interpreter: Split decorators from interpreterbase.py

3 files changed, 576 insertions, 561 deletions

diff --git a/mesonbuild/interpreterbase/__init__.py b/mesonbuild/interpreterbase/__init__.py
index 5f33848..d5ef367 100644
--- a/mesonbuild/interpreterbase/__init__.py
+++ b/mesonbuild/interpreterbase/__init__.py
@@ -79,21 +79,7 @@ from .baseobjects import (
     TYPE_key_resolver,
 )
 
-from .exceptions import (
-    InterpreterException,
-    InvalidCode,
-    InvalidArguments,
-    SubdirDoneRequest,
-    ContinueRequest,
-    BreakRequest,
-)
-
-from .disabler import Disabler, is_disabled
-from .helpers import check_stringlist, default_resolve_key, flatten
-
-from .interpreterbase import (
-    MesonVersionString,
-
+from .decorators import (
     noPosargs,
     builtinMethodNoKwargs,
     noKwargs,
@@ -109,6 +95,17 @@ from .interpreterbase import (
     FeatureDeprecated,
     FeatureNewKwargs,
     FeatureDeprecatedKwargs,
+)
 
-    InterpreterBase,
+from .exceptions import (
+    InterpreterException,
+    InvalidCode,
+    InvalidArguments,
+    SubdirDoneRequest,
+    ContinueRequest,
+    BreakRequest,
 )
+
+from .disabler import Disabler, is_disabled
+from .helpers import check_stringlist, default_resolve_key, flatten
+from .interpreterbase import MesonVersionString, InterpreterBase
diff --git a/mesonbuild/interpreterbase/decorators.py b/mesonbuild/interpreterbase/decorators.py
new file mode 100644
index 0000000..f997111
--- /dev/null
+++ b/mesonbuild/interpreterbase/decorators.py
@@ -0,0 +1,561 @@
+# Copyright 2013-2021 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .. import mesonlib, mlog
+from .baseobjects import TV_func, TYPE_nvar
+from .disabler import Disabler
+from .exceptions import InterpreterException, InvalidArguments
+from .helpers import check_stringlist, get_callee_args
+
+from functools import wraps
+import abc
+import itertools
+import typing as T
+
+def noPosargs(f: TV_func) -> TV_func:
+    @wraps(f)
+    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+        args = get_callee_args(wrapped_args)[2]
+        if args:
+            raise InvalidArguments('Function does not take positional arguments.')
+        return f(*wrapped_args, **wrapped_kwargs)
+    return T.cast(TV_func, wrapped)
+
+def builtinMethodNoKwargs(f: TV_func) -> TV_func:
+    @wraps(f)
+    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+        node = wrapped_args[0].current_node
+        method_name = wrapped_args[2]
+        kwargs = wrapped_args[4]
+        if kwargs:
+            mlog.warning(f'Method {method_name!r} does not take keyword arguments.',
+                         'This will become a hard error in the future',
+                         location=node)
+        return f(*wrapped_args, **wrapped_kwargs)
+    return T.cast(TV_func, wrapped)
+
+def noKwargs(f: TV_func) -> TV_func:
+    @wraps(f)
+    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+        kwargs = get_callee_args(wrapped_args)[3]
+        if kwargs:
+            raise InvalidArguments('Function does not take keyword arguments.')
+        return f(*wrapped_args, **wrapped_kwargs)
+    return T.cast(TV_func, wrapped)
+
+def stringArgs(f: TV_func) -> TV_func:
+    @wraps(f)
+    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+        args = get_callee_args(wrapped_args)[2]
+        assert(isinstance(args, list))
+        check_stringlist(args)
+        return f(*wrapped_args, **wrapped_kwargs)
+    return T.cast(TV_func, wrapped)
+
+def noArgsFlattening(f: TV_func) -> TV_func:
+    setattr(f, 'no-args-flattening', True)  # noqa: B010
+    return f
+
+def disablerIfNotFound(f: TV_func) -> TV_func:
+    @wraps(f)
+    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+        kwargs = get_callee_args(wrapped_args)[3]
+        disabler = kwargs.pop('disabler', False)
+        ret = f(*wrapped_args, **wrapped_kwargs)
+        if disabler and not ret.held_object.found():
+            return Disabler()
+        return ret
+    return T.cast(TV_func, wrapped)
+
+class permittedKwargs:
+
+    def __init__(self, permitted: T.Set[str]):
+        self.permitted = permitted  # type: T.Set[str]
+
+    def __call__(self, f: TV_func) -> TV_func:
+        @wraps(f)
+        def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+            s, node, args, kwargs, _ = get_callee_args(wrapped_args)
+            for k in kwargs:
+                if k not in self.permitted:
+                    mlog.warning(f'''Passed invalid keyword argument "{k}".''', location=node)
+                    mlog.warning('This will become a hard error in the future.')
+            return f(*wrapped_args, **wrapped_kwargs)
+        return T.cast(TV_func, wrapped)
+
+
+def typed_pos_args(name: str, *types: T.Union[T.Type, T.Tuple[T.Type, ...]],
+                   varargs: T.Optional[T.Union[T.Type, T.Tuple[T.Type, ...]]] = None,
+                   optargs: T.Optional[T.List[T.Union[T.Type, T.Tuple[T.Type, ...]]]] = None,
+                   min_varargs: int = 0, max_varargs: int = 0) -> T.Callable[..., T.Any]:
+    """Decorator that types type checking of positional arguments.
+
+    This supports two different models of optional aguments, the first is the
+    variadic argument model. Variadic arguments are a possibly bounded,
+    possibly unbounded number of arguments of the same type (unions are
+    supported). The second is the standard default value model, in this case
+    a number of optional arguments may be provided, but they are still
+    ordered, and they may have different types.
+
+    This function does not support mixing variadic and default arguments.
+
+    :name: The name of the decorated function (as displayed in error messages)
+    :varargs: They type(s) of any variadic arguments the function takes. If
+        None the function takes no variadic args
+    :min_varargs: the minimum number of variadic arguments taken
+    :max_varargs: the maximum number of variadic arguments taken. 0 means unlimited
+    :optargs: The types of any optional arguments parameters taken. If None
+        then no optional paramters are taken.
