition.toml
+++ b/conformance/results/pyright/enums_definition.toml
@@ -2,5 +2,7 @@ conformant = "Pass"
 errors_diff = """
 """
 output = """
+enums_definition.py:92:9 - error: Cannot access attribute "BLUE" for class "type[Color12]"
+  Attribute "BLUE" is unknown (reportAttributeAccessIssue)
 """
 conformance_automated = "Pass"
diff --git a/conformance/results/pyright/namedtuples_define_class.toml b/conformance/results/pyright/namedtuples_define_class.toml
index e04b26fc..59049fa4 100644
--- a/conformance/results/pyright/namedtuples_define_class.toml
+++ b/conformance/results/pyright/namedtuples_define_class.toml
@@ -1,22 +1,23 @@
 conformant = "Pass"
 output = """
-namedtuples_define_class.py:32:7 - error: Index 3 is out of range for type Point (reportGeneralTypeIssues)
-namedtuples_define_class.py:33:7 - error: Index -4 is out of range for type Point (reportGeneralTypeIssues)
-namedtuples_define_class.py:44:6 - error: Argument missing for parameter "y" (reportCallIssue)
+namedtuples_define_class.py:33:7 - error: Index 3 is out of range for type Point (reportGeneralTypeIssues)
+namedtuples_define_class.py:34:7 - error: Index -4 is out of range for type Point (reportGeneralTypeIssues)
 namedtuples_define_class.py:45:6 - error: Argument missing for parameter "y" (reportCallIssue)
-namedtuples_define_class.py:46:15 - error: Argument of type "Literal['']" cannot be assigned to parameter "y" of type "int" in function "__new__"
+namedtuples_define_class.py:46:6 - error: Argument missing for parameter "y" (reportCallIssue)
+namedtuples_define_class.py:47:15 - error: Argument of type "Literal['']" cannot be assigned to parameter "y" of type "int" in function "__new__"
   "Literal['']" is not assignable to "int" (reportArgumentType)
-namedtuples_define_class.py:47:24 - error: Argument of type "Literal[3]" cannot be assigned to parameter "units" of type "str" in function "__new__"
+namedtuples_define_class.py:48:24 - error: Argument of type "Literal[3]" cannot be assigned to parameter "units" of type "str" in function "__new__"
   "Literal[3]" is not assignable to "str" (reportArgumentType)
-namedtuples_define_class.py:48:22 - error: Expected 3 positional arguments (reportCallIssue)
-namedtuples_define_class.py:49:23 - error: No parameter named "other" (reportCallIssue)
-namedtuples_define_class.py:69:20 - error: Expected 2 positional arguments (reportCallIssue)
-namedtuples_define_class.py:76:5 - error: Named tuple field names cannot start with an underscore (reportGeneralTypeIssues)
-namedtuples_define_class.py:86:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
-namedtuples_define_class.py:106:5 - error: Cannot override "x" because parent class "Point" is a named tuple (reportIncompatibleVariableOverride)
-namedtuples_define_class.py:125:19 - error: Argument of type "float" cannot be assigned to parameter "value" of type "str" in function "__new__"
+namedtuples_define_class.py:49:22 - error: Expected 3 positional arguments (reportCallIssue)
+namedtuples_define_class.py:50:23 - error: No parameter named "other" (reportCallIssue)
+namedtuples_define_class.py:70:20 - error: Expected 2 positional arguments (reportCallIssue)
+namedtuples_define_class.py:77:5 - error: Named tuple field names cannot start with an underscore (reportGeneralTypeIssues)
+namedtuples_define_class.py:87:5 - error: Fields without default values cannot appear after fields with default values (reportGeneralTypeIssues)
+namedtuples_define_class.py:107:5 - error: Cannot override "x" because parent class "Point" is a named tuple (reportIncompatibleVariableOverride)
+namedtuples_define_class.py:121:24 - error: Expected 2 positional arguments (reportCallIssue)
+namedtuples_define_class.py:140:19 - error: Argument of type "float" cannot be assigned to parameter "value" of type "str" in function "__new__"
   "float" is not assignable to "str" (reportArgumentType)
-namedtuples_define_class.py:132:7 - error: Multiple inheritance with NamedTuple is not supported (reportGeneralTypeIssues)
+namedtuples_define_class.py:147:7 - error: Multiple inheritance with NamedTuple is not supported (reportGeneralTypeIssues)
 """
 conformance_automated = "Pass"
 errors_diff = """
diff --git a/conformance/results/pyright/typeddicts_class_syntax.toml b/conformance/results/pyright/typeddicts_class_syntax.toml
index b518cd64..e77eac4c 100644
--- a/conformance/results/pyright/typeddicts_class_syntax.toml
+++ b/conformance/results/pyright/typeddicts_class_syntax.toml
@@ -1,11 +1,20 @@
-conformant = "Pass"
+conformant = "Partial"
+notes = """
