def compute_subst(self, node, formal_args, arg_dict, view):
"""Compute information about type parameters using one-way unification.
Given the arguments of a function call, try to find a substitution that
matches them against the specified formal parameters.
Args:
node: The current CFG node.
formal_args: An iterable of (name, value) pairs of formal arguments.
arg_dict: A map of strings to pytd.Bindings instances.
view: A mapping of Variable to Value.
Returns:
A tuple (subst, name), with "subst" the datatypes.HashableDict if we found
a working substition, None otherwise, and "name" the bad parameter in case
subst=None.
"""
if not arg_dict:
# A call with no arguments always succeeds.
assert not formal_args
return datatypes.HashableDict(), None
subst = {}
self._set_error_subst(None)
for name, formal in formal_args:
actual = arg_dict[name]
subst = self._match_value_against_type(actual, formal, subst, node, view)
if subst is None:
formal = self.vm.annotations_util.sub_one_annotation(
node, formal, [self._error_subst or {}])
return None, abstract.BadParam(name=name, expected=formal)
return datatypes.HashableDict(subst), None
def compute_subst(self, node, formal_args, arg_dict, view, alias_map=None):
"""Compute information about type parameters using one-way unification.
Given the arguments of a function call, try to find a substitution that
matches them against the specified formal parameters.
Args:
node: The current CFG node.
formal_args: An iterable of (name, value) pairs of formal arguments.
arg_dict: A map of strings to pytd.Bindings instances.
view: A mapping of Variable to Value.
alias_map: Optionally, a datatypes.UnionFind, which stores all the type
renaming information, mapping of type parameter name to its
representative.
Returns:
A tuple (subst, name), with "subst" the datatypes.HashableDict if we found
a working substition, None otherwise, and "name" the bad parameter in case
subst=None.
"""
if not arg_dict:
# A call with no arguments always succeeds.
assert not formal_args
return datatypes.AliasingDict(), None
subst = datatypes.AliasingDict()
if alias_map:
subst.uf = alias_map
self._set_error_subst(None)
self_subst = None
for name, formal in formal_args:
actual = arg_dict[name]
subst = self._match_value_against_type(actual, formal, subst, node, view)
if subst is None:
formal = self.vm.annotations_util.sub_one_annotation(
node, formal, [self._error_subst or {}])
return None, function.BadParam(name=name, expected=formal)
if name == "self":
self_subst = subst
if self_subst:
# Type parameters matched from a 'self' arg are class parameters whose
# values have been declared by the user, e.g.:
# x = Container[int](__any_object__)
# We should keep the 'int' value rather than using Union[int, Unknown].
for name, value in self_subst.items():
if any(not isinstance(v, abstract.Empty) for v in value.data):
subst[name] = value
return datatypes.HashableDict(subst), None
