(self, t: Overloaded)
| 415 | return join_types(t.fallback, self.s) |
| 416 | |
| 417 | def visit_overloaded(self, t: Overloaded) -> ProperType: |
| 418 | # This is more complex than most other cases. Here are some |
| 419 | # examples that illustrate how this works. |
| 420 | # |
| 421 | # First let's define a concise notation: |
| 422 | # - Cn are callable types (for n in 1, 2, ...) |
| 423 | # - Ov(C1, C2, ...) is an overloaded type with items C1, C2, ... |
| 424 | # - Callable[[T, ...], S] is written as [T, ...] -> S. |
| 425 | # |
| 426 | # We want some basic properties to hold (assume Cn are all |
| 427 | # unrelated via Any-similarity): |
| 428 | # |
| 429 | # join(Ov(C1, C2), C1) == C1 |
| 430 | # join(Ov(C1, C2), Ov(C1, C2)) == Ov(C1, C2) |
| 431 | # join(Ov(C1, C2), Ov(C1, C3)) == C1 |
| 432 | # join(Ov(C2, C2), C3) == join of fallback types |
| 433 | # |
| 434 | # The presence of Any types makes things more interesting. The join is the |
| 435 | # most general type we can get with respect to Any: |
| 436 | # |
| 437 | # join(Ov([int] -> int, [str] -> str), [Any] -> str) == Any -> str |
| 438 | # |
| 439 | # We could use a simplification step that removes redundancies, but that's not |
| 440 | # implemented right now. Consider this example, where we get a redundancy: |
| 441 | # |
| 442 | # join(Ov([int, Any] -> Any, [str, Any] -> Any), [Any, int] -> Any) == |
| 443 | # Ov([Any, int] -> Any, [Any, int] -> Any) |
| 444 | # |
| 445 | # TODO: Consider more cases of callable subtyping. |
| 446 | result: list[CallableType] = [] |
| 447 | s = self.s |
| 448 | if isinstance(s, FunctionLike): |
| 449 | # The interesting case where both types are function types. |
| 450 | for t_item in t.items: |
| 451 | for s_item in s.items: |
| 452 | if is_similar_callables(t_item, s_item): |
| 453 | if is_equivalent(t_item, s_item): |
| 454 | result.append(combine_similar_callables(t_item, s_item)) |
| 455 | elif is_subtype(t_item, s_item): |
| 456 | result.append(s_item) |
| 457 | if result: |
| 458 | # TODO: Simplify redundancies from the result. |
| 459 | if len(result) == 1: |
| 460 | return result[0] |
| 461 | else: |
| 462 | return Overloaded(result) |
| 463 | return join_types(t.fallback, s.fallback) |
| 464 | elif isinstance(s, Instance) and s.type.is_protocol: |
| 465 | call = unpack_callback_protocol(s) |
| 466 | if call: |
| 467 | return join_types(t, call) |
| 468 | return join_types(t.fallback, s) |
| 469 | |
| 470 | def join_tuples(self, s: TupleType, t: TupleType) -> list[Type] | None: |
| 471 | """Join two tuple types while handling variadic entries. |
nothing calls this directly
no test coverage detected