+Does not support version-conditional items in TypedDict definitions.
+"""
 output = """
-typeddicts_class_syntax.py:29:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
-typeddicts_class_syntax.py:33:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
-typeddicts_class_syntax.py:38:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
-typeddicts_class_syntax.py:44:32 - error: TypedDict does not support __init_subclass__ parameter "metaclass" (reportGeneralTypeIssues)
-typeddicts_class_syntax.py:49:32 - error: TypedDict does not support __init_subclass__ parameter "other" (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:30:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:34:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:39:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:45:32 - error: TypedDict does not support __init_subclass__ parameter "metaclass" (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:50:32 - error: TypedDict does not support __init_subclass__ parameter "other" (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:58:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:60:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)
+typeddicts_class_syntax.py:65:1 - error: No overloads for "__init__" match the provided arguments
+  Argument types: (Literal[1], Literal[2], Literal[3]) (reportCallIssue)
 """
-conformance_automated = "Pass"
+conformance_automated = "Fail"
 errors_diff = """
+Line 58: Unexpected errors ['typeddicts_class_syntax.py:58:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)']
+Line 60: Unexpected errors ['typeddicts_class_syntax.py:60:5 - error: TypedDict classes can contain only type annotations (reportGeneralTypeIssues)']
 """
diff --git a/conformance/results/results.html b/conformance/results/results.html
index c8a5d0f5..f34dcbe9 100644
--- a/conformance/results/results.html
+++ b/conformance/results/results.html
@@ -936,9 +936,9 @@ <h3>Python Type System Conformance Test Results</h3>
 <th class="column col2 conformant">Pass</th>
 </tr>
 <tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;typeddicts_class_syntax</th>
-<th class="column col2 conformant">Pass</th>
-<th class="column col2 conformant">Pass</th>
-<th class="column col2 conformant">Pass</th>
+<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not support version-conditional items in TypedDict definitions.</p></span></div></th>
+<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not support version-conditional items in TypedDict definitions.</p></span></div></th>
+<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not support version-conditional items in TypedDict definitions.</p></span></div></th>
 <th class="column col2 conformant">Pass</th>
 <th class="column col2 conformant">Pass</th>
 </tr>
@@ -1054,9 +1054,9 @@ <h3>Python Type System Conformance Test Results</h3>
 <a class="test_group" href="https://typing.readthedocs.io/en/latest/spec/namedtuples.html">Named tuples</a>
 </th></tr>
 <tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;namedtuples_define_class</th>
-<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not reject override of named tuple attribute in child class.</p></span></div></th>
-<th class="column col2 conformant">Pass</th>
+<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not reject override of named tuple attribute in child class.</p><p>Does not support version-conditional fields.</p></span></div></th>
 <th class="column col2 conformant">Pass</th>
+<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not support version-conditional fields in NamedTuple definitions.</p></span></div></th>
 <th class="column col2 conformant">Pass</th>
 <th class="column col2 conformant">Pass</th>
 </tr>
diff --git a/conformance/results/ty/dataclasses_usage.toml b/conformance/results/ty/dataclasses_usage.toml
index 3e80b64b..989dd39f 100644
--- a/conformance/results/ty/dataclasses_usage.toml
+++ b/conformance/results/ty/dataclasses_usage.toml
@@ -2,15 +2,16 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-dataclasses_usage.py:50:6: error[missing-argument] No argument provided for required parameter `unit_price`
-dataclasses_usage.py:51:28: error[invalid-argument-type] Argument is incorrect: Expected `int | float`, found `Literal["price"]`
-dataclasses_usage.py:52:36: error[too-many-positional-arguments] Too many positional arguments: expected 3, got 4
-dataclasses_usage.py:61:5: error[dataclass-field-order] Required field `b` cannot be defined after fields with default values
