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Allow errors for unsound Self definitions on non-final classes #2221

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Allow errors for unsound Self definitions on non-final classes #2221

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82ad890
Allow errors for unsound Self definitions on non-final classes
davidhalter Mar 16, 2026
0b6a395
Merge remote-tracking branch 'origin/main' into allow-unsound-error-s…
davidhalter Mar 30, 2026
41d15d5
Update zuban and run results
davidhalter Mar 30, 2026
cd0cee6
Upgrade zuban in uv lock
davidhalter Mar 30, 2026
ae0d7a1
Rerun mypy conformance tests
davidhalter Mar 30, 2026
ac4622f
Allow type checkers to generate an error when list[Self] instance var…
davidhalter Mar 30, 2026
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12 changes: 6 additions & 6 deletions conformance/results/mypy/generics_self_advanced.toml
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Expand Up @@ -7,14 +7,14 @@ Does not retain `Self` when accessing attribute through `type[Self]`.
"""
output = """
generics_self_advanced.py:35: error: Expression is of type "ChildB", not "Self" [assert-type]
generics_self_advanced.py:38: error: Expression is of type "ChildB", not "Self" [assert-type]
generics_self_advanced.py:42: error: Expression is of type "type[ChildB]", not "type[Self]" [assert-type]
generics_self_advanced.py:45: error: Expression is of type "ChildB", not "Self" [assert-type]
generics_self_advanced.py:41: error: Expression is of type "ChildB", not "Self" [assert-type]
generics_self_advanced.py:45: error: Expression is of type "type[ChildB]", not "type[Self]" [assert-type]
generics_self_advanced.py:51: error: Expression is of type "ChildB", not "Self" [assert-type]
"""
conformance_automated = "Fail"
errors_diff = """
Line 35: Unexpected errors ['generics_self_advanced.py:35: error: Expression is of type "ChildB", not "Self" [assert-type]']
Line 38: Unexpected errors ['generics_self_advanced.py:38: error: Expression is of type "ChildB", not "Self" [assert-type]']
Line 42: Unexpected errors ['generics_self_advanced.py:42: error: Expression is of type "type[ChildB]", not "type[Self]" [assert-type]']
Line 45: Unexpected errors ['generics_self_advanced.py:45: error: Expression is of type "ChildB", not "Self" [assert-type]']
Line 41: Unexpected errors ['generics_self_advanced.py:41: error: Expression is of type "ChildB", not "Self" [assert-type]']
Line 45: Unexpected errors ['generics_self_advanced.py:45: error: Expression is of type "type[ChildB]", not "type[Self]" [assert-type]']
Line 51: Unexpected errors ['generics_self_advanced.py:51: error: Expression is of type "ChildB", not "Self" [assert-type]']
"""
8 changes: 4 additions & 4 deletions conformance/results/results.html
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Expand Up @@ -176,7 +176,7 @@ <h3>Python Type System Conformance Test Results</h3>
</th>
<th class='tc-header'><div class='tc-name'>pyright 1.1.408</div>
</th>
<th class='tc-header'><div class='tc-name'>zuban 0.6.1</div>
<th class='tc-header'><div class='tc-name'>zuban 0.6.2</div>
</th>
<th class='tc-header'><div class='tc-name'>pyrefly 0.56.0</div>
</th>
Expand Down Expand Up @@ -227,7 +227,7 @@ <h3>Python Type System Conformance Test Results</h3>
<tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;typeforms_typeform</th>
<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not support assigning Union and GenericAlias objects to their runtime types.</p></span></div></th>
<th class="column col2 not-conformant">Unsupported</th>
<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>TypeForm[Any] is not considered equivalent to itself.</p></span></div></th>
<th class="column col2 conformant">Pass</th>
<th class="column col2 not-conformant">Unsupported</th>
<th class="column col2 not-conformant">Unsupported</th>
</tr>
Expand Down Expand Up @@ -345,7 +345,7 @@ <h3>Python Type System Conformance Test Results</h3>
<tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;generics_self_advanced</th>
<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not infer the type of an unannotated `self` parameter to be type `Self`.</p><p>Does not retain `Self` when calling method that returns `Self`.</p><p>Does not infer the type of an unannotated `cls` parameter to be type `type[Self]`.</p><p>Does not retain `Self` when accessing attribute through `type[Self]`.</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>Doesn't allow accessing `Self` in a classmethod</p></span></div></th>
<th class="column col2 conformant">Pass</th>
<th class="column col2 conformant"><div class="hover-text">Pass*<span class="tooltip-text" id="bottom"><p>Treats attributes not initialized on the class as instance-only</p></span></div></th>
<th class="column col2 conformant">Pass</th>
</tr>
Expand Down Expand Up @@ -837,7 +837,7 @@ <h3>Python Type System Conformance Test Results</h3>
<tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;dataclasses_hash</th>