+
+    Some examples of usage blow:
+    >>> @typed_pos_args('mod.func', str, (str, int))
+    ... def func(self, state: ModuleState, args: T.Tuple[str, T.Union[str, int]], kwargs: T.Dict[str, T.Any]) -> T.Any:
+    ...     pass
+
+    >>> @typed_pos_args('method', str, varargs=str)
+    ... def method(self, node: BaseNode, args: T.Tuple[str, T.List[str]], kwargs: T.Dict[str, T.Any]) -> T.Any:
+    ...     pass
+
+    >>> @typed_pos_args('method', varargs=str, min_varargs=1)
+    ... def method(self, node: BaseNode, args: T.Tuple[T.List[str]], kwargs: T.Dict[str, T.Any]) -> T.Any:
+    ...     pass
+
+    >>> @typed_pos_args('method', str, optargs=[(str, int), str])
+    ... def method(self, node: BaseNode, args: T.Tuple[str, T.Optional[T.Union[str, int]], T.Optional[str]], kwargs: T.Dict[str, T.Any]) -> T.Any:
+    ...     pass
+
+    When should you chose `typed_pos_args('name', varargs=str,
+    min_varargs=1)` vs `typed_pos_args('name', str, varargs=str)`?
+
+    The answer has to do with the semantics of the function, if all of the
+    inputs are the same type (such as with `files()`) then the former is
+    correct, all of the arguments are string names of files. If the first
+    argument is something else the it should be separated.
+    """
+    def inner(f: TV_func) -> TV_func:
+
+        @wraps(f)
+        def wrapper(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+            args = get_callee_args(wrapped_args)[2]
+
+            # These are implementation programming errors, end users should never see them.
+            assert isinstance(args, list), args
+            assert max_varargs >= 0, 'max_varags cannot be negative'
+            assert min_varargs >= 0, 'min_varags cannot be negative'
+            assert optargs is None or varargs is None, \
+                'varargs and optargs not supported together as this would be ambiguous'
+
+            num_args = len(args)
+            num_types = len(types)
+            a_types = types
+
+            if varargs:
+                min_args = num_types + min_varargs
+                max_args = num_types + max_varargs
+                if max_varargs == 0 and num_args < min_args:
+                    raise InvalidArguments(f'{name} takes at least {min_args} arguments, but got {num_args}.')
+                elif max_varargs != 0 and (num_args < min_args or num_args > max_args):
+                    raise InvalidArguments(f'{name} takes between {min_args} and {max_args} arguments, but got {num_args}.')
+            elif optargs:
+                if num_args < num_types:
+                    raise InvalidArguments(f'{name} takes at least {num_types} arguments, but got {num_args}.')
+                elif num_args > num_types + len(optargs):
+                    raise InvalidArguments(f'{name} takes at most {num_types + len(optargs)} arguments, but got {num_args}.')
+                # Add the number of positional arguments required
+                if num_args > num_types:
+                    diff = num_args - num_types
+                    a_types = tuple(list(types) + list(optargs[:diff]))
+            elif num_args != num_types:
+                raise InvalidArguments(f'{name} takes exactly {num_types} arguments, but got {num_args}.')
+
+            for i, (arg, type_) in enumerate(itertools.zip_longest(args, a_types, fillvalue=varargs), start=1):
+                if not isinstance(arg, type_):
+                    if isinstance(type_, tuple):
+                        shouldbe = 'one of: {}'.format(", ".join(f'"{t.__name__}"' for t in type_))
+                    else:
+                        shouldbe = f'"{type_.__name__}"'
+                    raise InvalidArguments(f'{name} argument {i} was of type "{type(arg).__name__}" but should have been {shouldbe}')
+
+            # Ensure that we're actually passing a tuple.
+            # Depending on what kind of function we're calling the length of
+            # wrapped_args can vary.
+            nargs = list(wrapped_args)
+            i = nargs.index(args)
+            if varargs:
+                # if we have varargs we need to split them into a separate
+                # tuple, as python's typing doesn't understand tuples with
+                # fixed elements and variadic elements, only one or the other.
+                # so in that case we need T.Tuple[int, str, float, T.Tuple[str, ...]]
+                pos = args[:len(types)]
+                var = list(args[len(types):])
+                pos.append(var)
+                nargs[i] = tuple(pos)
+            elif optargs:
+                if num_args < num_types + len(optargs):
+                    diff =  num_types + len(optargs) - num_args
+                    nargs[i] = tuple(list(args) + [None] * diff)
+                else:
+                    nargs[i] = args
+            else:
+                nargs[i] = tuple(args)
+            return f(*nargs, **wrapped_kwargs)
+
+        return T.cast(TV_func, wrapper)
+    return inner
+
+
+class ContainerTypeInfo:
+
+    """Container information for keyword arguments.
+
+    For keyword arguments that are containers (list or dict), this class encodes
+    that information.
+
+    :param container: the type of container
+    :param contains: the types the container holds
+    :param pairs: if the container is supposed to be of even length.
+        This is mainly used for interfaces that predate the addition of dictionaries, and use
+        `[key, value, key2, value2]` format.
+    :param allow_empty: Whether this container is allowed to be empty
+        There are some cases where containers not only must be passed, but must
+        not be empty, and other cases where an empty container is allowed.
+    """
+
+    def __init__(self, container: T.Type, contains: T.Union[T.Type, T.Tuple[T.Type, ...]], *,
+                 pairs: bool = False, allow_empty: bool = True) :
+        self.container = container
+        self.contains = contains
+        self.pairs = pairs
+        self.allow_empty = allow_empty
+
+    def check(self, value: T.Any) -> T.Optional[str]:
+        """Check that a value is valid.
