def assignment_to_list_does_not_allow_supertype():
target_sequence_node = nodes.ref("x")
value_node = nodes.ref("y")
node = nodes.assign([nodes.subscript(target_sequence_node, nodes.int_literal(0))], value_node)
type_bindings = {
"x": types.list_type(types.str_type),
"y": types.object_type,
}
try:
update_context(node, type_bindings=type_bindings)
assert False, "Expected error"
except errors.UnexpectedTargetTypeError as error:
assert_equal(target_sequence_node, ephemeral.root_node(error.node))
assert_equal(
ephemeral.FormalArg(ephemeral.attr(target_sequence_node, "__setitem__"), 1),
ephemeral.underlying_node(error.node)
)
assert_equal(types.object_type, error.value_type)
assert_equal(types.str_type, error.target_type)
def for_statement_target_cannot_be_strict_subtype_of_iterable_element_type():
target_sequence_node = nodes.ref("ys")
target_node = nodes.subscript(target_sequence_node, nodes.int_literal(0))
iterable_node = nodes.ref("xs")
node = nodes.for_(target_node, iterable_node, [])
try:
update_context(node, type_bindings={
"xs": types.list_type(types.object_type),
"ys": types.list_type(types.int_type),
})
assert False, "Expected error"
except errors.UnexpectedTargetTypeError as error:
assert_equal(target_sequence_node, ephemeral.root_node(error.node))
assert_equal(
ephemeral.FormalArg(ephemeral.attr(target_sequence_node, "__setitem__"), 1),
ephemeral.underlying_node(error.node)
)
assert_equal(types.object_type, error.value_type)
assert_equal(types.int_type, error.target_type)
def for_statement_requires_iterable_getitem_method_to_accept_integers():
cls = types.class_type("Blah")
cls.attrs.add("__getitem__", types.func([types.str_type], types.str_type))
ref_node = nodes.ref("xs")
node = nodes.for_(nodes.ref("x"), ref_node, [])
type_bindings = {
"xs": cls,
}
try:
update_context(node, type_bindings=type_bindings)
assert False, "Expected error"
except errors.UnexpectedTargetTypeError as error:
assert_equal(ref_node, ephemeral.root_node(error.node))
assert_equal(
ephemeral.FormalArg(ephemeral.attr(ref_node, "__getitem__"), 0),
ephemeral.underlying_node(error.node)
)
assert_equal(types.int_type, error.value_type)
assert_equal(types.str_type, error.target_type)