<th class="column col2 not-conformant"><div class="hover-text">Unsupported<span class="tooltip-text" id="bottom"><p>Does not synthesize `__hash__ = None` as a class attribute for unhashable dataclasses.</p><p>Does not report when an unhashable dataclass has `__hash__` called directly on an instance.</p><p>Does not report when dataclass is not compatible with Hashable protocol.</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 synthesize a `__hash__ = None` class attribute for unhashable dataclasses.</p></span></div></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>Understands the `Hashable` protocol as equivalent to `object`.</p></span></div></th>
</tr>
Expand Down
18 changes: 7 additions & 11 deletions conformance/results/zuban/dataclasses_hash.toml
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@@ -1,17 +1,13 @@
conformance_automated = "Fail"
conformant = "Partial"
notes = """
Does not synthesize a `__hash__ = None` class attribute for unhashable dataclasses.
"""
conformance_automated = "Pass"
errors_diff = """
Line 14: Unexpected errors ['dataclasses_hash.py:14: error: Expression is of type "Callable[[object], int]", not "None" [misc]']
Line 36: Unexpected errors ['dataclasses_hash.py:36: error: Expression is of type "Callable[[object], int]", not "None" [misc]']
"""
output = """
dataclasses_hash.py:14: error: Expression is of type "Callable[[object], int]", not "None" [misc]
dataclasses_hash.py:17: error: "DC1" has no attribute "__hash__" [attr-defined]
dataclasses_hash.py:17: error: "None" not callable [operator]
dataclasses_hash.py:18: error: Incompatible types in assignment (expression has type "DC1", variable has type "Hashable") [assignment]
dataclasses_hash.py:36: error: Expression is of type "Callable[[object], int]", not "None" [misc]
dataclasses_hash.py:39: error: "DC3" has no attribute "__hash__" [attr-defined]
dataclasses_hash.py:18: note: Following member(s) of "DC1" have conflicts:
dataclasses_hash.py:18: note: __hash__: expected "Callable[[], int]", got "None"
dataclasses_hash.py:39: error: "None" not callable [operator]
dataclasses_hash.py:40: error: Incompatible types in assignment (expression has type "DC3", variable has type "Hashable") [assignment]
dataclasses_hash.py:40: note: Following member(s) of "DC3" have conflicts:
dataclasses_hash.py:40: note: __hash__: expected "Callable[[], int]", got "None"
"""
11 changes: 2 additions & 9 deletions conformance/results/zuban/generics_self_advanced.toml
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@@ -1,13 +1,6 @@
conformant = "Partial"
notes = """
Doesn't allow accessing `Self` in a classmethod
"""
conformance_automated = "Fail"
conformance_automated = "Pass"
errors_diff = """
Line 43: Unexpected errors ['generics_self_advanced.py:43: error: Access to generic instance variables via class is ambiguous [misc]']
Line 44: Unexpected errors ['generics_self_advanced.py:44: error: Access to generic instance variables via class is ambiguous [misc]']
"""
output = """
generics_self_advanced.py:43: error: Access to generic instance variables via class is ambiguous [misc]
generics_self_advanced.py:44: error: Access to generic instance variables via class is ambiguous [misc]
generics_self_advanced.py:48: error: Access to generic instance variables via class is ambiguous [misc]
"""
8 changes: 1 addition & 7 deletions conformance/results/zuban/typeforms_typeform.toml
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@@ -1,15 +1,9 @@
conformant = "Partial"
notes = """
TypeForm[Any] is not considered equivalent to itself.
"""
conformance_automated = "Fail"
conformance_automated = "Pass"
errors_diff = """
Line 41: Unexpected errors ['typeforms_typeform.py:41: error: Expression is of type "typing.TypeForm(Any)", not "typing.TypeForm(Any)" [misc]']
"""
output = """
typeforms_typeform.py:23: error: Incompatible types in assignment (expression has type "typing.TypeForm(str | int)", variable has type "typing.TypeForm(str | None)") [assignment]
typeforms_typeform.py:24: error: Incompatible types in assignment (expression has type "type[list[str | None]]", variable has type "typing.TypeForm(str | None)") [assignment]
typeforms_typeform.py:41: error: Expression is of type "typing.TypeForm(Any)", not "typing.TypeForm(Any)" [misc]
typeforms_typeform.py:59: error: Invalid syntax [syntax]
typeforms_typeform.py:67: error: Invalid type comment or annotation [valid-type]
typeforms_typeform.py:68: error: Syntax error in type annotation [valid-type]
Expand Down
2 changes: 1 addition & 1 deletion conformance/results/zuban/version.toml
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@@ -1 +1 @@
version = "zuban 0.6.1"
version = "zuban 0.6.2"
14 changes: 10 additions & 4 deletions conformance/tests/generics_self_advanced.py
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Expand Up @@ -33,13 +33,19 @@ class ChildB(ParentB):

def method2(self) -> None:
assert_type(self, Self)
assert_type(self.a, list[Self])
assert_type(self.a[0], Self)
# Allow type checkers to error here, since Self definitions on
# non-final classes are unsound.
a = self.a # E?
assert_type(a, list[Self])
assert_type(a[0], Self)
assert_type(self.method1(), Self)

@classmethod
def method3(cls) -> None:
assert_type(cls, type[Self])
assert_type(cls.a, list[Self])
assert_type(cls.a[0], Self)
# Allow type checkers to error here, since Self definitions on
# non-final classes are unsound.
a = cls.a # E?
assert_type(a, list[Self])
assert_type(a[0], Self)
assert_type(cls.method1(), Self)
26 changes: 13 additions & 13 deletions conformance/uv.lock
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