Class TypeVarId

mypy/types.py:524–587

class TypeVarId:
    # A type variable is uniquely identified by its raw id and meta level.

    # For plain variables (type parameters of generic classes and
    # functions) raw ids are allocated by semantic analysis, using
    # positive ids 1, 2, ... for generic class parameters and negative
    # ids -1, ... for generic function type arguments. A special value 0
    # is reserved for Self type variable (autogenerated). This convention
    # is only used to keep type variable ids distinct when allocating
    # them; the type checker makes no distinction between class and
    # function type variables.

    # Metavariables are allocated unique ids starting from 1.
    raw_id: Final[int]

    # Level of the variable in type inference. Currently either 0 for
    # declared types, or 1 for type inference metavariables.
    meta_level: int = 0

    # Class variable used for allocating fresh ids for metavariables.
    next_raw_id: ClassVar[int] = 1

    # Fullname of class or function/method which declares this type
    # variable (not the fullname of the TypeVar definition!), or ''
    namespace: str

    def __init__(self, raw_id: int, meta_level: int = 0, *, namespace: str = "") -> None:
        self.raw_id = raw_id
        self.meta_level = meta_level
        self.namespace = namespace

    @staticmethod
    def new(meta_level: int) -> TypeVarId:
        raw_id = TypeVarId.next_raw_id
        TypeVarId.next_raw_id += 1
        return TypeVarId(raw_id, meta_level)

    def __repr__(self) -> str:
        return self.raw_id.__repr__()

    def __eq__(self, other: object) -> bool:
        # Although this call is not expensive (like UnionType or TypedDictType),
        # most of the time we get the same object here, so add a fast path.
        if self is other:
            return True
        return (
            isinstance(other, TypeVarId)
            and self.raw_id == other.raw_id
            and self.meta_level == other.meta_level
            and self.namespace == other.namespace
        )

    def __ne__(self, other: object) -> bool:
        return not (self == other)

    def __hash__(self) -> int:
        return self.raw_id ^ (self.meta_level << 8) ^ hash(self.namespace)