diff --git a/third_party/3/typed_ast/__init__.pyi b/third_party/3/typed_ast/__init__.pyi
new file mode 100644
index 000000000..92e1216b1
--- /dev/null
+++ b/third_party/3/typed_ast/__init__.pyi
@@ -0,0 +1,2 @@
+# This module is a fork of the CPython 2.7 and 3.5  ast modules with PEP 484 support.
+# See: https://github.com/dropbox/typed_ast
diff --git a/third_party/3/typed_ast/ast27.pyi b/third_party/3/typed_ast/ast27.pyi
new file mode 100644
index 000000000..a2f325253
--- /dev/null
+++ b/third_party/3/typed_ast/ast27.pyi
@@ -0,0 +1,365 @@
+import typing
+from typing import Any, Optional, Union, TypeVar, Generic, Iterator
+
+T = TypeVar("T")
+class NodeVisitor(Generic[T]):
+    __doc__ = ...  # type: str
+    def visit(self, node: AST) -> T: ...
+    def generic_visit(self, node: AST) -> None: ...
+
+class NodeTransformer(NodeVisitor, Generic[T]):
+    __doc__ = ...  # type: str
+    def generic_visit(self, node: AST) -> None: ...
+
+def parse(source: Union[str, bytes], filename: Union[str, bytes] = ..., mode: str = ...) -> AST: ...
+def copy_location(new_node: AST, old_node: AST) -> AST: ...
+def dump(node: AST, annotate_fields: bool = ..., include_attributes: bool = ...) -> str: ...
+def fix_missing_locations(node: AST) -> AST: ...
+def get_docstring(node: AST, clean: bool = ...) -> str: ...
+def increment_lineno(node: AST, n: int = ...) -> AST: ...
+def iter_child_nodes(node: AST) -> Iterator[AST]: ...
+def iter_fields(node: AST) -> Iterator[typing.Tuple[str, Any]]: ...
+def literal_eval(node_or_string: Union[str, AST]) -> Any: ...
+def walk(node: AST) -> Iterator[AST]: ...
+
+PyCF_ONLY_AST = ... # type: int
+
+# ast classes
+
+identifier = str
+
+class AST:
+    _attributes = ... # type: typing.Tuple[str, ...]
+    _fields = ... # type: typing.Tuple[str, ...]
+    def __init__(self, *args, **kwargs): ...
+    def __delattr__(self, name): ...
+    def __reduce__(self): ...
+    def __setattr__(self, name, value): ...
+
+class mod(AST):
+    pass
+
+class Module(mod):
+    body = ...  # type: typing.List[stmt]
+    type_ignores = ...  # type: typing.List[TypeIgnore]
+
+class Interactive(mod):
+    body = ...  # type: typing.List[stmt]
+
+class Expression(mod):
+    body = ...  # type: expr
+
+class FunctionType(mod):
+    argtypes = ...  # type: typing.List[expr]
+    returns = ...  # type: expr
+
+class Suite(mod):
+    body = ...  # type: typing.List[stmt]
+
+
+class stmt(AST):
+    lineno = ...  # type: int
+    col_offset = ...  # type: int
+
+class FunctionDef(stmt):
+    name = ...  # type: identifier
+    args = ...  # type: arguments
+    body = ...  # type: typing.List[stmt]
+    decorator_list = ...  # type: typing.List[expr]
+    type_comment = ...  # type: Optional[str]
+
+class ClassDef(stmt):
+    name = ...  # type: identifier
+    bases = ...  # type: typing.List[expr]
+    body = ...  # type: typing.List[stmt]
+    decorator_list = ...  # type: typing.List[expr]
+
+class Return(stmt):
+    value = ...  # type: Optional[expr]
+
+class Delete(stmt):
+    targets = ...  # type: typing.List[expr]
+
+class Assign(stmt):
+    targets = ...  # type: typing.List[expr]
+    value = ...  # type: expr
+    type_comment = ...  # type: Optional[str]
+
+class AugAssign(stmt):
+    target = ...  # type: expr
+    op = ...  # type: operator
+    value = ...  # type: expr
+
+class Print(stmt):
+    dest = ...  # type: Optional[expr]
+    values = ...  # type: typing.List[expr]