-dataclasses_usage.py:67:5: error[dataclass-field-order] Required field `b` cannot be defined after fields with default values
-dataclasses_usage.py:73:5: error[dataclass-field-order] Required field `b` cannot be defined after fields with default values
-dataclasses_usage.py:83:13: error[too-many-positional-arguments] Too many positional arguments: expected 1, got 2
-dataclasses_usage.py:88:14: error[invalid-assignment] Object of type `dataclasses.Field[str]` is not assignable to `int`
-dataclasses_usage.py:127:8: error[too-many-positional-arguments] Too many positional arguments: expected 1, got 2
-dataclasses_usage.py:130:1: error[missing-argument] No argument provided for required parameter `y` of `DC8.__init__`
-dataclasses_usage.py:179:6: error[too-many-positional-arguments] Too many positional arguments to `object.__init__`: expected 1, got 2
+dataclasses_usage.py:51:6: error[missing-argument] No argument provided for required parameter `unit_price`
+dataclasses_usage.py:52:28: error[invalid-argument-type] Argument is incorrect: Expected `int | float`, found `Literal["price"]`
+dataclasses_usage.py:53:36: error[too-many-positional-arguments] Too many positional arguments: expected 3, got 4
+dataclasses_usage.py:62:5: error[dataclass-field-order] Required field `b` cannot be defined after fields with default values
+dataclasses_usage.py:68:5: error[dataclass-field-order] Required field `b` cannot be defined after fields with default values
+dataclasses_usage.py:74:5: error[dataclass-field-order] Required field `b` cannot be defined after fields with default values
+dataclasses_usage.py:84:13: error[too-many-positional-arguments] Too many positional arguments: expected 1, got 2
+dataclasses_usage.py:89:14: error[invalid-assignment] Object of type `dataclasses.Field[str]` is not assignable to `int`
+dataclasses_usage.py:128:8: error[too-many-positional-arguments] Too many positional arguments: expected 1, got 2
+dataclasses_usage.py:131:1: error[missing-argument] No argument provided for required parameter `y` of `DC8.__init__`
+dataclasses_usage.py:180:6: error[too-many-positional-arguments] Too many positional arguments to `object.__init__`: expected 1, got 2
+dataclasses_usage.py:246:12: error[too-many-positional-arguments] Too many positional arguments: expected 2, got 3
 """
diff --git a/conformance/results/ty/enums_definition.toml b/conformance/results/ty/enums_definition.toml
index f857c518..09271fcd 100644
--- a/conformance/results/ty/enums_definition.toml
+++ b/conformance/results/ty/enums_definition.toml
@@ -2,6 +2,7 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-enums_definition.py:24:32: error[too-many-positional-arguments] Too many positional arguments to function `Enum`: expected 2, got 4
-enums_definition.py:33:33: error[invalid-type-form] Type arguments for `Literal` must be `None`, a literal value (int, bool, str, or bytes), or an enum member
+enums_definition.py:25:32: error[too-many-positional-arguments] Too many positional arguments to function `Enum`: expected 2, got 4
+enums_definition.py:34:33: error[invalid-type-form] Type arguments for `Literal` must be `None`, a literal value (int, bool, str, or bytes), or an enum member
+enums_definition.py:92:1: error[unresolved-attribute] Class `Color12` has no attribute `BLUE`
 """
diff --git a/conformance/results/ty/namedtuples_define_class.toml b/conformance/results/ty/namedtuples_define_class.toml
index fdf613b7..e5e7bc78 100644
--- a/conformance/results/ty/namedtuples_define_class.toml
+++ b/conformance/results/ty/namedtuples_define_class.toml
@@ -2,18 +2,19 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-namedtuples_define_class.py:32:7: error[index-out-of-bounds] Index 3 is out of bounds for tuple `Point` with length 3
-namedtuples_define_class.py:33:7: error[index-out-of-bounds] Index -4 is out of bounds for tuple `Point` with length 3
-namedtuples_define_class.py:44:6: error[missing-argument] No argument provided for required parameter `y`
+namedtuples_define_class.py:33:7: error[index-out-of-bounds] Index 3 is out of bounds for tuple `Point` with length 3
+namedtuples_define_class.py:34:7: error[index-out-of-bounds] Index -4 is out of bounds for tuple `Point` with length 3
 namedtuples_define_class.py:45:6: error[missing-argument] No argument provided for required parameter `y`
-namedtuples_define_class.py:46:15: error[invalid-argument-type] Argument is incorrect: Expected `int`, found `Literal[""]`
-namedtuples_define_class.py:47:18: error[invalid-argument-type] Argument is incorrect: Expected `str`, found `Literal[3]`
