Allow any type to be returned by __new__

[Viicos]

Fixes#8330. Made a first mypy_primer run locally, and had a lot of things breaking, so the fix might be incomplete.

• Fix/add tests in check-classes.test

[intgr]

Please make sure that if the __new__ return is untyped (returns Any) then it uses the class type implicitly. Not sure if that is already covered, but I suspect not.

[Viicos]

Please make sure that if the __new__ return is untyped (returns Any) then it uses the class type implicitly. Not sure if that is already covered, but I suspect not.

Will do. I was excepting to have a mypy_primer output here as it is in typeshed (checks were pending), but I suspect the errors I had are related to this (for example one error was src/pegen/grammar_visualizer.py:60: error: "object" has no attribute "print_grammar_ast", so probably mypy wasn't inferring the class type implicitly)

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

parso (https://github.com/davidhalter/parso)
+ parso/python/pep8.py:38: error: "Type[object]" has no attribute "SUITE" [attr-defined]+ parso/python/pep8.py:124: error: "Type[object]" has no attribute "BACKSLASH" [attr-defined]+ parso/grammar.py:213: error: Incompatible types in assignment (expression has type "object", base class "Grammar" defined the type as "Optional[ErrorFinderConfig]") [assignment]
aioredis (https://github.com/aio-libs/aioredis)
+ aioredis/connection.py:163: error: Dict entry 0 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:164: error: Dict entry 1 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:165: error: Dict entry 2 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:168: error: Dict entry 3 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:171: error: Dict entry 4 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:172: error: Dict entry 5 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:173: error: Dict entry 6 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:174: error: Dict entry 7 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:175: error: Dict entry 8 has incompatible type "str": "Type[BaseException]"; expected "str": "Type[Exception]" [dict-item]+ aioredis/connection.py:177: error: Dict entry 1 has incompatible type "str": "Type[BaseException]"; expected "str": "Union[Type[Exception], Mapping[str, Type[Exception]]]" [dict-item]+ aioredis/connection.py:178: error: Dict entry 2 has incompatible type "str": "Type[BaseException]"; expected "str": "Union[Type[Exception], Mapping[str, Type[Exception]]]" [dict-item]+ aioredis/connection.py:179: error: Dict entry 3 has incompatible type "str": "Type[BaseException]"; expected "str": "Union[Type[Exception], Mapping[str, Type[Exception]]]" [dict-item]+ aioredis/connection.py:180: error: Dict entry 4 has incompatible type "str": "Type[BaseException]"; expected "str": "Union[Type[Exception], Mapping[str, Type[Exception]]]" [dict-item]+ aioredis/connection.py:181: error: Dict entry 5 has incompatible type "str": "Type[BaseException]"; expected "str": "Union[Type[Exception], Mapping[str, Type[Exception]]]" [dict-item]+ aioredis/connection.py:182: error: Dict entry 6 has incompatible type "str": "Type[BaseException]"; expected "str": "Union[Type[Exception], Mapping[str, Type[Exception]]]" [dict-item]+ aioredis/connection.py:207: error: Incompatible return value type (got "BaseException", expected "ResponseError") [return-value]+ aioredis/connection.py:289: error: "BaseException" has no attribute "errno" [attr-defined]+ aioredis/connection.py:420: error: Statement is unreachable [unreachable]+ aioredis/connection.py:461: error: Incompatible types (expression has type "Type[BaseException]", TypedDict item "protocolError" has type "Callable[[str], Exception]") [typeddict-item]+ aioredis/connection.py:517: error: "BaseException" has no attribute "errno" [attr-defined]+ aioredis/connection.py:1393: error: "object" has no attribute "acquire" [attr-defined]+ aioredis/connection.py:1402: error: "object" has no attribute "release" [attr-defined]+ aioredis/client.py:3430: error: Item "Sequence[Union[bytes, str, memoryview]]" of "Union[Sequence[Union[bytes, str, memoryview]], Mapping[bytes, float]]" has no attribute "keys" [union-attr]+ aioredis/client.py:3430: error: Item "Sequence[Union[bytes, str, memoryview]]" of "Union[Sequence[Union[bytes, str, memoryview]], Mapping[str, float]]" has no attribute "keys" [union-attr]+ aioredis/client.py:3430: error: Item "Sequence[Union[bytes, str, memoryview]]" of "Union[Sequence[Union[bytes, str, memoryview]], Mapping[memoryview, float]]" has no attribute "keys" [union-attr]+ aioredis/client.py:3430: error: Item "Sequence[Union[bytes, str, memoryview]]" of "Union[Sequence[Union[bytes, str, memoryview]], Mapping[bytes, float]]" has no attribute "values" [union-attr]+ aioredis/client.py:3430: error: Item "Sequence[Union[bytes, str, memoryview]]" of "Union[Sequence[Union[bytes, str, memoryview]], Mapping[str, float]]" has no attribute "values" [union-attr]+ aioredis/client.py:3430: error: Item "Sequence[Union[bytes, str, memoryview]]" of "Union[Sequence[Union[bytes, str, memoryview]], Mapping[memoryview, float]]" has no attribute "values" [union-attr]+ aioredis/client.py:3533: error: Argument 2 to "warn" has incompatible type "Type[BaseException]"; expected "Optional[Type[Warning]]" [arg-type]+ aioredis/client.py:4525: error: Argument 1 to "annotate_exception" of "Pipeline" has incompatible type "BaseException"; expected "Exception" [arg-type]+ aioredis/client.py:4593: error: Argument 1 to "annotate_exception" of "Pipeline" has incompatible type "BaseException"; expected "Exception" [arg-type]
nionutils (https://github.com/nion-software/nionutils)
+ nion/utils/Promise.py:20: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Promise.py:20: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ReferenceCounting.py:58: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ReferenceCounting.py:58: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ReferenceCounting.py:64: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ReferenceCounting.py:64: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Event.py:82: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Event.py:82: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Event.py:86: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Event.py:86: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Event.py:102: error: "Type[List[Any]]" has no attribute "from_list" [attr-defined]+ nion/utils/Event.py:107: error: "Type[List[Any]]" has no attribute "from_list" [attr-defined]+ nion/utils/Event.py:112: error: "Type[List[Any]]" has no attribute "from_list" [attr-defined]+ nion/utils/Event.py:123: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Event.py:123: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Event.py:140: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Event.py:140: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Event.py:159: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Event.py:159: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Recorder.py:115: error: Argument 1 to "KeyAccessor" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:119: error: Argument 1 to "KeyAccessor" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:129: error: Incompatible return value type (got "object", expected "Accessor") [return-value]+ nion/utils/Recorder.py:140: error: Argument 1 to "KeyRecorderEntry" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:145: error: Argument 1 to "KeyAccessor" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:146: error: Argument 1 to "KeyRecorderEntry" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:154: error: Argument 1 to "KeyAccessor" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:155: error: Argument 1 to "KeyAccessor" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:156: error: Argument 1 to "InsertRecorderEntry" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:161: error: Argument 1 to "KeyAccessor" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/Recorder.py:163: error: Argument 1 to "RemoveRecorderEntry" has incompatible type "object"; expected "Accessor" [arg-type]+ nion/utils/ListModel.py:312: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:312: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:346: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:346: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:360: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:360: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:383: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:383: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:393: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:393: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:423: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:423: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:466: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:466: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:478: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:478: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:544: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:544: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:662: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:662: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:668: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:668: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:679: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:679: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:724: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:724: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:752: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:752: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:812: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:812: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:823: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:823: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:866: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:866: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:910: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:910: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ListModel.py:925: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/ListModel.py:925: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/ThreadPool.py:40: error: Argument 5 to "finalize" has incompatible type "object"; expected "Event" [arg-type]+ nion/utils/ThreadPool.py:61: error: "object" has no attribute "is_set" [attr-defined]+ nion/utils/ThreadPool.py:70: error: "object" has no attribute "is_set" [attr-defined]+ nion/utils/ThreadPool.py:93: error: Argument 1 to "DispatcherInfo" has incompatible type "object"; expected "_RLock" [arg-type]+ nion/utils/ThreadPool.py:93: error: Argument 4 to "DispatcherInfo" has incompatible type "object"; expected "Event" [arg-type]+ nion/utils/Process.py:62: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Process.py:62: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Process.py:66: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Process.py:66: error: "object" has no attribute "__exit__" [attr-defined]+ nion/utils/Process.py:71: error: "object" has no attribute "__enter__" [attr-defined]+ nion/utils/Process.py:71: error: "object" has no attribute "__exit__" [attr-defined]
poetry (https://github.com/python-poetry/poetry)
+ src/poetry/utils/setup_reader.py:126: error: Left operand of "and" is always true [redundant-expr]+ src/poetry/utils/setup_reader.py:130: error: "stmt" has no attribute "test" [attr-defined]+ src/poetry/utils/setup_reader.py:134: error: "AST" has no attribute "left" [attr-defined]+ src/poetry/utils/setup_reader.py:138: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:154: error: "stmt" has no attribute "value" [attr-defined]+ src/poetry/utils/setup_reader.py:158: error: "AST" has no attribute "func" [attr-defined]+ src/poetry/utils/setup_reader.py:159: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:161: error: "AST" has no attribute "value" [attr-defined]+ src/poetry/utils/setup_reader.py:162: error: "AST" has no attribute "attr" [attr-defined]+ src/poetry/utils/setup_reader.py:166: error: Incompatible return value type (got "Tuple[AST, List[stmt]]", expected "Optional[Tuple[Call, List[stmt]]]") [return-value]+ src/poetry/utils/setup_reader.py:178: error: "stmt" has no attribute "body" [attr-defined]+ src/poetry/utils/setup_reader.py:198: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:203: error: "expr" has no attribute "func" [attr-defined]+ src/poetry/utils/setup_reader.py:206: error: "expr" has no attribute "func" [attr-defined]+ src/poetry/utils/setup_reader.py:206: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:209: error: Argument 1 to "_find_in_call" of "SetupReader" has incompatible type "expr"; expected "Call" [arg-type]+ src/poetry/utils/setup_reader.py:217: error: "AST" has no attribute "elts" [attr-defined]+ src/poetry/utils/setup_reader.py:219: error: "AST" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:221: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:224: error: "expr" has no attribute "elts" [attr-defined]+ src/poetry/utils/setup_reader.py:226: error: "AST" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:242: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:247: error: "expr" has no attribute "func" [attr-defined]+ src/poetry/utils/setup_reader.py:250: error: "expr" has no attribute "func" [attr-defined]+ src/poetry/utils/setup_reader.py:250: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:253: error: Argument 1 to "_find_in_call" of "SetupReader" has incompatible type "expr"; expected "Call" [arg-type]+ src/poetry/utils/setup_reader.py:262: error: "AST" has no attribute "keys" [attr-defined]+ src/poetry/utils/setup_reader.py:262: error: "AST" has no attribute "values" [attr-defined]+ src/poetry/utils/setup_reader.py:267: error: "expr" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:270: error: "AST" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:271: error: "AST" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:271: error: "expr" has no attribute "elts" [attr-defined]+ src/poetry/utils/setup_reader.py:274: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:279: error: "expr" has no attribute "keys" [attr-defined]+ src/poetry/utils/setup_reader.py:279: error: "expr" has no attribute "values" [attr-defined]+ src/poetry/utils/setup_reader.py:284: error: "expr" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:287: error: "AST" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:288: error: "AST" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:288: error: "expr" has no attribute "elts" [attr-defined]+ src/poetry/utils/setup_reader.py:304: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:309: error: "expr" has no attribute "func" [attr-defined]+ src/poetry/utils/setup_reader.py:312: error: "expr" has no attribute "func" [attr-defined]+ src/poetry/utils/setup_reader.py:312: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:315: error: Argument 1 to "_find_in_call" of "SetupReader" has incompatible type "expr"; expected "Call" [arg-type]+ src/poetry/utils/setup_reader.py:323: error: Returning Any from function declared to return "Optional[str]" [no-any-return]+ src/poetry/utils/setup_reader.py:323: error: "AST" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:325: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:328: error: Returning Any from function declared to return "Optional[str]" [no-any-return]+ src/poetry/utils/setup_reader.py:328: error: "expr" has no attribute "s" [attr-defined]+ src/poetry/utils/setup_reader.py:353: error: "stmt" has no attribute "targets" [attr-defined]+ src/poetry/utils/setup_reader.py:357: error: "AST" has no attribute "id" [attr-defined]+ src/poetry/utils/setup_reader.py:358: error: Returning Any from function declared to return "Optional[expr]" [no-any-return]+ src/poetry/utils/setup_reader.py:358: error: "stmt" has no attribute "value" [attr-defined]+ src/poetry/utils/setup_reader.py:364: error: "expr" has no attribute "s" [attr-defined]+ src/poetry/mixology/term.py:48: error: Returning Any from function declared to return "bool" [no-any-return]+ src/poetry/mixology/term.py:50: error: "Type[object]" has no attribute "SUBSET" [attr-defined]+ src/poetry/mixology/term.py:66: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:66: error: "Type[object]" has no attribute "DISJOINT" [attr-defined]+ src/poetry/mixology/term.py:70: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:70: error: "Type[object]" has no attribute "SUBSET" [attr-defined]+ src/poetry/mixology/term.py:74: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:74: error: "Type[object]" has no attribute "DISJOINT" [attr-defined]+ src/poetry/mixology/term.py:76: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:76: error: "Type[object]" has no attribute "OVERLAPPING" [attr-defined]+ src/poetry/mixology/term.py:79: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:79: error: "Type[object]" has no attribute "OVERLAPPING" [attr-defined]+ src/poetry/mixology/term.py:83: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:83: error: "Type[object]" has no attribute "DISJOINT" [attr-defined]+ src/poetry/mixology/term.py:87: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:87: error: "Type[object]" has no attribute "OVERLAPPING" [attr-defined]+ src/poetry/mixology/term.py:91: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:91: error: "Type[object]" has no attribute "SUBSET" [attr-defined]+ src/poetry/mixology/term.py:95: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:95: error: "Type[object]" has no attribute "SUBSET" [attr-defined]+ src/poetry/mixology/term.py:99: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:99: error: "Type[object]" has no attribute "DISJOINT" [attr-defined]+ src/poetry/mixology/term.py:102: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:102: error: "Type[object]" has no attribute "OVERLAPPING" [attr-defined]+ src/poetry/mixology/term.py:105: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:105: error: "Type[object]" has no attribute "OVERLAPPING" [attr-defined]+ src/poetry/mixology/term.py:109: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:109: error: "Type[object]" has no attribute "SUBSET" [attr-defined]+ src/poetry/mixology/term.py:113: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/term.py:113: error: "Type[object]" has no attribute "OVERLAPPING" [attr-defined]+ src/poetry/repositories/repository_pool.py:43: error: Incompatible types in assignment (expression has type "Dict[_KT, _VT]", variable has type "OrderedDict[str, PrioritizedRepository]") [assignment]+ src/poetry/mixology/incompatibility.py:267: error: Left operand of "and" is always true [redundant-expr]+ src/poetry/repositories/pool.py:26: error: Argument 2 to "warn" has incompatible type "Type[BaseException]"; expected "Optional[Type[Warning]]" [arg-type]+ src/poetry/console/logging/io_formatter.py:29: error: "object" has no attribute "format" [attr-defined]+ src/poetry/mixology/partial_solution.py:204: error: Returning Any from function declared to return "bool" [no-any-return]+ src/poetry/mixology/partial_solution.py:204: error: "Type[object]" has no attribute "SUBSET" [attr-defined]+ src/poetry/mixology/partial_solution.py:213: error: Returning Any from function declared to return "str" [no-any-return]+ src/poetry/mixology/partial_solution.py:213: error: "Type[object]" has no attribute "OVERLAPPING" [attr-defined]+ src/poetry/mixology/version_solver.py:105: error: Argument 2 to "Incompatibility" has incompatible type "BaseException"; expected "IncompatibilityCause" [arg-type]+ src/poetry/mixology/version_solver.py:182: error: "Type[object]" has no attribute "DISJOINT" [attr-defined]
... (truncated 50 lines) ...
pandas (https://github.com/pandas-dev/pandas)
+ pandas/io/sas/sas_constants.py:184: error: "Type[object]" has no attribute "row_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:185: error: "Type[object]" has no attribute "row_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:186: error: "Type[object]" has no attribute "row_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:187: error: "Type[object]" has no attribute "row_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:188: error: "Type[object]" has no attribute "column_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:189: error: "Type[object]" has no attribute "column_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:190: error: "Type[object]" has no attribute "column_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:191: error: "Type[object]" has no attribute "column_size_index" [attr-defined]+ pandas/io/sas/sas_constants.py:192: error: "Type[object]" has no attribute "subheader_counts_index" [attr-defined]+ pandas/io/sas/sas_constants.py:193: error: "Type[object]" has no attribute "subheader_counts_index" [attr-defined]+ pandas/io/sas/sas_constants.py:194: error: "Type[object]" has no attribute "subheader_counts_index" [attr-defined]+ pandas/io/sas/sas_constants.py:195: error: "Type[object]" has no attribute "subheader_counts_index" [attr-defined]+ pandas/io/sas/sas_constants.py:196: error: "Type[object]" has no attribute "column_text_index" [attr-defined]+ pandas/io/sas/sas_constants.py:197: error: "Type[object]" has no attribute "column_text_index" [attr-defined]+ pandas/io/sas/sas_constants.py:198: error: "Type[object]" has no attribute "column_text_index" [attr-defined]+ pandas/io/sas/sas_constants.py:199: error: "Type[object]" has no attribute "column_text_index" [attr-defined]+ pandas/io/sas/sas_constants.py:200: error: "Type[object]" has no attribute "column_name_index" [attr-defined]+ pandas/io/sas/sas_constants.py:201: error: "Type[object]" has no attribute "column_name_index" [attr-defined]+ pandas/io/sas/sas_constants.py:202: error: "Type[object]" has no attribute "column_attributes_index" [attr-defined]+ pandas/io/sas/sas_constants.py:203: error: "Type[object]" has no attribute "column_attributes_index" [attr-defined]+ pandas/io/sas/sas_constants.py:204: error: "Type[object]" has no attribute "column_attributes_index" [attr-defined]+ pandas/io/sas/sas_constants.py:205: error: "Type[object]" has no attribute "column_attributes_index" [attr-defined]+ pandas/io/sas/sas_constants.py:206: error: "Type[object]" has no attribute "format_and_label_index" [attr-defined]+ pandas/io/sas/sas_constants.py:207: error: "Type[object]" has no attribute "format_and_label_index" [attr-defined]+ pandas/io/sas/sas_constants.py:208: error: "Type[object]" has no attribute "format_and_label_index" [attr-defined]+ pandas/io/sas/sas_constants.py:209: error: "Type[object]" has no attribute "format_and_label_index" [attr-defined]+ pandas/io/sas/sas_constants.py:210: error: "Type[object]" has no attribute "column_list_index" [attr-defined]+ pandas/io/sas/sas_constants.py:211: error: "Type[object]" has no attribute "column_list_index" [attr-defined]+ pandas/io/sas/sas_constants.py:212: error: "Type[object]" has no attribute "column_list_index" [attr-defined]+ pandas/io/sas/sas_constants.py:213: error: "Type[object]" has no attribute "column_list_index" [attr-defined]+ pandas/util/version/__init__.py:52: error: Incompatible return value type (got "object", expected "NegativeInfinityType") [return-value]+ pandas/util/version/__init__.py:84: error: Incompatible return value type (got "object", expected "InfinityType") [return-value]+ pandas/util/version/__init__.py:160: error: "object" has no attribute "_key" [attr-defined]+ pandas/util/version/__init__.py:178: error: "object" has no attribute "_key" [attr-defined]+ pandas/util/version/__init__.py:189: error: Argument 2 to "warn" has incompatible type "Type[BaseException]"; expected "Optional[Type[Warning]]" [arg-type]+ pandas/util/version/__init__.py:542: error: Incompatible types in assignment (expression has type "object", variable has type "Union[Union[InfinityType, NegativeInfinityType], Tuple[str, int]]") [assignment]+ pandas/util/version/__init__.py:546: error: Incompatible types in assignment (expression has type "object", variable has type "Union[Union[InfinityType, NegativeInfinityType], Tuple[str, int]]") [assignment]+ pandas/util/version/__init__.py:552: error: Incompatible types in assignment (expression has type "object", variable has type "Union[Union[InfinityType, NegativeInfinityType], Tuple[str, int]]") [assignment]+ pandas/util/version/__init__.py:559: error: Incompatible types in assignment (expression has type "object", variable has type "Union[Union[InfinityType, NegativeInfinityType], Tuple[str, int]]") [assignment]+ pandas/util/version/__init__.py:566: error: Incompatible types in assignment (expression has type "object", variable has type "Union[NegativeInfinityType, Tuple[Union[Union[Union[InfinityType, NegativeInfinityType], int, str], Tuple[Union[Union[InfinityType, NegativeInfinityType], int, str], str], Tuple[NegativeInfinityType, Union[Union[InfinityType, NegativeInfinityType], int, str]]], ...]]") [assignment]+ pandas/util/version/__init__.py:576: error: Generator has incompatible item type "Tuple[object, Union[InfinityType, NegativeInfinityType, str]]"; expected "Union[InfinityType, NegativeInfinityType, int, str, Tuple[Union[Union[InfinityType, NegativeInfinityType], int, str], str], Tuple[NegativeInfinityType, Union[Union[InfinityType, NegativeInfinityType], int, str]]]" [misc]+ pandas/_testing/_warnings.py:21: error: Incompatible default for argument "expected_warning" (default has type "Type[BaseException]", argument has type "Union[Type[Warning], bool, Tuple[Type[Warning], ...], None]") [assignment]+ pandas/io/formats/latex.py:471: error: Incompatible return value type (got "RowStringConverter", expected "RowStringIterator") [return-value]+ pandas/io/formats/latex.py:481: error: Incompatible return value type (got "Type[RowStringConverter]", expected "Type[RowStringIterator]") [return-value]+ pandas/io/formats/latex.py:483: error: Incompatible return value type (got "Type[RowStringConverter]", expected "Type[RowStringIterator]") [return-value]+ pandas/compat/__init__.py:154: error: Incompatible return value type (got "Type[lzma.LZMAFile]", expected "Type[pandas.compat.compressors.LZMAFile]") [return-value]+ pandas/util/_decorators.py:57: error: Incompatible types in assignment (expression has type "Type[BaseException]", variable has type "Optional[Type[Warning]]") [assignment]
... (truncated 5382 lines) ...```