+    nl = ...  # type: bool
+
+class For(stmt):
+    target = ...  # type: expr
+    iter = ...  # type: expr
+    body = ...  # type: typing.List[stmt]
+    orelse = ...  # type: typing.List[stmt]
+    type_comment = ...  # type: Optional[str]
+
+class While(stmt):
+    test = ...  # type: expr
+    body = ...  # type: typing.List[stmt]
+    orelse = ...  # type: typing.List[stmt]
+
+class If(stmt):
+    test = ...  # type: expr
+    body = ...  # type: typing.List[stmt]
+    orelse = ...  # type: typing.List[stmt]
+
+class With(stmt):
+    context_expr = ...  # type: expr
+    optional_vars = ...  # type: Optional[expr]
+    body = ...  # type: typing.List[stmt]
+    type_comment = ...  # type: Optional[str]
+
+class Raise(stmt):
+    type = ...  # type: Optional[expr]
+    inst = ...  # type: Optional[expr]
+    tback = ...  # type: Optional[expr]
+
+class TryExcept(stmt):
+    body = ...  # type: typing.List[stmt]
+    handlers = ...  # type: typing.List[ExceptHandler]
+    orelse = ...  # type: typing.List[stmt]
+
+class TryFinally(stmt):
+    body = ...  # type: typing.List[stmt]
+    finalbody = ...  # type: typing.List[stmt]
+
+class Assert(stmt):
+    test = ...  # type: expr
+    msg = ...  # type: Optional[expr]
+
+class Import(stmt):
+    names = ...  # type: typing.List[alias]
+
+class ImportFrom(stmt):
+    module = ...  # type: Optional[identifier]
+    names = ...  # type: typing.List[alias]
+    level = ...  # type: Optional[int]
+
+class Exec(stmt):
+    body = ...  # type: expr
+    globals = ...  # type: Optional[expr]
+    locals = ...  # type: Optional[expr]
+
+class Global(stmt):
+    names = ...  # type: typing.List[identifier]
+
+class Expr(stmt):
+    value = ...  # type: expr
+
+class Pass(stmt): pass
+class Break(stmt): pass
+class Continue(stmt): pass
+
+
+class slice(AST):
+    pass
+
+_slice = slice  # this lets us type the variable named 'slice' below
+
+class Slice(slice):
+    lower = ...  # type: Optional[expr]
+    upper = ...  # type: Optional[expr]
+    step = ...  # type: Optional[expr]
+
+class ExtSlice(slice):
+    dims = ...  # type: typing.List[slice]
+
+class Index(slice):
+    value = ...  # type: expr
+
+class Ellipsis(slice): pass
+
+
+class expr(AST):
+    lineno = ...  # type: int
+    col_offset = ...  # type: int
+
+class BoolOp(expr):
+    op = ...  # type: boolop
+    values = ...  # type: typing.List[expr]
+
+class BinOp(expr):
+    left = ...  # type: expr
+    op = ...  # type: operator
+    right = ...  # type: expr
+
+class UnaryOp(expr):
+    op = ...  # type: unaryop
+    operand = ...  # type: expr
+
+class Lambda(expr):
+    args = ...  # type: arguments
+    body = ...  # type: expr
+
+class IfExp(expr):
+    test = ...  # type: expr
+    body = ...  # type: expr
+    orelse = ...  # type: expr
+
+class Dict(expr):
+    keys = ...  # type: typing.List[expr]
+    values = ...  # type: typing.List[expr]
+
+class Set(expr):
+    elts = ...  # type: typing.List[expr]
+
+class ListComp(expr):
+    elt = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class SetComp(expr):
+    elt = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class DictComp(expr):
+    key = ...  # type: expr
+    value = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class GeneratorExp(expr):
+    elt = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class Yield(expr):
+    value = ...  # type: Optional[expr]
+