-namedtuples_define_class.py:48:22: error[too-many-positional-arguments] Too many positional arguments: expected 4, got 5
-namedtuples_define_class.py:49:23: error[unknown-argument] Argument `other` does not match any known parameter
-namedtuples_define_class.py:69:20: error[too-many-positional-arguments] Too many positional arguments: expected 3, got 4
-namedtuples_define_class.py:76:5: error[invalid-named-tuple] NamedTuple field `_y` cannot start with an underscore
-namedtuples_define_class.py:86:5: error[invalid-named-tuple] NamedTuple field without default value cannot follow field(s) with default value(s): Field `latitude` defined here without a default value
-namedtuples_define_class.py:106:5: error[invalid-named-tuple-override] Cannot override NamedTuple field `x` inherited from `Point`
-namedtuples_define_class.py:125:19: error[invalid-argument-type] Argument is incorrect: Expected `str`, found `float`
-namedtuples_define_class.py:132:24: error[invalid-named-tuple] NamedTuple class `Unit` cannot use multiple inheritance except with `Generic[]`
+namedtuples_define_class.py:46:6: error[missing-argument] No argument provided for required parameter `y`
+namedtuples_define_class.py:47:15: error[invalid-argument-type] Argument is incorrect: Expected `int`, found `Literal[""]`
+namedtuples_define_class.py:48:18: error[invalid-argument-type] Argument is incorrect: Expected `str`, found `Literal[3]`
+namedtuples_define_class.py:49:22: error[too-many-positional-arguments] Too many positional arguments: expected 4, got 5
+namedtuples_define_class.py:50:23: error[unknown-argument] Argument `other` does not match any known parameter
+namedtuples_define_class.py:70:20: error[too-many-positional-arguments] Too many positional arguments: expected 3, got 4
+namedtuples_define_class.py:77:5: error[invalid-named-tuple] NamedTuple field `_y` cannot start with an underscore
+namedtuples_define_class.py:87:5: error[invalid-named-tuple] NamedTuple field without default value cannot follow field(s) with default value(s): Field `latitude` defined here without a default value
+namedtuples_define_class.py:107:5: error[invalid-named-tuple-override] Cannot override NamedTuple field `x` inherited from `Point`
+namedtuples_define_class.py:121:24: error[too-many-positional-arguments] Too many positional arguments: expected 3, got 4
+namedtuples_define_class.py:140:19: error[invalid-argument-type] Argument is incorrect: Expected `str`, found `float`
+namedtuples_define_class.py:147:24: error[invalid-named-tuple] NamedTuple class `Unit` cannot use multiple inheritance except with `Generic[]`
 """
diff --git a/conformance/results/ty/typeddicts_class_syntax.toml b/conformance/results/ty/typeddicts_class_syntax.toml
index 691787e7..ccf44582 100644
--- a/conformance/results/ty/typeddicts_class_syntax.toml
+++ b/conformance/results/ty/typeddicts_class_syntax.toml
@@ -1,10 +1,14 @@
+conformant = "Pass"
+notes = """
+"""
 conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-typeddicts_class_syntax.py:29:5: error[invalid-typed-dict-statement] TypedDict class cannot have methods
-typeddicts_class_syntax.py:33:5: error[invalid-typed-dict-statement] TypedDict class cannot have methods
-typeddicts_class_syntax.py:38:5: error[invalid-typed-dict-statement] TypedDict class cannot have methods
-typeddicts_class_syntax.py:44:32: error[invalid-typed-dict-header] Custom metaclasses are not supported in `TypedDict` definitions
-typeddicts_class_syntax.py:49:32: error[unknown-argument] Unknown keyword argument `other` in `TypedDict` definition
+typeddicts_class_syntax.py:30:5: error[invalid-typed-dict-statement] TypedDict class cannot have methods
+typeddicts_class_syntax.py:34:5: error[invalid-typed-dict-statement] TypedDict class cannot have methods
+typeddicts_class_syntax.py:39:5: error[invalid-typed-dict-statement] TypedDict class cannot have methods
+typeddicts_class_syntax.py:45:32: error[invalid-typed-dict-header] Custom metaclasses are not supported in `TypedDict` definitions
+typeddicts_class_syntax.py:50:32: error[unknown-argument] Unknown keyword argument `other` in `TypedDict` definition
+typeddicts_class_syntax.py:65:28: error[invalid-key] Unknown key "z" for TypedDict `ConditionalField`
 """
diff --git a/conformance/results/zuban/dataclasses_usage.toml b/conformance/results/zuban/dataclasses_usage.toml
index 197dc171..8e2a7ccc 100644
--- a/conformance/results/zuban/dataclasses_usage.toml
+++ b/conformance/results/zuban/dataclasses_usage.toml