+
+        :param value: A value to check
+        :return: If there is an error then a string message, otherwise None
+        """
+        if not isinstance(value, self.container):
+            return f'container type was "{type(value).__name__}", but should have been "{self.container.__name__}"'
+        iter_ = iter(value.values()) if isinstance(value, dict) else iter(value)
+        for each in iter_:
+            if not isinstance(each, self.contains):
+                if isinstance(self.contains, tuple):
+                    shouldbe = 'one of: {}'.format(", ".join(f'"{t.__name__}"' for t in self.contains))
+                else:
+                    shouldbe = f'"{self.contains.__name__}"'
+                return f'contained a value of type "{type(each).__name__}" but should have been {shouldbe}'
+        if self.pairs and len(value) % 2 != 0:
+            return 'container should be of even length, but is not'
+        if not value and not self.allow_empty:
+            return 'container is empty, but not allowed to be'
+        return None
+
+
+_T = T.TypeVar('_T')
+
+
+class KwargInfo(T.Generic[_T]):
+
+    """A description of a keyword argument to a meson function
+
+    This is used to describe a value to the :func:typed_kwargs function.
+
+    :param name: the name of the parameter
+    :param types: A type or tuple of types that are allowed, or a :class:ContainerType
+    :param required: Whether this is a required keyword argument. defaults to False
+    :param listify: If true, then the argument will be listified before being
+        checked. This is useful for cases where the Meson DSL allows a scalar or
+        a container, but internally we only want to work with containers
+    :param default: A default value to use if this isn't set. defaults to None,
+        this may be safely set to a mutable type, as long as that type does not
+        itself contain mutable types, typed_kwargs will copy the default
+    :param since: Meson version in which this argument has been added. defaults to None
+    :param deprecated: Meson version in which this argument has been deprecated. defaults to None
+    :param validator: A callable that does additional validation. This is mainly
+        intended for cases where a string is expected, but only a few specific
+        values are accepted. Must return None if the input is valid, or a
+        message if the input is invalid
+    :param convertor: A callable that converts the raw input value into a
+        different type. This is intended for cases such as the meson DSL using a
+        string, but the implementation using an Enum. This should not do
+        validation, just converstion.
+    """
+
+    def __init__(self, name: str, types: T.Union[T.Type[_T], T.Tuple[T.Type[_T], ...], ContainerTypeInfo],
+                 *, required: bool = False, listify: bool = False,
+                 default: T.Optional[_T] = None,
+                 since: T.Optional[str] = None,
+                 deprecated: T.Optional[str] = None,
+                 validator: T.Optional[T.Callable[[_T], T.Optional[str]]] = None,
+                 convertor: T.Optional[T.Callable[[_T], TYPE_nvar]] = None):
+        self.name = name
+        self.types = types
+        self.required = required
+        self.listify = listify
+        self.default = default
+        self.since = since
+        self.deprecated = deprecated
+        self.validator = validator
+        self.convertor = convertor
+
+
+def typed_kwargs(name: str, *types: KwargInfo) -> T.Callable[..., T.Any]:
+    """Decorator for type checking keyword arguments.
+
+    Used to wrap a meson DSL implementation function, where it checks various
+    things about keyword arguments, including the type, and various other
+    information. For non-required values it sets the value to a default, which
+    means the value will always be provided.
+
+    If type tyhpe is a :class:ContainerTypeInfo, then the default value will be
+    passed as an argument to the container initializer, making a shallow copy
+
+    :param name: the name of the function, including the object it's attached ot
+        (if applicable)
+    :param *types: KwargInfo entries for each keyword argument.
+    """
+    def inner(f: TV_func) -> TV_func:
+
+        @wraps(f)
+        def wrapper(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+            kwargs, subproject = get_callee_args(wrapped_args, want_subproject=True)[3:5]
+
+            all_names = {t.name for t in types}
+            unknowns = set(kwargs).difference(all_names)
+            if unknowns:
+                # Warn about unknown argumnts, delete them and continue. This
+                # keeps current behavior
+                ustr = ', '.join([f'"{u}"' for u in sorted(unknowns)])
+                mlog.warning(f'{name} got unknown keyword arguments {ustr}')
+                for u in unknowns:
+                    del kwargs[u]
+
+            for info in types:
+                value = kwargs.get(info.name)
+                if value is not None:
+                    if info.since:
+                        feature_name = info.name + ' arg in ' + name
+                        FeatureNew.single_use(feature_name, info.since, subproject)
+                    if info.deprecated:
+                        feature_name = info.name + ' arg in ' + name
+                        FeatureDeprecated.single_use(feature_name, info.deprecated, subproject)
+                    if info.listify:
+                        kwargs[info.name] = value = mesonlib.listify(value)
+                    if isinstance(info.types, ContainerTypeInfo):
+                        msg = info.types.check(value)
+                        if msg is not None:
+                            raise InvalidArguments(f'{name} keyword argument "{info.name}" {msg}')
+                    else:
+                        if not isinstance(value, info.types):
+                            if isinstance(info.types, tuple):
+                                shouldbe = 'one of: {}'.format(", ".join(f'"{t.__name__}"' for t in info.types))
+                            else:
+                                shouldbe = f'"{info.types.__name__}"'
+                            raise InvalidArguments(f'{name} keyword argument "{info.name}"" was of type "{type(value).__name__}" but should have been {shouldbe}')
+
+                    if info.validator is not None:
+                        msg = info.validator(value)
+                        if msg is not None:
+                            raise InvalidArguments(f'{name} keyword argument "{info.name}" {msg}')
+                elif info.required:
+                    raise InvalidArguments(f'{name} is missing required keyword argument "{info.name}"')
+                else:
+                    # set the value to the default, this ensuring all kwargs are present
+                    # This both simplifies the typing checking and the usage
+                    # Create a shallow copy of the container (and do a type
+                    # conversion if necessary). This allows mutable types to
+                    # be used safely as default values
+                    if isinstance(info.types, ContainerTypeInfo):
+                        kwargs[info.name] = info.types.container(info.default)
+                    else:
+                        kwargs[info.name] = info.default
+
+                if info.convertor:
+                    kwargs[info.name] = info.convertor(kwargs[info.name])
+
+            return f(*wrapped_args, **wrapped_kwargs)
+        return T.cast(TV_func, wrapper)
+    return inner
+
+
+class FeatureCheckBase(metaclass=abc.ABCMeta):
+    "Base class for feature version checks"
+
+    # In python 3.6 we can just forward declare this, but in 3.5 we can't
+    # This will be overwritten by the subclasses by necessity
+    feature_registry = {}  # type: T.ClassVar[T.Dict[str, T.Dict[str, T.Set[str]]]]
+
+    def __init__(self, feature_name: str, version: str, extra_message: T.Optional[str] = None):
+        self.feature_name = feature_name  # type: str
+        self.feature_version = version    # type: str
+        self.extra_message = extra_message or ''  # type: str
+
+    @staticmethod
+    def get_target_version(subproject: str) -> str:
+        # Don't do any checks if project() has not been parsed yet
+        if subproject not in mesonlib.project_meson_versions:
+            return ''
+        return mesonlib.project_meson_versions[subproject]
+
+    @staticmethod
+    @abc.abstractmethod
+    def check_version(target_version: str, feature_Version: str) -> bool:
+        pass
+
+    def use(self, subproject: str) -> None:
+        tv = self.get_target_version(subproject)
+        # No target version
+        if tv == '':
+            return
+        # Target version is new enough
+        if self.check_version(tv, self.feature_version):
+            return
+        # Feature is too new for target version, register it
+        if subproject not in self.feature_registry:
+            self.feature_registry[subproject] = {self.feature_version: set()}
+        register = self.feature_registry[subproject]
+        if self.feature_version not in register:
+            register[self.feature_version] = set()
+        if self.feature_name in register[self.feature_version]:
+            # Don't warn about the same feature multiple times
+            # FIXME: This is needed to prevent duplicate warnings, but also
+            # means we won't warn about a feature used in multiple places.