+class Compare(expr):
+    left = ...  # type: expr
+    ops = ...  # type: typing.List[cmpop]
+    comparators = ...  # type: typing.List[expr]
+
+class Call(expr):
+    func = ...  # type: expr
+    args = ...  # type: typing.List[expr]
+    keywords = ...  # type: typing.List[keyword]
+    starargs = ...  # type: Optional[expr]
+    kwargs = ...  # type: Optional[expr]
+
+class Repr(expr):
+    value = ...  # type: expr
+
+class Num(expr):
+    n = ...  # type: Union[int, float]
+
+class Str(expr):
+    s = ...  # type: str
+
+class Attribute(expr):
+    value = ...  # type: expr
+    attr = ...  # type: identifier
+    ctx = ...  # type: expr_context
+
+class Subscript(expr):
+    value = ...  # type: expr
+    slice = ...  # type: _slice
+    ctx = ...  # type: expr_context
+
+class Name(expr):
+    id = ...  # type: identifier
+    ctx = ...  # type: expr_context
+
+class List(expr):
+    elts = ...  # type: typing.List[expr]
+    ctx = ...  # type: expr_context
+
+class Tuple(expr):
+    elts = ...  # type: typing.List[expr]
+    ctx = ...  # type: expr_context
+
+
+class expr_context(AST):
+    pass
+
+class AugLoad(expr_context): pass
+class AugStore(expr_context): pass
+class Del(expr_context): pass
+class Load(expr_context): pass
+class Param(expr_context): pass
+class Store(expr_context): pass
+
+
+class boolop(AST):
+    pass
+
+class And(boolop): pass
+class Or(boolop): pass
+
+class operator(AST):
+    pass
+
+class Add(operator): pass
+class BitAnd(operator): pass
+class BitOr(operator): pass
+class BitXor(operator): pass
+class Div(operator): pass
+class FloorDiv(operator): pass
+class LShift(operator): pass
+class Mod(operator): pass
+class Mult(operator): pass
+class Pow(operator): pass
+class RShift(operator): pass
+class Sub(operator): pass
+
+class unaryop(AST):
+    pass
+
+class Invert(unaryop): pass
+class Not(unaryop): pass
+class UAdd(unaryop): pass
+class USub(unaryop): pass
+
+class cmpop(AST):
+    pass
+
+class Eq(cmpop): pass
+class Gt(cmpop): pass
+class GtE(cmpop): pass
+class In(cmpop): pass
+class Is(cmpop): pass
+class IsNot(cmpop): pass
+class Lt(cmpop): pass
+class LtE(cmpop): pass
+class NotEq(cmpop): pass
+class NotIn(cmpop): pass
+
+
+class comprehension(AST):
+    target = ...  # type: expr
+    iter = ...  # type: expr
+    ifs = ...  # type: typing.List[expr]
+
+
+class ExceptHandler(AST):
+    type = ...  # type: Optional[expr]
+    name = ...  # type: Optional[expr]
+    body = ...  # type: typing.List[stmt]
+    lineno = ...  # type: int
+    col_offset = ...  # type: int
+
+
+class arguments(AST):
+    args = ...  # type: typing.List[expr]
+    vararg = ...  # type: Optional[identifier]
+    kwarg = ...  # type: Optional[identifier]
+    defaults = ...  # type: typing.List[expr]
+
+class keyword(AST):
+    arg = ...  # type: identifier
+    value = ...  # type: expr
+
+class alias(AST):
+    name = ...  # type: identifier
+    asname = ...  # type: Optional[identifier]
+
+
+class TypeIgnore(AST):
+    lineno = ...  # type: int
diff --git a/third_party/3/typed_ast/ast35.pyi b/third_party/3/typed_ast/ast35.pyi
new file mode 100644
index 000000000..7fdae0a77
--- /dev/null
+++ b/third_party/3/typed_ast/ast35.pyi
@@ -0,0 +1,397 @@
+import typing
+from typing import Any, Optional, Union, TypeVar, Generic, Iterator
+
+T = TypeVar("T")
+class NodeVisitor(Generic[T]):
+    __doc__ = ...  # type: str
+    def visit(self, node: AST) -> T: ...
