def false_only(t: Type) -> ProperType:
"""
Restricted version of t with only False-ish values
"""
t = get_proper_type(t)
if not t.can_be_false:
if state.strict_optional:
# All values of t are True-ish, so there are no false values in it
return UninhabitedType(line=t.line)
else:
# When strict optional checking is disabled, everything can be
# False-ish since anything can be None
return NoneType(line=t.line)
elif not t.can_be_true:
# All values of t are already False-ish, so false_only is idempotent in this case
return t
elif isinstance(t, UnionType):
# The false version of a union type is the union of the false versions of its components
new_items = [false_only(item) for item in t.items]
can_be_false_items = [item for item in new_items if item.can_be_false]
return make_simplified_union(can_be_false_items,
line=t.line,
column=t.column)
else:
ret_type = _get_type_special_method_bool_ret_type(t)
if ret_type and ret_type.can_be_true and not ret_type.can_be_false:
new_t = copy_type(t)
new_t.can_be_false = False
return new_t
new_t = copy_type(t)
new_t.can_be_true = False
return new_t
def true_only(t: Type) -> ProperType:
"""
Restricted version of t with only True-ish values
"""
t = get_proper_type(t)
if not t.can_be_true:
# All values of t are False-ish, so there are no true values in it
return UninhabitedType(line=t.line, column=t.column)
elif not t.can_be_false:
# All values of t are already True-ish, so true_only is idempotent in this case
return t
elif isinstance(t, UnionType):
# The true version of a union type is the union of the true versions of its components
new_items = [true_only(item) for item in t.items]
can_be_true_items = [item for item in new_items if item.can_be_true]
return make_simplified_union(can_be_true_items,
line=t.line,
column=t.column)
else:
ret_type = _get_type_special_method_bool_ret_type(t)
if ret_type and ret_type.can_be_false and not ret_type.can_be_true:
new_t = copy_type(t)
new_t.can_be_true = False
return new_t
new_t = copy_type(t)
new_t.can_be_false = False
return new_t
def true_or_false(t: Type) -> ProperType:
"""
Unrestricted version of t with both True-ish and False-ish values
"""
t = get_proper_type(t)
if isinstance(t, UnionType):
new_items = [true_or_false(item) for item in t.items]
return make_simplified_union(new_items, line=t.line, column=t.column)
new_t = copy_type(t)
new_t.can_be_true = new_t.can_be_true_default()
new_t.can_be_false = new_t.can_be_false_default()
return new_t
