intersections become never

[KotlinIsland]

• resolves: intersection type aliases don't work without explicit TypeAlias annotation #518
• resolves: incompatible intersections should become Never #432
• resolves: Intersections with @final types should result in Never #451

[github-actions]

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

jax (https://github.com/google/jax)
- jax/_src/array.py:768:19: error: Intersection of "slice & int" cannot exist: would have incompatible method signatures  [unreachable]
+ jax/_src/api.py:856:16: error: "Never" not callable  [misc]
- jax/_src/api.py:856:16: error: Expression has type "Untyped"  [no-any-expr]
- jax/_src/api.py:856:16: error: Expression has type "Any (from omitted generics)"  [no-any-expr]
- jax/_src/api.py:856:51: error: Call to incomplete function "_std_basis" in typed context  [no-untyped-call]
- jax/_src/api.py:856:51: error: "_std_basis" does not return a value  [func-returns-value]
- jax/_src/api.py:856:51: note: Type is "def (pytree: Untyped) -> None"
- jax/_src/api.py:856:62: error: Cannot determine type of "dyn_args"  [has-type]
- jax/_src/api.py:860:64: error: Expression has type "Any (from omitted generics)"  [no-any-expr]
+ jax/_src/api.py:864:7: error: Statement is unreachable  [unreachable]
- jax/_src/api.py:862:65: error: Expression has type "Any (from omitted generics)"  [no-any-expr]
- jax/_src/api.py:862:68: error: Expression has type "Any (from omitted generics)"  [no-any-expr]
- jax/_src/api.py:864:7: error: Returning Any from function declared to return "None"  [no-any-return]
- jax/_src/api.py:864:14: error: Expression has type "Any"  [no-any-expr]

scikit-learn (https://github.com/scikit-learn/scikit-learn)
- sklearn/model_selection/_search.py:760:39: error: Intersection of "bool & str" cannot exist: would have incompatible method signatures  [unreachable]

sympy (https://github.com/sympy/sympy)
- sympy/matrices/reductions.py:166:16: error: Expression type contains "Any" (has type "bool & FunctionType | (expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/reductions.py:166:16: error: Expression type contains "Any" (has type "(expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/reductions.py:166:28: error: If condition is always false  [redundant-expr]
- sympy/matrices/reductions.py:168:49: error: Expression type contains "Any" (has type "bool & FunctionType | (expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/reductions.py:168:49: error: Expression type contains "Any" (has type "(expr: Untyped) -> None")  [no-any-expr]
- sympy/matrices/reductions.py:214:16: error: Expression type contains "Any" (has type "bool & FunctionType | (expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/reductions.py:214:16: error: Expression type contains "Any" (has type "(expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/reductions.py:214:28: error: If condition is always false  [redundant-expr]
- sympy/matrices/reductions.py:242:49: error: Expression type contains "Any" (has type "bool & FunctionType | (expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/reductions.py:242:49: error: Expression type contains "Any" (has type "(expr: Untyped) -> None")  [no-any-expr]
- sympy/matrices/reductions.py:379:24: error: Incompatible types in assignment (expression has type "(expr: Untyped) -> None", variable has type "bool & FunctionType")  [assignment]
+ sympy/matrices/reductions.py:377:13: error: Statement is unreachable  [unreachable]
+ sympy/matrices/reductions.py:379:24: error: Expression type contains "Any" (has type "(expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/reductions.py:381:57: error: Expression type contains "Any" (has type "(expr: Untyped) -> None")  [no-any-expr]
+ sympy/matrices/eigen.py:206:13: error: Statement is unreachable  [unreachable]
- sympy/matrices/eigen.py:206:13: error: Usage of untyped name "charpoly" in typed context  [no-untyped-usage]
- sympy/matrices/eigen.py:206:24: error: Expression has type "Untyped"  [no-any-expr]
+ sympy/matrices/eigen.py:247:13: error: Statement is unreachable  [unreachable]
- sympy/matrices/eigen.py:247:13: error: Usage of untyped name "charpoly" in typed context  [no-untyped-usage]
- sympy/matrices/eigen.py:247:24: error: Expression has type "Untyped"  [no-any-expr]

manticore (https://github.com/trailofbits/manticore)
- manticore/platforms/evm.py:3340:41: error: Incompatible types in assignment (expression has type "(Any, Any, Any, Any, Any, Any, Any, bool & None)", variable has type "None")  [assignment]
+ manticore/platforms/evm.py:3340:41: error: Incompatible types in assignment (expression has type "(Any, Any, Any, Any, Any, Any, Any, Never)", variable has type "None")  [assignment]
- manticore/platforms/evm.py:3376:9: error: No return value expected  [return-value]
+ manticore/platforms/evm.py:3376:9: error: Returning Any from function declared to return "None"  [no-any-return]

sphinx (https://github.com/sphinx-doc/sphinx)
+ sphinx/util/typing.py:215:39: error: "Never" has no attribute "__forward_arg__"  [attr-defined]

schema_salad (https://github.com/common-workflow-language/schema_salad)
+ schema_salad/schema.py:532:16: error: Need type annotation for "avro"  [var-annotated]
+ schema_salad/schema.py:532:16: note: See https://kotlinisland.github.io/basedmypy/_refs.html#code-var-annotated for more info
- schema_salad/tests/test_cg.py:89:1: note: See https://kotlinisland.github.io/basedmypy/_refs.html#code-var-annotated for more info

yarl (https://github.com/aio-libs/yarl)
- tests/test_url.py: note: In function "test_url_is_not_str":
- tests/test_url.py:48:27: error: Intersection of "URL & str" cannot exist: would have incompatible method signatures  [unreachable]
- tests/test_url.py:48:27: note: See https://kotlinisland.github.io/basedmypy/_refs.html#code-unreachable for more info
+ yarl/_url.py:386:9: note: See https://kotlinisland.github.io/basedmypy/_refs.html#code-unreachable for more info

spark (https://github.com/apache/spark)
- python/pyspark/pandas/generic.py:786:25: error: Intersection of "bool & list[Any]" cannot exist: would have incompatible method signatures  [unreachable]

dulwich (https://github.com/dulwich/dulwich)
- dulwich/repo.py:1034:36: error: Intersection of "bool & str" cannot exist: would have incompatible method signatures  [unreachable]