def map_type_from_supertype(typ: Type, sub_info: TypeInfo,
super_info: TypeInfo) -> Type:
"""Map type variables in a type defined in a supertype context to be valid
in the subtype context. Assume that the result is unique; if more than
one type is possible, return one of the alternatives.
For example, assume
. class D(Generic[S]) ...
. class C(D[E[T]], Generic[T]) ...
Now S in the context of D would be mapped to E[T] in the context of C.
"""
# Create the type of self in subtype, of form t[a1, ...].
inst_type = fill_typevars(sub_info)
if isinstance(inst_type, TupleType):
inst_type = inst_type.fallback
# Map the type of self to supertype. This gets us a description of the
# supertype type variables in terms of subtype variables, i.e. t[t1, ...]
# so that any type variables in tN are to be interpreted in subtype
# context.
inst_type = map_instance_to_supertype(inst_type, super_info)
# Finally expand the type variables in type with those in the previously
# constructed type. Note that both type and inst_type may have type
# variables, but in type they are interpreted in supertype context while
# in inst_type they are interpreted in subtype context. This works even if
# the names of type variables in supertype and subtype overlap.
return expand_type_by_instance(typ, inst_type)
def map_type_from_supertype(typ: Type, sub_info: TypeInfo,
super_info: TypeInfo) -> Type:
"""Map type variables in a type defined in a supertype context to be valid
in the subtype context. Assume that the result is unique; if more than
one type is possible, return one of the alternatives.
For example, assume
. class D(Generic[S]) ...
. class C(D[E[T]], Generic[T]) ...
Now S in the context of D would be mapped to E[T] in the context of C.
"""
# Create the type of self in subtype, of form t[a1, ...].
inst_type = fill_typevars(sub_info)
if isinstance(inst_type, TupleType):
inst_type = inst_type.fallback
# Map the type of self to supertype. This gets us a description of the
# supertype type variables in terms of subtype variables, i.e. t[t1, ...]
# so that any type variables in tN are to be interpreted in subtype
# context.
inst_type = map_instance_to_supertype(inst_type, super_info)
# Finally expand the type variables in type with those in the previously
# constructed type. Note that both type and inst_type may have type
# variables, but in type they are interpreted in supertype context while
# in inst_type they are interpreted in subtype context. This works even if
# the names of type variables in supertype and subtype overlap.
return expand_type_by_instance(typ, inst_type)
def class_callable(init_type: CallableType, info: TypeInfo, type_type: Instance,
special_sig: Optional[str]) -> CallableType:
"""Create a type object type based on the signature of __init__."""
variables = [] # type: List[TypeVarDef]
variables.extend(info.defn.type_vars)
variables.extend(init_type.variables)
callable_type = init_type.copy_modified(
ret_type=fill_typevars(info), fallback=type_type, name=None, variables=variables,
special_sig=special_sig)
c = callable_type.with_name('"{}"'.format(info.name()))
c.is_classmethod_class = True
return c
def class_callable(init_type: CallableType, info: TypeInfo,
type_type: Instance,
special_sig: Optional[str]) -> CallableType:
"""Create a type object type based on the signature of __init__."""
variables = [] # type: List[TypeVarDef]
variables.extend(info.defn.type_vars)
variables.extend(init_type.variables)
callable_type = init_type.copy_modified(ret_type=fill_typevars(info),
fallback=type_type,
name=None,
variables=variables,
special_sig=special_sig)
c = callable_type.with_name('"{}"'.format(info.name()))
c.is_classmethod_class = True
return c