+            return
+        register[self.feature_version].add(self.feature_name)
+        self.log_usage_warning(tv)
+
+    @classmethod
+    def report(cls, subproject: str) -> None:
+        if subproject not in cls.feature_registry:
+            return
+        warning_str = cls.get_warning_str_prefix(cls.get_target_version(subproject))
+        fv = cls.feature_registry[subproject]
+        for version in sorted(fv.keys()):
+            warning_str += '\n * {}: {}'.format(version, fv[version])
+        mlog.warning(warning_str)
+
+    def log_usage_warning(self, tv: str) -> None:
+        raise InterpreterException('log_usage_warning not implemented')
+
+    @staticmethod
+    def get_warning_str_prefix(tv: str) -> str:
+        raise InterpreterException('get_warning_str_prefix not implemented')
+
+    def __call__(self, f: TV_func) -> TV_func:
+        @wraps(f)
+        def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+            subproject = get_callee_args(wrapped_args, want_subproject=True)[4]
+            if subproject is None:
+                raise AssertionError(f'{wrapped_args!r}')
+            self.use(subproject)
+            return f(*wrapped_args, **wrapped_kwargs)
+        return T.cast(TV_func, wrapped)
+
+    @classmethod
+    def single_use(cls, feature_name: str, version: str, subproject: str,
+                   extra_message: T.Optional[str] = None) -> None:
+        """Oneline version that instantiates and calls use()."""
+        cls(feature_name, version, extra_message).use(subproject)
+
+
+class FeatureNew(FeatureCheckBase):
+    """Checks for new features"""
+
+    # Class variable, shared across all instances
+    #
+    # Format: {subproject: {feature_version: set(feature_names)}}
+    feature_registry = {}  # type: T.ClassVar[T.Dict[str, T.Dict[str, T.Set[str]]]]
+
+    @staticmethod
+    def check_version(target_version: str, feature_version: str) -> bool:
+        return mesonlib.version_compare_condition_with_min(target_version, feature_version)
+
+    @staticmethod
+    def get_warning_str_prefix(tv: str) -> str:
+        return f'Project specifies a minimum meson_version \'{tv}\' but uses features which were added in newer versions:'
+
+    def log_usage_warning(self, tv: str) -> None:
+        args = [
+            'Project targeting', f"'{tv}'",
+            'but tried to use feature introduced in',
+            f"'{self.feature_version}':",
+            f'{self.feature_name}.',
+        ]
+        if self.extra_message:
+            args.append(self.extra_message)
+        mlog.warning(*args)
+
+class FeatureDeprecated(FeatureCheckBase):
+    """Checks for deprecated features"""
+
+    # Class variable, shared across all instances
+    #
+    # Format: {subproject: {feature_version: set(feature_names)}}
+    feature_registry = {}  # type: T.ClassVar[T.Dict[str, T.Dict[str, T.Set[str]]]]
+
+    @staticmethod
+    def check_version(target_version: str, feature_version: str) -> bool:
+        # For deprecation checks we need to return the inverse of FeatureNew checks
+        return not mesonlib.version_compare_condition_with_min(target_version, feature_version)
+
+    @staticmethod
+    def get_warning_str_prefix(tv: str) -> str:
+        return 'Deprecated features used:'
+
+    def log_usage_warning(self, tv: str) -> None:
+        args = [
+            'Project targeting', f"'{tv}'",
+            'but tried to use feature deprecated since',
+            f"'{self.feature_version}':",
+            f'{self.feature_name}.',
+        ]
+        if self.extra_message:
+            args.append(self.extra_message)
+        mlog.warning(*args)
+
+
+class FeatureCheckKwargsBase(metaclass=abc.ABCMeta):
+
+    @property
+    @abc.abstractmethod
+    def feature_check_class(self) -> T.Type[FeatureCheckBase]:
+        pass
+
+    def __init__(self, feature_name: str, feature_version: str,
+                 kwargs: T.List[str], extra_message: T.Optional[str] = None):
+        self.feature_name = feature_name
+        self.feature_version = feature_version
+        self.kwargs = kwargs
+        self.extra_message = extra_message
+
+    def __call__(self, f: TV_func) -> TV_func:
+        @wraps(f)
+        def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
+            kwargs, subproject = get_callee_args(wrapped_args, want_subproject=True)[3:5]
+            if subproject is None:
+                raise AssertionError(f'{wrapped_args!r}')
+            for arg in self.kwargs:
+                if arg not in kwargs:
+                    continue
+                name = arg + ' arg in ' + self.feature_name
+                self.feature_check_class.single_use(
+                        name, self.feature_version, subproject, self.extra_message)
+            return f(*wrapped_args, **wrapped_kwargs)
+        return T.cast(TV_func, wrapped)
+
+class FeatureNewKwargs(FeatureCheckKwargsBase):
+    feature_check_class = FeatureNew
+
+class FeatureDeprecatedKwargs(FeatureCheckKwargsBase):
+    feature_check_class = FeatureDeprecated
diff --git a/mesonbuild/interpreterbase/interpreterbase.py b/mesonbuild/interpreterbase/interpreterbase.py
index 8181a05..1e4be01 100644
--- a/mesonbuild/interpreterbase/interpreterbase.py
+++ b/mesonbuild/interpreterbase/interpreterbase.py
@@ -24,7 +24,6 @@ from .baseobjects import (
     ObjectHolder,
     RangeHolder,
 
-    TV_func,
     TYPE_var,
     TYPE_nvar,
     TYPE_nkwargs,
@@ -39,12 +38,10 @@ from .exceptions import (
     BreakRequest
 )
 
+from .decorators import FeatureNew, builtinMethodNoKwargs
 from .disabler import Disabler, is_disabled
-from .helpers import check_stringlist, default_resolve_key, flatten, get_callee_args
+from .helpers import check_stringlist, default_resolve_key, flatten
 
-from functools import wraps
-import abc
-import itertools
 import os, copy, re
 import typing as T
 
@@ -52,546 +49,6 @@ import typing as T
 class MesonVersionString(str):
     pass
 
-
-# Decorators for method calls.