[Viicos]

@intgr I'm not familiar with the mypy internal stuff, so I can't really figure out where this implicit class type usage could be implemented. Do you have any ideas about this?

[intgr]

I'm not very familiar either. I wanted to look into it, but haven't found the time yet

[DougLeonard]

Please make sure that if the __new__ return is untyped (returns Any) then it uses the class type implicitly. Not sure if that is already covered, but I suspect not.

I replied here:
#8330 (comment)

[NeilGirdhar]

Please make sure that if the __new__ return is untyped (returns Any) then it uses the class type implicitly. Not sure if that is already covered, but I suspect not.

Just curious, but where does this come up? If that's what's meant, shouldn't these be corrected to return Self?

[intgr]

Please make sure that if the __new__ return is untyped (returns Any) then it uses the class type implicitly. Not sure if that is already covered, but I suspect not.

Just curious, but where does this come up? If that's what's meant, shouldn't these be corrected to return Self?

Yes, that's exactly what I meant.

[DougLeonard]

Please make sure that if the __new__ return is untyped (returns Any) then it uses the class type implicitly. Not sure if that is already covered, but I suspect not.

Just curious, but where does this come up? If that's what's meant, shouldn't these be corrected to return Self?

What should be corrected? The code? Or mypy's assumption about the return type? Sort of saying the same thing maybe, but either way, why should un-annotated valid python code be "rejected" by mypy? The spec seems to me to say it should not. The spec can of course be changed, and actually probably could benefit from a lot of clarification. At some point it's an implementation-defined situation, not a spec-defined one, but then so is all of Perl.

[NeilGirdhar]

What should be corrected? The code? Or mypy's assumption about the return type?

I meant for MyPy not to make assumptions about the return type.

why should un-annotated valid python code be "rejected" by mypy?

If the return type is left as Any, then created objects that have an un-annotated __new__ would have type Any, right? So nothing would be rejected. You would just lose typing information for such objects until __new__ is properly annotated. Seems like a tiny set of cases with an easy fix. I just thought that would be better than creating a special case.

The spec seems to me to say it should not.

Would you mind linking that?

[DougLeonard]

It's in my linked reply above, but not a problem.
From PEP484:

Any function without annotations should be treated as having the most general type possible, or ignored, by any type checker.

Assuming Self is not the most general type possible or allowed by the language.

It seems mypy doesn't presently work like that, but an object instantiation is just a call to a function __new__ and I see nothing in the spec that overrides the above statement for object instantiation, but I well may have missed it. I think it makes sense that a spec compliant type checker should not report type errors in correct code that doesn't have type errors, particularly when the typing philosophy of python is supposed to be "gradual typing," which as I read means first do no harm, and add checking gradually as requested.

Python could probably declare non-subtype return types as UB, but my digging says it doesn't. I'm just here because it was allowed, handling staticness in python isn't obvious to a newcomer, and I did it and I had code that worked. Now I have other code that instantiates a callable that is just as good, drop-in replaceable, and arguably less confusing, maybe, so that's fine too, but it was an unnecessary dead-end that I found through honest, legal, even if smelly (but simpler), means, and it signaled (and enforced) singleton-like intent* automatically for better or worse.

Edit:
*Since there was no instantiation, the __new__, and all direct method calls, accessed the class attributes, not object attributes, so, singleton-like.

[DougLeonard]

If the return type is left as Any, then created objects that have an un-annotated __new__ would have type Any, right? So nothing would be rejected. You would just lose typing information for such objects until __new__ is properly annotated. Seems like a tiny set of cases with an easy fix. I just thought that would be better than creating a special case.

Yes yes. Ok. I thought you said assume "Self"

Just curious, but where does this come up? If that's what's meant, shouldn't these be corrected to return Self?

Maybe if Self is implicitly -> Any then this means the same thing, and I was just confused. It should not mean the Wolf() in Sheep() clothing is assumed as a Sheep(). It should mean it returns the implicit Any return type associated with Sheep.__new__. Maybe that resolves my confusion.

[NeilGirdhar]

Assuming Self is not the most general type possible or allowed by the language.

Totally agree.

Yes yes. Ok. I thought you said assume "Self"

😄 Yeah, sounds like we're actually saying the same thing then!

It should mean it returns the implicit Any return type associated with Sheep.new. Maybe that resolves my confusion.

That's what I'm saying: if __new__ is unannotated, it should be assumed to return Any, and any constructed object has type Any. If the user wants to fix that, they should annotate __new__ correctly.

[studyingegret]

Possible relevant source code locations:

test-data/unit/check-classes.test Lines 7250, 7357
mypy/checker.py Line 1752
mypy/message_registry.py Line 99

(note: as of commit 186515f)