def visit_newtype_expr(self, node: NewTypeExpr) -> NewTypeExpr:
res = NewTypeExpr(node.name,
node.old_type,
line=node.line,
column=node.column)
res.info = node.info
return res
def process_newtype_declaration(self, s: AssignmentStmt) -> None:
"""Check if s declares a NewType; if yes, store it in symbol table."""
# Extract and check all information from newtype declaration
name, call = self.analyze_newtype_declaration(s)
if name is None or call is None:
return
old_type = self.check_newtype_args(name, call, s)
call.analyzed = NewTypeExpr(name,
old_type,
line=call.line,
column=call.column)
if old_type is None:
return
# Create the corresponding class definition if the aliased type is subtypeable
if isinstance(old_type, TupleType):
newtype_class_info = self.build_newtype_typeinfo(
name, old_type, old_type.partial_fallback)
newtype_class_info.tuple_type = old_type
elif isinstance(old_type, Instance):
if old_type.type.is_protocol:
self.fail("NewType cannot be used with protocol classes", s)
newtype_class_info = self.build_newtype_typeinfo(
name, old_type, old_type)
else:
message = "Argument 2 to NewType(...) must be subclassable (got {})"
self.fail(message.format(self.msg.format(old_type)), s)
return
check_for_explicit_any(old_type,
self.options,
self.api.is_typeshed_stub_file,
self.msg,
context=s)
if self.options.disallow_any_unimported and has_any_from_unimported_type(
old_type):
self.msg.unimported_type_becomes_any("Argument 2 to NewType(...)",
old_type, s)
# If so, add it to the symbol table.
node = self.api.lookup(name, s)
if node is None:
self.fail("Could not find {} in current namespace".format(name), s)
return
# TODO: why does NewType work in local scopes despite always being of kind GDEF?
node.kind = GDEF
call.analyzed.info = node.node = newtype_class_info
def process_newtype_declaration(self, s: AssignmentStmt) -> bool:
"""Check if s declares a NewType; if yes, store it in symbol table.
Return True if it's a NewType declaration. The current target may be
deferred as a side effect if the base type is not ready, even if
the return value is True.
The logic in this function mostly copies the logic for visit_class_def()
with a single (non-Generic) base.
"""
name, call = self.analyze_newtype_declaration(s)
if name is None or call is None:
return False
# OK, now we know this is a NewType. But the base type may be not ready yet,
# add placeholder as we do for ClassDef.
fullname = self.api.qualified_name(name)
if (not call.analyzed or isinstance(call.analyzed, NewTypeExpr)
and not call.analyzed.info):
# Start from labeling this as a future class, as we do for normal ClassDefs.
placeholder = PlaceholderNode(fullname,
s,
s.line,
becomes_typeinfo=True)
self.api.add_symbol(name, placeholder, s, can_defer=False)
old_type, should_defer = self.check_newtype_args(name, call, s)
if not call.analyzed:
call.analyzed = NewTypeExpr(name,
old_type,
line=call.line,
column=call.column)
if old_type is None:
if should_defer:
# Base type is not ready.
self.api.defer()
return True
# Create the corresponding class definition if the aliased type is subtypeable
if isinstance(old_type, TupleType):
newtype_class_info = self.build_newtype_typeinfo(
name, old_type, old_type.partial_fallback)
newtype_class_info.tuple_type = old_type
elif isinstance(old_type, Instance):
if old_type.type.is_protocol:
self.fail("NewType cannot be used with protocol classes", s)
newtype_class_info = self.build_newtype_typeinfo(
name, old_type, old_type)
else:
if old_type is not None:
message = "Argument 2 to NewType(...) must be subclassable (got {})"
self.fail(message.format(self.msg.format(old_type)), s)
# Otherwise the error was already reported.
old_type = AnyType(TypeOfAny.from_error)
object_type = self.api.named_type('__builtins__.object')
newtype_class_info = self.build_newtype_typeinfo(
name, old_type, object_type)
newtype_class_info.fallback_to_any = True
check_for_explicit_any(old_type,
self.options,
self.api.is_typeshed_stub_file,
self.msg,
context=s)
if self.options.disallow_any_unimported and has_any_from_unimported_type(
old_type):
self.msg.unimported_type_becomes_any("Argument 2 to NewType(...)",
old_type, s)
# If so, add it to the symbol table.
assert isinstance(call.analyzed, NewTypeExpr)
# As we do for normal classes, create the TypeInfo only once, then just
# update base classes on next iterations (to get rid of placeholders there).
if not call.analyzed.info:
call.analyzed.info = newtype_class_info
else:
call.analyzed.info.bases = newtype_class_info.bases
self.api.add_symbol(name, call.analyzed.info, s)
newtype_class_info.line = s.line
return True
def visit_newtype_expr(self, node: NewTypeExpr) -> NewTypeExpr:
return NewTypeExpr(node.info)