-
-def noPosargs(f: TV_func) -> TV_func:
-    @wraps(f)
-    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        args = get_callee_args(wrapped_args)[2]
-        if args:
-            raise InvalidArguments('Function does not take positional arguments.')
-        return f(*wrapped_args, **wrapped_kwargs)
-    return T.cast(TV_func, wrapped)
-
-def builtinMethodNoKwargs(f: TV_func) -> TV_func:
-    @wraps(f)
-    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        node = wrapped_args[0].current_node
-        method_name = wrapped_args[2]
-        kwargs = wrapped_args[4]
-        if kwargs:
-            mlog.warning(f'Method {method_name!r} does not take keyword arguments.',
-                         'This will become a hard error in the future',
-                         location=node)
-        return f(*wrapped_args, **wrapped_kwargs)
-    return T.cast(TV_func, wrapped)
-
-def noKwargs(f: TV_func) -> TV_func:
-    @wraps(f)
-    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        kwargs = get_callee_args(wrapped_args)[3]
-        if kwargs:
-            raise InvalidArguments('Function does not take keyword arguments.')
-        return f(*wrapped_args, **wrapped_kwargs)
-    return T.cast(TV_func, wrapped)
-
-def stringArgs(f: TV_func) -> TV_func:
-    @wraps(f)
-    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        args = get_callee_args(wrapped_args)[2]
-        assert(isinstance(args, list))
-        check_stringlist(args)
-        return f(*wrapped_args, **wrapped_kwargs)
-    return T.cast(TV_func, wrapped)
-
-def noArgsFlattening(f: TV_func) -> TV_func:
-    setattr(f, 'no-args-flattening', True)  # noqa: B010
-    return f
-
-def disablerIfNotFound(f: TV_func) -> TV_func:
-    @wraps(f)
-    def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        kwargs = get_callee_args(wrapped_args)[3]
-        disabler = kwargs.pop('disabler', False)
-        ret = f(*wrapped_args, **wrapped_kwargs)
-        if disabler and not ret.held_object.found():
-            return Disabler()
-        return ret
-    return T.cast(TV_func, wrapped)
-
-class permittedKwargs:
-
-    def __init__(self, permitted: T.Set[str]):
-        self.permitted = permitted  # type: T.Set[str]
-
-    def __call__(self, f: TV_func) -> TV_func:
-        @wraps(f)
-        def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            s, node, args, kwargs, _ = get_callee_args(wrapped_args)
-            for k in kwargs:
-                if k not in self.permitted:
-                    mlog.warning(f'''Passed invalid keyword argument "{k}".''', location=node)
-                    mlog.warning('This will become a hard error in the future.')
-            return f(*wrapped_args, **wrapped_kwargs)
-        return T.cast(TV_func, wrapped)
-
-
-def typed_pos_args(name: str, *types: T.Union[T.Type, T.Tuple[T.Type, ...]],
-                   varargs: T.Optional[T.Union[T.Type, T.Tuple[T.Type, ...]]] = None,
-                   optargs: T.Optional[T.List[T.Union[T.Type, T.Tuple[T.Type, ...]]]] = None,
-                   min_varargs: int = 0, max_varargs: int = 0) -> T.Callable[..., T.Any]:
-    """Decorator that types type checking of positional arguments.
-
-    This supports two different models of optional aguments, the first is the
-    variadic argument model. Variadic arguments are a possibly bounded,
-    possibly unbounded number of arguments of the same type (unions are
-    supported). The second is the standard default value model, in this case
-    a number of optional arguments may be provided, but they are still
-    ordered, and they may have different types.
-
-    This function does not support mixing variadic and default arguments.
-
-    :name: The name of the decorated function (as displayed in error messages)
-    :varargs: They type(s) of any variadic arguments the function takes. If
-        None the function takes no variadic args
-    :min_varargs: the minimum number of variadic arguments taken
-    :max_varargs: the maximum number of variadic arguments taken. 0 means unlimited
-    :optargs: The types of any optional arguments parameters taken. If None
-        then no optional paramters are taken.