@@ -2,15 +2,16 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-dataclasses_usage.py:50: error: Missing positional argument "unit_price" in call to "InventoryItem"  [call-arg]
-dataclasses_usage.py:51: error: Argument 2 to "InventoryItem" has incompatible type "str"; expected "float"  [arg-type]
-dataclasses_usage.py:52: error: Too many arguments for "InventoryItem"  [call-arg]
-dataclasses_usage.py:61: error: Attributes without a default cannot follow attributes with one  [misc]
-dataclasses_usage.py:67: error: Attributes without a default cannot follow attributes with one  [misc]
-dataclasses_usage.py:73: error: Attributes without a default cannot follow attributes with one  [misc]
-dataclasses_usage.py:83: error: Too many arguments for "DC4"  [call-arg]
-dataclasses_usage.py:88: error: Argument "default_factory" to "field" has incompatible type "type[str]"; expected "Callable[[], int]"  [arg-type]
-dataclasses_usage.py:127: error: Too many arguments for "DC7"  [call-arg]
-dataclasses_usage.py:130: error: Missing positional argument "y" in call to "DC8"  [call-arg]
-dataclasses_usage.py:179: error: Too many arguments for "DC13"  [call-arg]
+dataclasses_usage.py:51: error: Missing positional argument "unit_price" in call to "InventoryItem"  [call-arg]
+dataclasses_usage.py:52: error: Argument 2 to "InventoryItem" has incompatible type "str"; expected "float"  [arg-type]
+dataclasses_usage.py:53: error: Too many arguments for "InventoryItem"  [call-arg]
+dataclasses_usage.py:62: error: Attributes without a default cannot follow attributes with one  [misc]
+dataclasses_usage.py:68: error: Attributes without a default cannot follow attributes with one  [misc]
+dataclasses_usage.py:74: error: Attributes without a default cannot follow attributes with one  [misc]
+dataclasses_usage.py:84: error: Too many arguments for "DC4"  [call-arg]
+dataclasses_usage.py:89: error: Argument "default_factory" to "field" has incompatible type "type[str]"; expected "Callable[[], int]"  [arg-type]
+dataclasses_usage.py:128: error: Too many arguments for "DC7"  [call-arg]
+dataclasses_usage.py:131: error: Missing positional argument "y" in call to "DC8"  [call-arg]
+dataclasses_usage.py:180: error: Too many arguments for "DC13"  [call-arg]
+dataclasses_usage.py:246: error: Too many arguments for "DC19"  [call-arg]
 """
diff --git a/conformance/results/zuban/enums_definition.toml b/conformance/results/zuban/enums_definition.toml
index a98bcdae..300aa75a 100644
--- a/conformance/results/zuban/enums_definition.toml
+++ b/conformance/results/zuban/enums_definition.toml
@@ -2,5 +2,6 @@ conformance_automated = "Pass"
 errors_diff = """
 """
 output = """
-enums_definition.py:24: error: Too many arguments for Enum()  [call-arg]
+enums_definition.py:25: error: Too many arguments for Enum()  [call-arg]
+enums_definition.py:92: error: "type[Color12]" has no attribute "BLUE"  [attr-defined]
 """
diff --git a/conformance/results/zuban/namedtuples_define_class.toml b/conformance/results/zuban/namedtuples_define_class.toml
index e2e3edeb..abad1ec5 100644
--- a/conformance/results/zuban/namedtuples_define_class.toml
+++ b/conformance/results/zuban/namedtuples_define_class.toml
@@ -1,21 +1,30 @@
+conformant = "Partial"
 notes = """
+Does not support version-conditional fields in NamedTuple definitions.
 """
-conformance_automated = "Pass"
+conformance_automated = "Fail"
 errors_diff = """
+Line 114: Unexpected errors ['namedtuples_define_class.py:114: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]']
+Line 116: Unexpected errors ['namedtuples_define_class.py:116: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]']
+Line 120: Unexpected errors ['namedtuples_define_class.py:120: error: Too many arguments for "ConditionalField"  [call-arg]']
 """
 output = """
-namedtuples_define_class.py:32: error: Tuple index out of range  [misc]
 namedtuples_define_class.py:33: error: Tuple index out of range  [misc]
-namedtuples_define_class.py:44: error: Missing positional argument "y" in call to "Point"  [call-arg]
+namedtuples_define_class.py:34: error: Tuple index out of range  [misc]
 namedtuples_define_class.py:45: error: Missing positional argument "y" in call to "Point"  [call-arg]
-namedtuples_define_class.py:46: error: Argument 2 to "Point" has incompatible type "str"; expected "int"  [arg-type]
-namedtuples_define_class.py:47: error: Argument "units" to "Point" has incompatible type "int"; expected "str"  [arg-type]
-namedtuples_define_class.py:48: error: Too many arguments for "Point"  [call-arg]
-namedtuples_define_class.py:49: error: Unexpected keyword argument "other" for "Point"  [call-arg]