+    def generic_visit(self, node: AST) -> None: ...
+
+class NodeTransformer(NodeVisitor, Generic[T]):
+    __doc__ = ...  # type: str
+    def generic_visit(self, node: AST) -> None: ...
+
+def parse(source: Union[str, bytes], filename: Union[str, bytes] = ..., mode: str = ...) -> AST: ...
+def copy_location(new_node: AST, old_node: AST) -> AST: ...
+def dump(node: AST, annotate_fields: bool = ..., include_attributes: bool = ...) -> str: ...
+def fix_missing_locations(node: AST) -> AST: ...
+def get_docstring(node: AST, clean: bool = ...) -> str: ...
+def increment_lineno(node: AST, n: int = ...) -> AST: ...
+def iter_child_nodes(node: AST) -> Iterator[AST]: ...
+def iter_fields(node: AST) -> Iterator[typing.Tuple[str, Any]]: ...
+def literal_eval(node_or_string: Union[str, AST]) -> Any: ...
+def walk(node: AST) -> Iterator[AST]: ...
+
+PyCF_ONLY_AST = ... # type: int
+
+# ast classes
+
+identifier = str
+
+class AST:
+    _attributes = ... # type: typing.Tuple[str, ...]
+    _fields = ... # type: typing.Tuple[str, ...]
+    def __init__(self, *args, **kwargs): ...
+    def __delattr__(self, name): ...
+    def __reduce__(self): ...
+    def __setattr__(self, name, value): ...
+
+class mod(AST):
+    pass
+
+class Module(mod):
+    body = ...  # type: typing.List[stmt]
+    type_ignores = ...  # type: typing.List[TypeIgnore]
+
+class Interactive(mod):
+    body = ...  # type: typing.List[stmt]
+
+class Expression(mod):
+    body = ...  # type: expr
+
+class FunctionType(mod):
+    argtypes = ...  # type: typing.List[expr]
+    returns = ...  # type: expr
+
+class Suite(mod):
+    body = ...  # type: typing.List[stmt]
+
+
+class stmt(AST):
+    lineno = ...  # type: int
+    col_offset = ...  # type: int
+
+class FunctionDef(stmt):
+    name = ...  # type: identifier
+    args = ...  # type: arguments
+    body = ...  # type: typing.List[stmt]
+    decorator_list = ...  # type: typing.List[expr]
+    returns = ...  # type: Optional[expr]
+    type_comment = ...  # type: Optional[str]
+
+class AsyncFunctionDef(stmt):
+    name = ...  # type: identifier
+    args = ...  # type: arguments
+    body = ...  # type: typing.List[stmt]
+    decorator_list = ...  # type: typing.List[expr]
+    returns = ...  # type: Optional[expr]
+    type_comment = ...  # type: Optional[str]
+
+class ClassDef(stmt):
+    name = ...  # type: identifier
+    bases = ...  # type: typing.List[expr]
+    keywords = ...  # type: typing.List[keyword]
+    body = ...  # type: typing.List[stmt]
+    decorator_list = ...  # type: typing.List[expr]
+
+class Return(stmt):
+    value = ...  # type: Optional[expr]
+
+class Delete(stmt):
+    targets = ...  # type: typing.List[expr]
+
+class Assign(stmt):
+    targets = ...  # type: typing.List[expr]
+    value = ...  # type: expr
+    type_comment = ...  # type: Optional[str]
+
+class AugAssign(stmt):
+    target = ...  # type: expr
+    op = ...  # type: operator
+    value = ...  # type: expr
+
+class For(stmt):
+    target = ...  # type: expr
+    iter = ...  # type: expr
+    body = ...  # type: typing.List[stmt]
+    orelse = ...  # type: typing.List[stmt]
+    type_comment = ...  # type: Optional[str]
+
+class AsyncFor(stmt):
+    target = ...  # type: expr
+    iter = ...  # type: expr
+    body = ...  # type: typing.List[stmt]
+    orelse = ...  # type: typing.List[stmt]
+
+class While(stmt):
+    test = ...  # type: expr
+    body = ...  # type: typing.List[stmt]
