{"record":{"id":"e212d56154072360","repo":"pola-rs/polars","slug":"cannot-compare-self-r-to-value-r","errorCode":null,"errorMessage":"cannot compare {self!r} to {value!r}","messagePattern":"cannot compare (.+?) to (.+?)","errorType":"exception","errorClass":"TypeError","httpStatus":null,"severity":"error","filePath":"py-polars/src/polars/datatype_expr/datatype_expr.py","lineNumber":78,"sourceCode":"    _pydatatype_expr: PyDataTypeExpr = None  # type: ignore[assignment]\n    _accessors: ClassVar[set[str]] = {\n        \"arr\",\n        \"enum\",\n        \"list\",\n        \"struct\",\n    }\n\n    def __eq__(self, value: PolarsDataType | DataTypeExpr) -> pl.Expr:  # type: ignore[override]\n        cmp_with: DataTypeExpr\n        if isinstance(value, pl.DataType):\n            cmp_with = value.to_dtype_expr()\n        elif isinstance(value, pl.DataTypeClass):\n            cmp_with = value.to_dtype_expr()\n        elif isinstance(value, DataTypeExpr):\n            cmp_with = value\n        else:\n            msg = f\"cannot compare {self!r} to {value!r}\"\n            raise TypeError(msg) from None\n\n        return pl.Expr._from_pyexpr(\n            self._pydatatype_expr.equals(cmp_with._pydatatype_expr)\n        )\n\n    def __ne__(self, value: PolarsDataType | DataTypeExpr) -> pl.Expr:  # type: ignore[override]\n        return (self == value).not_()\n\n    @classmethod\n    def _from_pydatatype_expr(cls, pydatatype_expr: PyDataTypeExpr) -> DataTypeExpr:\n        slf = cls()\n        slf._pydatatype_expr = pydatatype_expr\n        return slf\n\n    def inner_dtype(self) -> DataTypeExpr:\n        \"\"\"Get the inner DataType of a List or Array.\"\"\"\n        return DataTypeExpr._from_pydatatype_expr(self._pydatatype_expr.inner_dtype())\n","sourceCodeStart":60,"sourceCodeEnd":96,"githubUrl":"https://github.com/pola-rs/polars/blob/df599052daf96e7a9cc30a3b0c6bd25d6947e3c0/py-polars/src/polars/datatype_expr/datatype_expr.py#L60-L96","documentation":"Error \"cannot compare {self!r} to {value!r}\" thrown in pola-rs/polars.","triggerScenarios":"Thrown at py-polars/src/polars/datatype_expr/datatype_expr.py:78 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"df599052daf96e7a9cc30a3b0c6bd25d6947e3c0","analyzedAt":"2026-08-16T12:10:03.978Z","schemaVersion":2},"datasetVersion":"2026-08-16T13:17:31.715Z"}