-namedtuples_define_class.py:69: error: Too many arguments for "Point2"  [call-arg]
-namedtuples_define_class.py:76: error: NamedTuple field name cannot start with an underscore: _y  [misc]
-namedtuples_define_class.py:86: error: Non-default NamedTuple fields cannot follow default fields  [misc]
-namedtuples_define_class.py:106: error: NamedTuple attributes cannot be overridden in subclasses  [misc]
-namedtuples_define_class.py:125: error: Argument 2 to "Property" has incompatible type "float"; expected "str"  [arg-type]
-namedtuples_define_class.py:132: error: NamedTuple should be a single base  [misc]
+namedtuples_define_class.py:46: error: Missing positional argument "y" in call to "Point"  [call-arg]
+namedtuples_define_class.py:47: error: Argument 2 to "Point" has incompatible type "str"; expected "int"  [arg-type]
+namedtuples_define_class.py:48: error: Argument "units" to "Point" has incompatible type "int"; expected "str"  [arg-type]
+namedtuples_define_class.py:49: error: Too many arguments for "Point"  [call-arg]
+namedtuples_define_class.py:50: error: Unexpected keyword argument "other" for "Point"  [call-arg]
+namedtuples_define_class.py:70: error: Too many arguments for "Point2"  [call-arg]
+namedtuples_define_class.py:77: error: NamedTuple field name cannot start with an underscore: _y  [misc]
+namedtuples_define_class.py:87: error: Non-default NamedTuple fields cannot follow default fields  [misc]
+namedtuples_define_class.py:107: error: NamedTuple attributes cannot be overridden in subclasses  [misc]
+namedtuples_define_class.py:114: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]
+namedtuples_define_class.py:116: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"  [misc]
+namedtuples_define_class.py:120: error: Too many arguments for "ConditionalField"  [call-arg]
+namedtuples_define_class.py:121: error: Too many arguments for "ConditionalField"  [call-arg]
+namedtuples_define_class.py:140: error: Argument 2 to "Property" has incompatible type "float"; expected "str"  [arg-type]
+namedtuples_define_class.py:147: error: NamedTuple should be a single base  [misc]
 """
diff --git a/conformance/results/zuban/typeddicts_class_syntax.toml b/conformance/results/zuban/typeddicts_class_syntax.toml
index 68741c76..cf2dfe8c 100644
--- a/conformance/results/zuban/typeddicts_class_syntax.toml
+++ b/conformance/results/zuban/typeddicts_class_syntax.toml
@@ -1,10 +1,21 @@
-conformance_automated = "Pass"
+conformant = "Partial"
+notes = """
+Does not support version-conditional items in TypedDict definitions.
+"""
+conformance_automated = "Fail"
 errors_diff = """
+Line 58: Unexpected errors ['typeddicts_class_syntax.py:58: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]']
+Line 60: Unexpected errors ['typeddicts_class_syntax.py:60: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]']
+Line 64: Unexpected errors ['typeddicts_class_syntax.py:64: error: Extra key "y" for TypedDict "ConditionalField"  [typeddict-unknown-key]']
 """
 output = """
-typeddicts_class_syntax.py:29: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
-typeddicts_class_syntax.py:33: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
-typeddicts_class_syntax.py:38: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
-typeddicts_class_syntax.py:44: error: Unexpected keyword argument "metaclass" for "TypedDict"  [call-arg]
-typeddicts_class_syntax.py:49: error: Unexpected keyword argument "other" for "TypedDict"  [call-arg]
+typeddicts_class_syntax.py:30: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:34: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:39: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:45: error: Unexpected keyword argument "metaclass" for "TypedDict"  [call-arg]
+typeddicts_class_syntax.py:50: error: Unexpected keyword argument "other" for "TypedDict"  [call-arg]
+typeddicts_class_syntax.py:58: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:60: error: Invalid statement in TypedDict definition; expected "field_name: field_type"  [misc]
+typeddicts_class_syntax.py:64: error: Extra key "y" for TypedDict "ConditionalField"  [typeddict-unknown-key]
+typeddicts_class_syntax.py:65: error: Extra keys ("y", "z") for TypedDict "ConditionalField"  [typeddict-unknown-key]
 """
diff --git a/conformance/tests/dataclasses_usage.py b/conformance/tests/dataclasses_usage.py
index d26eaeb5..6e9c0e6b 100644
--- a/conformance/tests/dataclasses_usage.py
+++ b/conformance/tests/dataclasses_usage.py
@@ -7,6 +7,7 @@
 