-
-    Some examples of usage blow:
-    >>> @typed_pos_args('mod.func', str, (str, int))
-    ... def func(self, state: ModuleState, args: T.Tuple[str, T.Union[str, int]], kwargs: T.Dict[str, T.Any]) -> T.Any:
-    ...     pass
-
-    >>> @typed_pos_args('method', str, varargs=str)
-    ... def method(self, node: BaseNode, args: T.Tuple[str, T.List[str]], kwargs: T.Dict[str, T.Any]) -> T.Any:
-    ...     pass
-
-    >>> @typed_pos_args('method', varargs=str, min_varargs=1)
-    ... def method(self, node: BaseNode, args: T.Tuple[T.List[str]], kwargs: T.Dict[str, T.Any]) -> T.Any:
-    ...     pass
-
-    >>> @typed_pos_args('method', str, optargs=[(str, int), str])
-    ... def method(self, node: BaseNode, args: T.Tuple[str, T.Optional[T.Union[str, int]], T.Optional[str]], kwargs: T.Dict[str, T.Any]) -> T.Any:
-    ...     pass
-
-    When should you chose `typed_pos_args('name', varargs=str,
-    min_varargs=1)` vs `typed_pos_args('name', str, varargs=str)`?
-
-    The answer has to do with the semantics of the function, if all of the
-    inputs are the same type (such as with `files()`) then the former is
-    correct, all of the arguments are string names of files. If the first
-    argument is something else the it should be separated.
-    """
-    def inner(f: TV_func) -> TV_func:
-
-        @wraps(f)
-        def wrapper(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            args = get_callee_args(wrapped_args)[2]
-
-            # These are implementation programming errors, end users should never see them.
-            assert isinstance(args, list), args
-            assert max_varargs >= 0, 'max_varags cannot be negative'
-            assert min_varargs >= 0, 'min_varags cannot be negative'
-            assert optargs is None or varargs is None, \
-                'varargs and optargs not supported together as this would be ambiguous'
-
-            num_args = len(args)
-            num_types = len(types)
-            a_types = types
-
-            if varargs:
-                min_args = num_types + min_varargs
-                max_args = num_types + max_varargs
-                if max_varargs == 0 and num_args < min_args:
-                    raise InvalidArguments(f'{name} takes at least {min_args} arguments, but got {num_args}.')
-                elif max_varargs != 0 and (num_args < min_args or num_args > max_args):
-                    raise InvalidArguments(f'{name} takes between {min_args} and {max_args} arguments, but got {num_args}.')
-            elif optargs:
-                if num_args < num_types:
-                    raise InvalidArguments(f'{name} takes at least {num_types} arguments, but got {num_args}.')
-                elif num_args > num_types + len(optargs):
-                    raise InvalidArguments(f'{name} takes at most {num_types + len(optargs)} arguments, but got {num_args}.')
-                # Add the number of positional arguments required
-                if num_args > num_types:
-                    diff = num_args - num_types
-                    a_types = tuple(list(types) + list(optargs[:diff]))
-            elif num_args != num_types:
-                raise InvalidArguments(f'{name} takes exactly {num_types} arguments, but got {num_args}.')
-
-            for i, (arg, type_) in enumerate(itertools.zip_longest(args, a_types, fillvalue=varargs), start=1):
-                if not isinstance(arg, type_):
-                    if isinstance(type_, tuple):
-                        shouldbe = 'one of: {}'.format(", ".join(f'"{t.__name__}"' for t in type_))
-                    else:
-                        shouldbe = f'"{type_.__name__}"'
-                    raise InvalidArguments(f'{name} argument {i} was of type "{type(arg).__name__}" but should have been {shouldbe}')
-
-            # Ensure that we're actually passing a tuple.
-            # Depending on what kind of function we're calling the length of
-            # wrapped_args can vary.
-            nargs = list(wrapped_args)
-            i = nargs.index(args)
-            if varargs:
-                # if we have varargs we need to split them into a separate
-                # tuple, as python's typing doesn't understand tuples with
-                # fixed elements and variadic elements, only one or the other.
-                # so in that case we need T.Tuple[int, str, float, T.Tuple[str, ...]]
-                pos = args[:len(types)]
-                var = list(args[len(types):])
-                pos.append(var)
-                nargs[i] = tuple(pos)
-            elif optargs:
-                if num_args < num_types + len(optargs):
-                    diff =  num_types + len(optargs) - num_args
-                    nargs[i] = tuple(list(args) + [None] * diff)
-                else:
-                    nargs[i] = args
-            else:
-                nargs[i] = tuple(args)
-            return f(*nargs, **wrapped_kwargs)
-
-        return T.cast(TV_func, wrapper)
-    return inner
-
-
-class ContainerTypeInfo:
-
-    """Container information for keyword arguments.
-
-    For keyword arguments that are containers (list or dict), this class encodes
-    that information.
-
-    :param container: the type of container
-    :param contains: the types the container holds
-    :param pairs: if the container is supposed to be of even length.
-        This is mainly used for interfaces that predate the addition of dictionaries, and use
-        `[key, value, key2, value2]` format.
-    :param allow_empty: Whether this container is allowed to be empty
-        There are some cases where containers not only must be passed, but must
-        not be empty, and other cases where an empty container is allowed.
-    """
-
-    def __init__(self, container: T.Type, contains: T.Union[T.Type, T.Tuple[T.Type, ...]], *,
-                 pairs: bool = False, allow_empty: bool = True) :
-        self.container = container
-        self.contains = contains
-        self.pairs = pairs
-        self.allow_empty = allow_empty
-
-    def check(self, value: T.Any) -> T.Optional[str]:
-        """Check that a value is valid.
-
-        :param value: A value to check
-        :return: If there is an error then a string message, otherwise None
-        """
-        if not isinstance(value, self.container):
-            return f'container type was "{type(value).__name__}", but should have been "{self.container.__name__}"'
-        iter_ = iter(value.values()) if isinstance(value, dict) else iter(value)
-        for each in iter_:
-            if not isinstance(each, self.contains):
-                if isinstance(self.contains, tuple):
-                    shouldbe = 'one of: {}'.format(", ".join(f'"{t.__name__}"' for t in self.contains))
-                else:
-                    shouldbe = f'"{self.contains.__name__}"'
-                return f'contained a value of type "{type(each).__name__}" but should have been {shouldbe}'
-        if self.pairs and len(value) % 2 != 0:
-            return 'container should be of even length, but is not'
-        if not value and not self.allow_empty:
-            return 'container is empty, but not allowed to be'
-        return None
-
-
-_T = T.TypeVar('_T')
-
-
-class KwargInfo(T.Generic[_T]):
-
-    """A description of a keyword argument to a meson function
-
-    This is used to describe a value to the :func:typed_kwargs function.