+    orelse = ...  # type: typing.List[stmt]
+
+class If(stmt):
+    test = ...  # type: expr
+    body = ...  # type: typing.List[stmt]
+    orelse = ...  # type: typing.List[stmt]
+
+class With(stmt):
+    items = ...  # type: typing.List[withitem]
+    body = ...  # type: typing.List[stmt]
+    type_comment = ...  # type: Optional[str]
+
+class AsyncWith(stmt):
+    items = ...  # type: typing.List[withitem]
+    body = ...  # type: typing.List[stmt]
+
+class Raise(stmt):
+    exc = ...  # type: Optional[expr]
+    cause = ...  # type: Optional[expr]
+
+class Try(stmt):
+    body = ...  # type: typing.List[stmt]
+    handlers = ...  # type: typing.List[ExceptHandler]
+    orelse = ...  # type: typing.List[stmt]
+    finalbody = ...  # type: typing.List[stmt]
+
+class Assert(stmt):
+    test = ...  # type: expr
+    msg = ...  # type: Optional[expr]
+
+class Import(stmt):
+    names = ...  # type: typing.List[alias]
+
+class ImportFrom(stmt):
+    module = ...  # type: Optional[identifier]
+    names = ...  # type: typing.List[alias]
+    level = ...  # type: Optional[int]
+
+class Global(stmt):
+    names = ...  # type: typing.List[identifier]
+
+class Nonlocal(stmt):
+    names = ...  # type: typing.List[identifier]
+
+class Expr(stmt):
+    value = ...  # type: expr
+
+class Pass(stmt): pass
+class Break(stmt): pass
+class Continue(stmt): pass
+
+
+class slice(AST):
+    pass
+
+_slice = slice  # this lets us type the variable named 'slice' below
+
+class Slice(slice):
+    lower = ...  # type: Optional[expr]
+    upper = ...  # type: Optional[expr]
+    step = ...  # type: Optional[expr]
+
+class ExtSlice(slice):
+    dims = ...  # type: typing.List[slice]
+
+class Index(slice):
+    value = ...  # type: expr
+
+
+class expr(AST):
+    lineno = ...  # type: int
+    col_offset = ...  # type: int
+
+class BoolOp(expr):
+    op = ...  # type: boolop
+    values = ...  # type: typing.List[expr]
+
+class BinOp(expr):
+    left = ...  # type: expr
+    op = ...  # type: operator
+    right = ...  # type: expr
+
+class UnaryOp(expr):
+    op = ...  # type: unaryop
+    operand = ...  # type: expr
+
+class Lambda(expr):
+    args = ...  # type: arguments
+    body = ...  # type: expr
+
+class IfExp(expr):
+    test = ...  # type: expr
+    body = ...  # type: expr
+    orelse = ...  # type: expr
+
+class Dict(expr):
+    keys = ...  # type: typing.List[expr]
+    values = ...  # type: typing.List[expr]
+
+class Set(expr):
+    elts = ...  # type: typing.List[expr]
+
+class ListComp(expr):
+    elt = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class SetComp(expr):
+    elt = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class DictComp(expr):
+    key = ...  # type: expr
+    value = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class GeneratorExp(expr):
+    elt = ...  # type: expr
+    generators = ...  # type: typing.List[comprehension]
+
+class Await(expr):
+    value = ...  # type: expr
+
+class Yield(expr):
+    value = ...  # type: Optional[expr]
+
+class YieldFrom(expr):
+    value = ...  # type: expr
+
+class Compare(expr):
+    left = ...  # type: expr
+    ops = ...  # type: typing.List[cmpop]
+    comparators = ...  # type: typing.List[expr]
+
+class Call(expr):
+    func = ...  # type: expr
+    args = ...  # type: typing.List[expr]
+    keywords = ...  # type: typing.List[keyword]
+
+class Num(expr):
+    n = ...  # type: Union[int, float]
+
+class Str(expr):
