# Calling builtins ## `bool` with incorrect arguments ```py class NotBool: __bool__ = None # error: [too-many-positional-arguments] "Too many positional arguments to class `bool`: expected 1, got 2" bool(1, 2) # TODO: We should emit an `unsupported-bool-conversion` error here because the argument doesn't implement `__bool__` correctly. bool(NotBool()) ``` ## Calls to `type()` A single-argument call to `type()` returns an object that has the argument's meta-type. (This is tested more extensively in `crates/ty_python_semantic/resources/mdtest/attributes.md`, alongside the tests for the `__class__` attribute.) ```py reveal_type(type(1)) # revealed: Literal[int] ``` But a three-argument call to type creates a dynamic instance of the `type` class: ```py class Base: ... reveal_type(type("Foo", (), {})) # revealed: type reveal_type(type("Foo", (Base,), {"attr": 1})) # revealed: type ``` Other numbers of arguments are invalid ```py # error: [no-matching-overload] "No overload of class `type` matches arguments" type("Foo", ()) # error: [no-matching-overload] "No overload of class `type` matches arguments" type("Foo", (), {}, weird_other_arg=42) ``` The following calls are also invalid, due to incorrect argument types: ```py class Base: ... # error: [no-matching-overload] "No overload of class `type` matches arguments" type(b"Foo", (), {}) # error: [no-matching-overload] "No overload of class `type` matches arguments" type("Foo", Base, {}) # TODO: this should be an error type("Foo", (1, 2), {}) # TODO: this should be an error type("Foo", (Base,), {b"attr": 1}) ``` ## Calls to `str()` ### Valid calls ```py str() str("") str(b"") str(1) str(object=1) str(b"M\xc3\xbcsli", "utf-8") str(b"M\xc3\xbcsli", "utf-8", "replace") str(b"M\x00\xfc\x00s\x00l\x00i\x00", encoding="utf-16") str(b"M\x00\xfc\x00s\x00l\x00i\x00", encoding="utf-16", errors="ignore") str(bytearray.fromhex("4d c3 bc 73 6c 69"), "utf-8") str(bytearray(), "utf-8") str(encoding="utf-8", object=b"M\xc3\xbcsli") str(b"", errors="replace") str(encoding="utf-8") str(errors="replace") ``` ### Invalid calls ```py str(1, 2) # error: [no-matching-overload] str(o=1) # error: [no-matching-overload] # First argument is not a bytes-like object: str("Müsli", "utf-8") # error: [no-matching-overload] # Second argument is not a valid encoding: str(b"M\xc3\xbcsli", b"utf-8") # error: [no-matching-overload] ```