-
-    :param name: the name of the parameter
-    :param types: A type or tuple of types that are allowed, or a :class:ContainerType
-    :param required: Whether this is a required keyword argument. defaults to False
-    :param listify: If true, then the argument will be listified before being
-        checked. This is useful for cases where the Meson DSL allows a scalar or
-        a container, but internally we only want to work with containers
-    :param default: A default value to use if this isn't set. defaults to None,
-        this may be safely set to a mutable type, as long as that type does not
-        itself contain mutable types, typed_kwargs will copy the default
-    :param since: Meson version in which this argument has been added. defaults to None
-    :param deprecated: Meson version in which this argument has been deprecated. defaults to None
-    :param validator: A callable that does additional validation. This is mainly
-        intended for cases where a string is expected, but only a few specific
-        values are accepted. Must return None if the input is valid, or a
-        message if the input is invalid
-    :param convertor: A callable that converts the raw input value into a
-        different type. This is intended for cases such as the meson DSL using a
-        string, but the implementation using an Enum. This should not do
-        validation, just converstion.
-    """
-
-    def __init__(self, name: str, types: T.Union[T.Type[_T], T.Tuple[T.Type[_T], ...], ContainerTypeInfo],
-                 *, required: bool = False, listify: bool = False,
-                 default: T.Optional[_T] = None,
-                 since: T.Optional[str] = None,
-                 deprecated: T.Optional[str] = None,
-                 validator: T.Optional[T.Callable[[_T], T.Optional[str]]] = None,
-                 convertor: T.Optional[T.Callable[[_T], TYPE_nvar]] = None):
-        self.name = name
-        self.types = types
-        self.required = required
-        self.listify = listify
-        self.default = default
-        self.since = since
-        self.deprecated = deprecated
-        self.validator = validator
-        self.convertor = convertor
-
-
-def typed_kwargs(name: str, *types: KwargInfo) -> T.Callable[..., T.Any]:
-    """Decorator for type checking keyword arguments.
-
-    Used to wrap a meson DSL implementation function, where it checks various
-    things about keyword arguments, including the type, and various other
-    information. For non-required values it sets the value to a default, which
-    means the value will always be provided.
-
-    If type tyhpe is a :class:ContainerTypeInfo, then the default value will be
-    passed as an argument to the container initializer, making a shallow copy
-
-    :param name: the name of the function, including the object it's attached ot
-        (if applicable)
-    :param *types: KwargInfo entries for each keyword argument.
-    """
-    def inner(f: TV_func) -> TV_func:
-
-        @wraps(f)
-        def wrapper(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            kwargs, subproject = get_callee_args(wrapped_args, want_subproject=True)[3:5]
-
-            all_names = {t.name for t in types}
-            unknowns = set(kwargs).difference(all_names)
-            if unknowns:
-                # Warn about unknown argumnts, delete them and continue. This
-                # keeps current behavior
-                ustr = ', '.join([f'"{u}"' for u in sorted(unknowns)])
-                mlog.warning(f'{name} got unknown keyword arguments {ustr}')
-                for u in unknowns:
-                    del kwargs[u]
-
-            for info in types:
-                value = kwargs.get(info.name)
-                if value is not None:
-                    if info.since:
-                        feature_name = info.name + ' arg in ' + name
-                        FeatureNew.single_use(feature_name, info.since, subproject)
-                    if info.deprecated:
-                        feature_name = info.name + ' arg in ' + name
-                        FeatureDeprecated.single_use(feature_name, info.deprecated, subproject)
-                    if info.listify:
-                        kwargs[info.name] = value = mesonlib.listify(value)
-                    if isinstance(info.types, ContainerTypeInfo):
-                        msg = info.types.check(value)
-                        if msg is not None:
-                            raise InvalidArguments(f'{name} keyword argument "{info.name}" {msg}')
-                    else:
-                        if not isinstance(value, info.types):
-                            if isinstance(info.types, tuple):
-                                shouldbe = 'one of: {}'.format(", ".join(f'"{t.__name__}"' for t in info.types))
-                            else:
-                                shouldbe = f'"{info.types.__name__}"'
-                            raise InvalidArguments(f'{name} keyword argument "{info.name}"" was of type "{type(value).__name__}" but should have been {shouldbe}')
-
-                    if info.validator is not None:
-                        msg = info.validator(value)
-                        if msg is not None:
-                            raise InvalidArguments(f'{name} keyword argument "{info.name}" {msg}')
-                elif info.required:
-                    raise InvalidArguments(f'{name} is missing required keyword argument "{info.name}"')
-                else:
-                    # set the value to the default, this ensuring all kwargs are present
-                    # This both simplifies the typing checking and the usage
-                    # Create a shallow copy of the container (and do a type
-                    # conversion if necessary). This allows mutable types to
-                    # be used safely as default values
-                    if isinstance(info.types, ContainerTypeInfo):
-                        kwargs[info.name] = info.types.container(info.default)
-                    else:
-                        kwargs[info.name] = info.default
-
-                if info.convertor:
-                    kwargs[info.name] = info.convertor(kwargs[info.name])
-
-            return f(*wrapped_args, **wrapped_kwargs)
-        return T.cast(TV_func, wrapper)
-    return inner
-
-
-class FeatureCheckBase(metaclass=abc.ABCMeta):
-    "Base class for feature version checks"
-
-    # In python 3.6 we can just forward declare this, but in 3.5 we can't
-    # This will be overwritten by the subclasses by necessity
-    feature_registry = {}  # type: T.ClassVar[T.Dict[str, T.Dict[str, T.Set[str]]]]
-
-    def __init__(self, feature_name: str, version: str, extra_message: T.Optional[str] = None):
-        self.feature_name = feature_name  # type: str
-        self.feature_version = version    # type: str
-        self.extra_message = extra_message or ''  # type: str
-
-    @staticmethod
-    def get_target_version(subproject: str) -> str:
-        # Don't do any checks if project() has not been parsed yet
-        if subproject not in mesonlib.project_meson_versions:
-            return ''
-        return mesonlib.project_meson_versions[subproject]
-
-    @staticmethod
-    @abc.abstractmethod
-    def check_version(target_version: str, feature_Version: str) -> bool:
-        pass
-
-    def use(self, subproject: str) -> None:
-        tv = self.get_target_version(subproject)
-        # No target version
-        if tv == '':
-            return
-        # Target version is new enough
-        if self.check_version(tv, self.feature_version):
-            return
-        # Feature is too new for target version, register it
-        if subproject not in self.feature_registry:
-            self.feature_registry[subproject] = {self.feature_version: set()}
-        register = self.feature_registry[subproject]
-        if self.feature_version not in register:
-            register[self.feature_version] = set()
-        if self.feature_name in register[self.feature_version]:
-            # Don't warn about the same feature multiple times
-            # FIXME: This is needed to prevent duplicate warnings, but also
-            # means we won't warn about a feature used in multiple places.
-            return
-        register[self.feature_version].add(self.feature_name)
-        self.log_usage_warning(tv)
-
-    @classmethod
-    def report(cls, subproject: str) -> None:
-        if subproject not in cls.feature_registry:
-            return
-        warning_str = cls.get_warning_str_prefix(cls.get_target_version(subproject))
-        fv = cls.feature_registry[subproject]
-        for version in sorted(fv.keys()):
-            warning_str += '\n * {}: {}'.format(version, fv[version])
-        mlog.warning(warning_str)
-
-    def log_usage_warning(self, tv: str) -> None:
-        raise InterpreterException('log_usage_warning not implemented')
-
-    @staticmethod
-    def get_warning_str_prefix(tv: str) -> str:
-        raise InterpreterException('get_warning_str_prefix not implemented')
-
-    def __call__(self, f: TV_func) -> TV_func:
-        @wraps(f)
-        def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            subproject = get_callee_args(wrapped_args, want_subproject=True)[4]
-            if subproject is None:
-                raise AssertionError(f'{wrapped_args!r}')
-            self.use(subproject)
-            return f(*wrapped_args, **wrapped_kwargs)
-        return T.cast(TV_func, wrapped)
-
-    @classmethod
-    def single_use(cls, feature_name: str, version: str, subproject: str,
-                   extra_message: T.Optional[str] = None) -> None:
-        """Oneline version that instantiates and calls use()."""
-        cls(feature_name, version, extra_message).use(subproject)
-
-
-class FeatureNew(FeatureCheckBase):
-    """Checks for new features"""
-
-    # Class variable, shared across all instances
-    #
-    # Format: {subproject: {feature_version: set(feature_names)}}
-    feature_registry = {}  # type: T.ClassVar[T.Dict[str, T.Dict[str, T.Set[str]]]]
-
-    @staticmethod
-    def check_version(target_version: str, feature_version: str) -> bool:
-        return mesonlib.version_compare_condition_with_min(target_version, feature_version)
-
-    @staticmethod
-    def get_warning_str_prefix(tv: str) -> str:
-        return f'Project specifies a minimum meson_version \'{tv}\' but uses features which were added in newer versions:'
-
-    def log_usage_warning(self, tv: str) -> None:
-        args = [
-            'Project targeting', f"'{tv}'",
-            'but tried to use feature introduced in',
-            f"'{self.feature_version}':",
-            f'{self.feature_name}.',
-        ]
-        if self.extra_message:
-            args.append(self.extra_message)
-        mlog.warning(*args)
-
-class FeatureDeprecated(FeatureCheckBase):
-    """Checks for deprecated features"""
-
-    # Class variable, shared across all instances
-    #
-    # Format: {subproject: {feature_version: set(feature_names)}}
-    feature_registry = {}  # type: T.ClassVar[T.Dict[str, T.Dict[str, T.Set[str]]]]
-
-    @staticmethod
-    def check_version(target_version: str, feature_version: str) -> bool:
-        # For deprecation checks we need to return the inverse of FeatureNew checks
-        return not mesonlib.version_compare_condition_with_min(target_version, feature_version)
-
-    @staticmethod
-    def get_warning_str_prefix(tv: str) -> str:
-        return 'Deprecated features used:'
-
-    def log_usage_warning(self, tv: str) -> None:
-        args = [
-            'Project targeting', f"'{tv}'",
-            'but tried to use feature deprecated since',
-            f"'{self.feature_version}':",
-            f'{self.feature_name}.',
-        ]
-        if self.extra_message:
-            args.append(self.extra_message)
-        mlog.warning(*args)
-
-
-class FeatureCheckKwargsBase(metaclass=abc.ABCMeta):
-
-    @property
-    @abc.abstractmethod
-    def feature_check_class(self) -> T.Type[FeatureCheckBase]:
-        pass
-
-    def __init__(self, feature_name: str, feature_version: str,
-                 kwargs: T.List[str], extra_message: T.Optional[str] = None):
-        self.feature_name = feature_name
-        self.feature_version = feature_version
-        self.kwargs = kwargs
-        self.extra_message = extra_message
-
-    def __call__(self, f: TV_func) -> TV_func:
-        @wraps(f)
-        def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            kwargs, subproject = get_callee_args(wrapped_args, want_subproject=True)[3:5]
-            if subproject is None:
-                raise AssertionError(f'{wrapped_args!r}')
-            for arg in self.kwargs:
-                if arg not in kwargs:
-                    continue
-                name = arg + ' arg in ' + self.feature_name
-                self.feature_check_class.single_use(
-                        name, self.feature_version, subproject, self.extra_message)
-            return f(*wrapped_args, **wrapped_kwargs)
-        return T.cast(TV_func, wrapped)
-
-class FeatureNewKwargs(FeatureCheckKwargsBase):
-    feature_check_class = FeatureNew
-
-class FeatureDeprecatedKwargs(FeatureCheckKwargsBase):
-    feature_check_class = FeatureDeprecated
-
 class InterpreterBase:
     elementary_types = (int, float, str, bool, list)