 from dataclasses import InitVar, dataclass, field
 from typing import Any, Callable, ClassVar, Generic, Protocol, TypeVar, assert_type
+import sys
 
 T = TypeVar("T")
 
@@ -226,3 +227,20 @@ class DC18:
     # This may generate a type checker error because an unannotated field
     # will result in a runtime exception.
     y = field()  # E?
+
+
+# > Dataclass fields may be conditional, via checks of the same
+# > statically-known conditions that a type-checker understands elsewhere,
+# > such as Python version:
+
+@dataclass
+class DC19:
+    x: int
+    if sys.version_info >= (3, 12):
+        y: int
+    if sys.version_info >= (4, 0):
+        z: int
+
+# The conformance suite runs type checkers configured to Python 3.12 or later:
+DC19(1, 2)
+DC19(1, 2, 3)  # E
diff --git a/conformance/tests/enums_definition.py b/conformance/tests/enums_definition.py
index 31a137c4..480a0651 100644
--- a/conformance/tests/enums_definition.py
+++ b/conformance/tests/enums_definition.py
@@ -6,6 +6,7 @@
 
 from enum import Enum, EnumType
 from typing import Literal, assert_type
+import sys
 
 # > Type checkers should support the class syntax
 
@@ -73,3 +74,20 @@ class Color11(CustomEnum2):
 
 
 assert_type(Color11.RED, Literal[Color11.RED])
+
+# > Enum members may be conditional, via checks of the same
+# > statically-known conditions that a type-checker understands elsewhere,
+# > such as Python version:
+
+class Color12(Enum):
+    RED = 1
+    if sys.version_info >= (3, 12):
+        GREEN = 2
+    if sys.version_info >= (4, 0):
+        BLUE = 3
+
+# The conformance suite runs type checkers configured to Python 3.12 or later:
+assert_type(Color12.RED, Literal[Color12.RED])
+assert_type(Color12.GREEN, Literal[Color12.GREEN])
+Color12.BLUE  # E
+
diff --git a/conformance/tests/namedtuples_define_class.py b/conformance/tests/namedtuples_define_class.py
index 5e6e9c4c..03a631bf 100644
--- a/conformance/tests/namedtuples_define_class.py
+++ b/conformance/tests/namedtuples_define_class.py
@@ -7,6 +7,7 @@
 # > Type checkers should support the class syntax
 
 from typing import Generic, NamedTuple, TypeVar, assert_type
+import sys
 
 
 class Point(NamedTuple):
@@ -105,6 +106,20 @@ class BadPointWithName(Point):
     name: str = ""  # OK
     x: int = 0  # E
 
+# > Namedtuple fields may be conditional, via checks of the same statically-known
+# > conditions that a type-checker understands elsewhere, such as Python version::
+
+class ConditionalField(NamedTuple):
+    x: int
+    if sys.version_info >= (3, 12):
+        y: int
+    if sys.version_info >= (4, 0):
+        z: int
+
+# The conformance suite runs type checkers configured to Python 3.12 or later:
+ConditionalField(1, 2)
+ConditionalField(1, 2, 3)  # E
+
 
 # > In Python 3.11 and newer, the class syntax supports generic named tuple classes.
 # > Type checkers should support this.
diff --git a/conformance/tests/typeddicts_class_syntax.py b/conformance/tests/typeddicts_class_syntax.py
index b83f50bf..923bf155 100644
--- a/conformance/tests/typeddicts_class_syntax.py
+++ b/conformance/tests/typeddicts_class_syntax.py
@@ -5,6 +5,7 @@
 # Specification: https://typing.readthedocs.io/en/latest/spec/typeddict.html#typeddict
 
 from typing import Generic, TypeVar, TypedDict
+import sys
 
 
 class Movie(TypedDict):
@@ -49,6 +50,20 @@ class BadTypedDict2(TypedDict, metaclass=type):  # E
 class BadTypedDict3(TypedDict, other=True):  # E
     name: str
 