+    s = ...  # type: str
+
+class Bytes(expr):
+    s = ...  # type: bytes
+
+class NameConstant(expr):
+    value = ...  # type: Any
+
+class Ellipsis(expr): pass
+
+class Attribute(expr):
+    value = ...  # type: expr
+    attr = ...  # type: identifier
+    ctx = ...  # type: expr_context
+
+class Subscript(expr):
+    value = ...  # type: expr
+    slice = ...  # type: _slice
+    ctx = ...  # type: expr_context
+
+class Starred(expr):
+    value = ...  # type: expr
+    ctx = ...  # type: expr_context
+
+class Name(expr):
+    id = ...  # type: identifier
+    ctx = ...  # type: expr_context
+
+class List(expr):
+    elts = ...  # type: typing.List[expr]
+    ctx = ...  # type: expr_context
+
+class Tuple(expr):
+    elts = ...  # type: typing.List[expr]
+    ctx = ...  # type: expr_context
+
+
+class expr_context(AST):
+    pass
+
+class AugLoad(expr_context): pass
+class AugStore(expr_context): pass
+class Del(expr_context): pass
+class Load(expr_context): pass
+class Param(expr_context): pass
+class Store(expr_context): pass
+
+
+class boolop(AST):
+    pass
+
+class And(boolop): pass
+class Or(boolop): pass
+
+class operator(AST):
+    pass
+
+class Add(operator): pass
+class BitAnd(operator): pass
+class BitOr(operator): pass
+class BitXor(operator): pass
+class Div(operator): pass
+class FloorDiv(operator): pass
+class LShift(operator): pass
+class Mod(operator): pass
+class Mult(operator): pass
+class MatMult(operator): pass
+class Pow(operator): pass
+class RShift(operator): pass
+class Sub(operator): pass
+
+class unaryop(AST):
+    pass
+
+class Invert(unaryop): pass
+class Not(unaryop): pass
+class UAdd(unaryop): pass
+class USub(unaryop): pass
+
+class cmpop(AST):
+    pass
+
+class Eq(cmpop): pass
+class Gt(cmpop): pass
+class GtE(cmpop): pass
+class In(cmpop): pass
+class Is(cmpop): pass
+class IsNot(cmpop): pass
+class Lt(cmpop): pass
+class LtE(cmpop): pass
+class NotEq(cmpop): pass
+class NotIn(cmpop): pass
+
+
+class comprehension(AST):
+    target = ...  # type: expr
+    iter = ...  # type: expr
+    ifs = ...  # type: typing.List[expr]
+
+
+class ExceptHandler(AST):
+    type = ...  # type: Optional[expr]
+    name = ...  # type: Optional[identifier]
+    body = ...  # type: typing.List[stmt]
+    lineno = ...  # type: int
+    col_offset = ...  # type: int
+
+
+class arguments(AST):
+    args = ...  # type: typing.List[arg]
+    vararg = ...  # type: Optional[arg]
+    kwonlyargs = ...  # type: typing.List[arg]
+    kw_defaults = ...  # type: typing.List[expr]
+    kwarg = ...  # type: Optional[arg]
+    defaults = ...  # type: typing.List[expr]
+
+class arg(AST):
+    arg = ...  # type: identifier
+    annotation = ...  # type: Optional[expr]
+    lineno = ...  # type: int
+    col_offset = ...  # type: int
+
+class keyword(AST):
+    arg = ...  # type: Optional[identifier]
+    value = ...  # type: expr
+
+class alias(AST):
+    name = ...  # type: identifier
+    asname = ...  # type: Optional[identifier]
+
+class withitem(AST):
+    context_expr = ...  # type: expr
+    optional_vars = ...  # type: Optional[expr]
+
+
+class TypeIgnore(AST):
+    lineno = ...  # type: int
diff --git a/third_party/3/typed_ast/conversions.pyi b/third_party/3/typed_ast/conversions.pyi
new file mode 100644
index 000000000..53fcc3283
--- /dev/null
+++ b/third_party/3/typed_ast/conversions.pyi
@@ -0,0 +1,4 @@
+from . import ast27
+from . import ast35
+
+def py2to3(ast: ast27.AST) -> ast35.AST: ...