+# > `if` conditions that the type checker is able to
+# > statically evaluate are also permitted (e.g. `if sys.version_info > (3, 14)`),
+# > in order to specify items that exist only under the given conditions.
+class ConditionalField(TypedDict):
+    x: int
+    if sys.version_info >= (3, 12):
+        y: int
+    if sys.version_info >= (4, 0):
+        z: int
+
+# The conformance suite runs type checkers configured to Python 3.12 or later:
+ConditionalField(x=1, y=2)
+ConditionalField(x=1, y=2, z=3)  # E
+
 
 # > TypedDicts may be made generic by adding Generic[T] among the bases.
 T = TypeVar("T")
diff --git a/docs/spec/dataclasses.rst b/docs/spec/dataclasses.rst
index 77a77574..ef08344b 100644
--- a/docs/spec/dataclasses.rst
+++ b/docs/spec/dataclasses.rst
@@ -122,6 +122,19 @@ Metaclass example
       id: int
       name: str
 
+Conditional fields
+""""""""""""""""""
+
+Dataclass fields may be conditional, via checks of the same
+:ref:`statically-known conditions<version-and-platform-checks>`
+that a type-checker understands elsewhere, such as Python version::
+
+    @dataclass
+    class Person:
+        name: str
+        if sys.version_info >= (3, 14):
+            age: int
+
 Decorator function and class/metaclass parameters
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/docs/spec/enums.rst b/docs/spec/enums.rst
index b90e5dbd..ecb283d5 100644
--- a/docs/spec/enums.rst
+++ b/docs/spec/enums.rst
@@ -59,6 +59,15 @@ checkers should treat such classes as enums::
         GREEN = 2
         BLUE = 3
 
+Enum members may be conditional, via checks of the same
+:ref:`statically-known conditions<version-and-platform-checks>`
+that a type-checker understands elsewhere, such as Python version::
+
+    class Color(Enum):
+        RED = 1
+        if sys.version_info >= (3, 14):
+            BLUE = 2
+
 
 Enum Behaviors
 --------------
diff --git a/docs/spec/namedtuples.rst b/docs/spec/namedtuples.rst
index 5ccf9d5b..87a6e433 100644
--- a/docs/spec/namedtuples.rst
+++ b/docs/spec/namedtuples.rst
@@ -54,6 +54,15 @@ in the base class::
         name: str  # OK
         x: int  # Type error (invalid override of named tuple field)
 
+Namedtuple fields may be conditional, via checks of the same
+:ref:`statically-known conditions<version-and-platform-checks>`
+that a type-checker understands elsewhere, such as Python version::
+
+    class ConditionalField(NamedTuple):
+        x: int
+        if sys.version_info >= (3, 14):
+            y: str
+
 In Python 3.11 and newer, the class syntax supports generic named tuple classes.
 Type checkers should support this::
 
diff --git a/docs/spec/typeddict.rst b/docs/spec/typeddict.rst
index 81b72ea9..cff7e849 100644
--- a/docs/spec/typeddict.rst
+++ b/docs/spec/typeddict.rst
@@ -122,10 +122,15 @@ in the class definition:
   :term:`read-only`. Other type qualifiers are not allowed. If the extra items type
   is ``Never``, no extra items are allowed, so this is equivalent to ``closed=True``.
 
-The body of the class definition defines the :term:`items <item>` of the TypedDict type.
-It may also contain a docstring or ``pass`` statements (primarily to allow the creation of
-an empty TypedDict). No other statements are allowed, and type checkers should report an
-error if any are present. Type comments are not supported for creating TypedDict items.
+The body of the class definition defines the :term:`items <item>` of the
+TypedDict type. It may also contain a docstring or ``pass`` statements
+(primarily to allow the creation of an empty TypedDict). `if` conditions that
+the type checker is able to
+:ref:`statically evaluate<version-and-platform-checks>` are also permitted (e.g.
+`if sys.version_info > (3, 14)`), in order to specify items that exist only under
+the given conditions. No other statements are allowed, and type checkers should
+report an error if any are present. Type comments are not supported for
+creating TypedDict items.
 
 .. _`required-notrequired`:
 .. _`required`: