Merged revisions 62004 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r62004 | georg.brandl | 2008-03-28 13:11:56 +0100 (Fr, 28 Mär 2008) | 4 lines

  Patch #1810 by Thomas Lee, reviewed by myself:
  allow compiling Python AST objects into code objects
  in compile().
........

8 files changed, 3474 insertions, 51 deletions

diff --git a/Doc/library/_ast.rst b/Doc/library/_ast.rst
index 9f56156..518798e 100644
--- a/Doc/library/_ast.rst
+++ b/Doc/library/_ast.rst
@@ -10,16 +10,16 @@ Abstract Syntax Trees
 
 
 The ``_ast`` module helps Python applications to process trees of the Python
-abstract syntax grammar. The Python compiler currently provides read-only access
-to such trees, meaning that applications can only create a tree for a given
-piece of Python source code; generating :term:`bytecode` from a (potentially modified)
-tree is not supported. The abstract syntax itself might change with each Python
-release; this module helps to find out programmatically what the current grammar
-looks like.
+abstract syntax grammar.  The abstract syntax itself might change with each
+Python release; this module helps to find out programmatically what the current
+grammar looks like.
 
-An abstract syntax tree can be generated by passing ``_ast.PyCF_ONLY_AST`` as a
-flag to the :func:`compile` builtin function. The result will be a tree of
-objects whose classes all inherit from ``_ast.AST``.
+An abstract syntax tree can be generated by passing :data:`_ast.PyCF_ONLY_AST`
+as a flag to the :func:`compile` builtin function. The result will be a tree of
+objects whose classes all inherit from :class:`_ast.AST`.
+
+A modified abstract syntax tree can be compiled into a Python code object using
+the built-in :func:`compile` function.
 
 The actual classes are derived from the ``Parser/Python.asdl`` file, which is
 reproduced below. There is one class defined for each left-hand side symbol in
@@ -39,12 +39,15 @@ attribute ``left`` of type ``_ast.expr``.   Instances of ``_ast.expr`` and
 ``_ast.stmt`` subclasses also have lineno and col_offset attributes.  The lineno
 is the line number of source text (1 indexed so the first line is line 1) and
 the col_offset is the utf8 byte offset of the first token that generated the
-node.  The utf8 offset is recorded because the parser uses utf8  internally.
+node.  The utf8 offset is recorded because the parser uses utf8 internally.
 
 If these attributes are marked as optional in the grammar (using a question
 mark), the value might be ``None``. If the attributes can have zero-or-more
 values (marked with an asterisk), the values are represented as Python lists.
 
+The constructors of all ``_ast`` classes don't take arguments; instead, if you
+create instances, you must assign the required attributes separately.
+
 
 Abstract Grammar
 ----------------
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 7c97edb..d1e979c 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -193,21 +193,21 @@ available.  They are listed here in alphabetical order.
 
 .. function:: compile(source, filename, mode[, flags[, dont_inherit]])
 
-   Compile the *source* into a code object.  Code objects can be executed by a call
-   to :func:`exec` or evaluated by a call to :func:`eval`.  The *filename* argument
-   should give the file from which the code was read; pass some recognizable value
-   if it wasn't read from a file (``'<string>'`` is commonly used). The *mode*
-   argument specifies what kind of code must be compiled; it can be ``'exec'`` if
-   *source* consists of a sequence of statements, ``'eval'`` if it consists of a
-   single expression, or ``'single'`` if it consists of a single interactive
-   statement (in the latter case, expression statements that evaluate to something
-   else than ``None`` will be printed).
-
-   When compiling multi-line statements, two caveats apply: line endings must be
-   represented by a single newline character (``'\n'``), and the input must be
-   terminated by at least one newline character.  If line endings are represented
-   by ``'\r\n'``, use the string :meth:`replace` method to change them into
-   ``'\n'``.
+   Compile the *source* into a code object.  Code objects can be
+   executed by a call to :func:`exec` or evaluated by a call to
+   :func:`eval`. *source* can either be a string or an AST object.
+   Refer to the :mod:`_ast` module documentation for information on
+   how to compile into and from AST objects.
+
+   The *filename* argument should give the file from
+   which the code was read; pass some recognizable value if it wasn't
+   read from a file (``'<string>'`` is commonly used). The *mode*
+   argument specifies what kind of code must be compiled; it can be
+   ``'exec'`` if *source* consists of a sequence of statements,
+   ``'eval'`` if it consists of a single expression, or ``'single'``
+   if it consists of a single interactive statement (in the latter
+   case, expression statements that evaluate to something else than
+   ``None`` will be printed).
 
    The optional arguments *flags* and *dont_inherit* (which are new in Python 2.2)
    control which future statements (see :pep:`236`) affect the compilation of
@@ -227,6 +227,9 @@ available.  They are listed here in alphabetical order.
    This function raises :exc:`SyntaxError` if the compiled source is invalid,
    and :exc:`TypeError` if the source contains null bytes.
 
+   .. versionadded:: 2.6
+      Support for compiling AST objects.
+
 
 .. function:: complex([real[, imag]])
 
diff --git a/Include/Python-ast.h b/Include/Python-ast.h
index 51e5298..c018ddd 100644
--- a/Include/Python-ast.h
+++ b/Include/Python-ast.h
@@ -542,3 +542,5 @@ keyword_ty _Py_keyword(identifier arg, expr_ty value, PyArena *arena);
 alias_ty _Py_alias(identifier name, identifier asname, PyArena *arena);
 
 PyObject* PyAST_mod2obj(mod_ty t);
+mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena);
+int PyAST_Check(PyObject* obj);
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index 4979f92..376369b 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -1,5 +1,6 @@
 import unittest
 import sys
+import _ast
 from test import test_support
 
 class TestSpecifics(unittest.TestCase):
@@ -406,6 +407,28 @@ if 1:
         self.assert_("_A__mangled_mod" in A.f.__code__.co_varnames)
         self.assert_("__package__" in A.f.__code__.co_varnames)
 
+    def test_compile_ast(self):
+        fname = __file__
+        if fname.lower().endswith(('pyc', 'pyo')):
+            fname = fname[:-1]
+        with open(fname, 'r') as f:
+            fcontents = f.read()
+        sample_code = [
+            ['<assign>', 'x = 5'],
+            ['<ifblock>', """if True:\n    pass\n"""],
+            ['<forblock>', """for n in [1, 2, 3]:\n    print(n)\n"""],
+            ['<deffunc>', """def foo():\n    pass\nfoo()\n"""],
+            [fname, fcontents],
+        ]
+
+        for fname, code in sample_code:
+            co1 = compile(code, '%s1' % fname, 'exec')
+            ast = compile(code, '%s2' % fname, 'exec', _ast.PyCF_ONLY_AST)
+            self.assert_(type(ast) == _ast.Module)
+            co2 = compile(ast, '%s3' % fname, 'exec')
+            self.assertEqual(co1, co2)
+
+
 def test_main():
     test_support.run_unittest(TestSpecifics)
 
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index df4a91d..496ad01 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -73,12 +73,12 @@ def is_simple(sum):
     A sum is simple if its types have no fields, e.g.
     unaryop = Invert | Not | UAdd | USub
     """
-
     for t in sum.types:
         if t.fields:
             return False
     return True
 
+
 class EmitVisitor(asdl.VisitorBase):
     """Visit that emits lines"""
 
@@ -96,6 +96,7 @@ class EmitVisitor(asdl.VisitorBase):
             line = (" " * TABSIZE * depth) + line + "\n"
             self.file.write(line)
 
+
 class TypeDefVisitor(EmitVisitor):
     def visitModule(self, mod):
         for dfn in mod.dfns:
@@ -133,6 +134,7 @@ class TypeDefVisitor(EmitVisitor):
         self.emit(s, depth)
         self.emit("", depth)
 
+
 class StructVisitor(EmitVisitor):
     """Visitor to generate typdefs for AST."""
 
@@ -202,6 +204,7 @@ class StructVisitor(EmitVisitor):
         self.emit("};", depth)
         self.emit("", depth)
 
+
 class PrototypeVisitor(EmitVisitor):
     """Generate function prototypes for the .h file"""
 
@@ -271,6 +274,7 @@ class PrototypeVisitor(EmitVisitor):
         self.emit_function(name, get_c_type(name),
                            self.get_args(prod.fields), [], union=0)
 
+
 class FunctionVisitor(PrototypeVisitor):
     """Visitor to generate constructor functions for AST."""
 
@@ -324,6 +328,7 @@ class FunctionVisitor(PrototypeVisitor):
             emit("p->%s = %s;" % (argname, argname), 1)
         assert not attrs
 
+
 class PickleVisitor(EmitVisitor):
 
     def visitModule(self, mod):
@@ -345,6 +350,181 @@ class PickleVisitor(EmitVisitor):
     def visitField(self, sum):
         pass
 
+
+class Obj2ModPrototypeVisitor(PickleVisitor):
+    def visitProduct(self, prod, name):
+        code = "static int obj2ast_%s(PyObject* obj, %s* out, PyArena* arena);"
+        self.emit(code % (name, get_c_type(name)), 0)
+
+    visitSum = visitProduct
+
+
+class Obj2ModVisitor(PickleVisitor):
+    def funcHeader(self, name):
+        ctype = get_c_type(name)
+        self.emit("int", 0)
+        self.emit("obj2ast_%s(PyObject* obj, %s* out, PyArena* arena)" % (name, ctype), 0)
+        self.emit("{", 0)
+        self.emit("PyObject* tmp = NULL;", 1)
+        self.emit("", 0)
+
+    def sumTrailer(self, name):
+        self.emit("", 0)
+        self.emit("tmp = PyObject_Repr(obj);", 1)
+        # there's really nothing more we can do if this fails ...
+        self.emit("if (tmp == NULL) goto failed;", 1)
+        error = "expected some sort of %s, but got %%.400s" % name
+        format = "PyErr_Format(PyExc_TypeError, \"%s\", PyString_AS_STRING(tmp));"
+        self.emit(format % error, 1, reflow=False)
+        self.emit("failed:", 0)
+        self.emit("Py_XDECREF(tmp);", 1)
+        self.emit("return 1;", 1)
+        self.emit("}", 0)
+        self.emit("", 0)
+
+    def simpleSum(self, sum, name):
+        self.funcHeader(name)
+        for t in sum.types:
+            self.emit("if (PyObject_IsInstance(obj, (PyObject*)%s_type)) {" % t.name, 1)
+            self.emit("*out = %s;" % t.name, 2)
+            self.emit("return 0;", 2)
+            self.emit("}", 1)
+        self.sumTrailer(name)
+
+    def buildArgs(self, fields):
+        return ", ".join(fields + ["arena"])
+
+    def complexSum(self, sum, name):
+        self.funcHeader(name)
+        for a in sum.attributes:
+            self.visitAttributeDeclaration(a, name, sum=sum)
+        self.emit("", 0)
+        # XXX: should we only do this for 'expr'?
+        self.emit("if (obj == Py_None) {", 1)
+        self.emit("*out = NULL;", 2)
+        self.emit("return 0;", 2)
+        self.emit("}", 1)
+        for a in sum.attributes:
+            self.visitField(a, name, sum=sum, depth=1)
+        for t in sum.types:
+            self.emit("if (PyObject_IsInstance(obj, (PyObject*)%s_type)) {" % t.name, 1)
+            for f in t.fields:
+                self.visitFieldDeclaration(f, t.name, sum=sum, depth=2)
+            self.emit("", 0)
+            for f in t.fields:
+                self.visitField(f, t.name, sum=sum, depth=2)
+            args = [f.name.value for f in t.fields] + [a.name.value for a in sum.attributes]
+            self.emit("*out = %s(%s);" % (t.name, self.buildArgs(args)), 2)
+            self.emit("if (*out == NULL) goto failed;", 2)
+            self.emit("return 0;", 2)
+            self.emit("}", 1)
+        self.sumTrailer(name)
+
+    def visitAttributeDeclaration(self, a, name, sum=sum):
+        ctype = get_c_type(a.type)
+        self.emit("%s %s;" % (ctype, a.name), 1)
+
+    def visitSum(self, sum, name):
+        if is_simple(sum):
+            self.simpleSum(sum, name)
+        else:
+            self.complexSum(sum, name)
+
+    def visitProduct(self, prod, name):
+        ctype = get_c_type(name)
+        self.emit("int", 0)
+        self.emit("obj2ast_%s(PyObject* obj, %s* out, PyArena* arena)" % (name, ctype), 0)
+        self.emit("{", 0)
+        self.emit("PyObject* tmp = NULL;", 1)
+        for f in prod.fields:
+            self.visitFieldDeclaration(f, name, prod=prod, depth=1)
+        self.emit("", 0)
+        for f in prod.fields:
+            self.visitField(f, name, prod=prod, depth=1)
+        args = [f.name.value for f in prod.fields]
+        self.emit("*out = %s(%s);" % (name, self.buildArgs(args)), 1)
+        self.emit("return 0;", 1)
+        self.emit("failed:", 0)
+        self.emit("Py_XDECREF(tmp);", 1)
+        self.emit("return 1;", 1)
+        self.emit("}", 0)
+        self.emit("", 0)
+
+    def visitFieldDeclaration(self, field, name, sum=None, prod=None, depth=0):
+        ctype = get_c_type(field.type)
+        if field.seq:
+            if self.isSimpleType(field):
+                self.emit("asdl_int_seq* %s;" % field.name, depth)
+            else:
+                self.emit("asdl_seq* %s;" % field.name, depth)
+        else:
+            ctype = get_c_type(field.type)
+            self.emit("%s %s;" % (ctype, field.name), depth)
+
+    def isSimpleSum(self, field):
+        # XXX can the members of this list be determined automatically?
+        return field.type.value in ('expr_context', 'boolop', 'operator',
+                                    'unaryop', 'cmpop')
+
+    def isNumeric(self, field):
+        return get_c_type(field.type) in ("int", "bool")
+
+    def isSimpleType(self, field):
+        return self.isSimpleSum(field) or self.isNumeric(field)
+
+    def visitField(self, field, name, sum=None, prod=None, depth=0):
+        ctype = get_c_type(field.type)
+        self.emit("if (PyObject_HasAttrString(obj, \"%s\")) {" % field.name, depth)
+        self.emit("int res;", depth+1)
+        if field.seq:
+            self.emit("Py_ssize_t len;", depth+1)
+            self.emit("Py_ssize_t i;", depth+1)
+        self.emit("tmp = PyObject_GetAttrString(obj, \"%s\");" % field.name, depth+1)
+        self.emit("if (tmp == NULL) goto failed;", depth+1)
+        if field.seq:
+            self.emit("if (!PyList_Check(tmp)) {", depth+1)
+            self.emit("PyErr_Format(PyExc_TypeError, \"%s field \\\"%s\\\" must "
+                      "be a list, not a %%.200s\", tmp->ob_type->tp_name);" %
+                      (name, field.name),
+                      depth+2, reflow=False)
+            self.emit("goto failed;", depth+2)
+            self.emit("}", depth+1)
+            self.emit("len = PyList_GET_SIZE(tmp);", depth+1)
+            if self.isSimpleType(field):
+                self.emit("%s = asdl_int_seq_new(len, arena);" % field.name, depth+1)
+            else:
+                self.emit("%s = asdl_seq_new(len, arena);" % field.name, depth+1)
+            self.emit("if (%s == NULL) goto failed;" % field.name, depth+1)
+            self.emit("for (i = 0; i < len; i++) {", depth+1)
+            self.emit("%s value;" % ctype, depth+2)
+            self.emit("res = obj2ast_%s(PyList_GET_ITEM(tmp, i), &value, arena);" %
+                      field.type, depth+2, reflow=False)
+            self.emit("if (res != 0) goto failed;", depth+2)
+            self.emit("asdl_seq_SET(%s, i, value);" % field.name, depth+2)
+            self.emit("}", depth+1)
+        else:
+            self.emit("res = obj2ast_%s(tmp, &%s, arena);" %
+                      (field.type, field.name), depth+1)
+            self.emit("if (res != 0) goto failed;", depth+1)
+
+        self.emit("Py_XDECREF(tmp);", depth+1)
+        self.emit("tmp = NULL;", depth+1)
+        self.emit("} else {", depth)
+        if not field.opt:
+            message = "required field \\\"%s\\\" missing from %s" % (field.name, name)
+            format = "PyErr_SetString(PyExc_TypeError, \"%s\");"
+            self.emit(format % message, depth+1, reflow=False)
+            self.emit("return 1;", depth+1)
+        else:
+            if self.isNumeric(field):
+                self.emit("%s = 0;" % field.name, depth+1)
+            elif not self.isSimpleType(field):
+                self.emit("%s = NULL;" % field.name, depth+1)
+            else:
+                raise TypeError("could not determine the default value for %s" % field.name)
+        self.emit("}", depth)
+
+
 class MarshalPrototypeVisitor(PickleVisitor):
 
     def prototype(self, sum, name):
@@ -354,6 +534,7 @@ class MarshalPrototypeVisitor(PickleVisitor):
 
     visitProduct = visitSum = prototype
 
+
 class PyTypesDeclareVisitor(PickleVisitor):
 
     def visitProduct(self, prod, name):
@@ -439,6 +620,8 @@ static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
     return result;
 }
 
+/* Conversion AST -> Python */
+
 static PyObject* ast2obj_list(asdl_seq *seq, PyObject* (*func)(void*))
 {
     int i, n = asdl_seq_LEN(seq);
@@ -471,6 +654,42 @@ static PyObject* ast2obj_int(long b)
 {
     return PyLong_FromLong(b);
 }
+
+/* Conversion Python -> AST */
+
+static int obj2ast_object(PyObject* obj, PyObject** out, PyArena* arena)
+{
+    if (obj == Py_None)
+        obj = NULL;
+    if (obj)
+        PyArena_AddPyObject(arena, obj);
+    Py_XINCREF(obj);
+    *out = obj;
+    return 0;
+}
+
+#define obj2ast_identifier obj2ast_object
+#define obj2ast_string obj2ast_object
+
+static int obj2ast_int(PyObject* obj, int* out, PyArena* arena)
+{
+    int i;
+    if (!PyLong_Check(obj)) {
+        PyObject *s = PyObject_Repr(obj);
+        if (s == NULL) return 1;
+        PyErr_Format(PyExc_ValueError, "invalid integer value: %.400s",
+                     PyString_AS_STRING(s));
+        Py_DECREF(s);
+        return 1;
+    }
+
+    i = (int)PyLong_AsLong(obj);
+    if (i == -1 && PyErr_Occurred())
+        return 1;
+    *out = i;
+    return 0;
+}
+
 """, 0, reflow=False)
 
         self.emit("static int init_types(void)",0)
@@ -518,6 +737,7 @@ static PyObject* ast2obj_int(long b)
                              (cons.name, cons.name), 1)
             self.emit("if (!%s_singleton) return 0;" % cons.name, 1)
 
+
 def parse_version(mod):
     return mod.version.value[12:-3]
 
@@ -557,6 +777,7 @@ class ASTModuleVisitor(PickleVisitor):
     def addObj(self, name):
         self.emit('if (PyDict_SetItemString(d, "%s", (PyObject*)%s_type) < 0) return;' % (name, name), 1)
 
+
 _SPECIALIZED_SEQUENCES = ('stmt', 'expr')
 
 def find_sequence(fields, doing_specialization):
@@ -582,6 +803,7 @@ class StaticVisitor(PickleVisitor):
     def visit(self, object):
         self.emit(self.CODE, 0, reflow=False)
 
+
 class ObjVisitor(PickleVisitor):
 
     def func_begin(self, name):
@@ -632,8 +854,12 @@ class ObjVisitor(PickleVisitor):
             self.emit("case %s:" % t.name, 2)
             self.emit("Py_INCREF(%s_singleton);" % t.name, 3)
             self.emit("return %s_singleton;" % t.name, 3)
+        self.emit("default:" % name, 2)
+        self.emit('/* should never happen, but just in case ... */', 3)
+        code = "PyErr_Format(PyExc_SystemError, \"unknown %s found\");" % name
+        self.emit(code, 3, reflow=False)
+        self.emit("return NULL;", 3)
         self.emit("}", 1)
-        self.emit("return NULL; /* cannot happen */", 1)
         self.emit("}", 0)
 
     def visitProduct(self, prod, name):
@@ -707,6 +933,27 @@ PyObject* PyAST_mod2obj(mod_ty t)
     init_types();
     return ast2obj_mod(t);
 }
+
+mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena)
+{
+    mod_ty res;
+    init_types();
+    if (!PyObject_IsInstance(ast, mod_type)) {
+        PyErr_SetString(PyExc_TypeError, "expected either Module, Interactive "
+                        "or Expression node");
+        return NULL;
+    }
+    if (obj2ast_mod(ast, &res, arena) != 0)
+        return NULL;
+    else
+        return res;
+}
+
+int PyAST_Check(PyObject* obj)
+{
+    init_types();
+    return PyObject_IsInstance(obj, (PyObject*)AST_type);
+}
 """
 
 class ChainOfVisitors:
@@ -750,6 +997,8 @@ def main(srcfile):
                             )
         c.visit(mod)
         f.write("PyObject* PyAST_mod2obj(mod_ty t);\n")
+        print >>f, "mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena);"
+        print >>f, "int PyAST_Check(PyObject* obj);"
         f.close()
 
     if SRC_DIR:
@@ -764,8 +1013,10 @@ def main(srcfile):
         v = ChainOfVisitors(
             PyTypesDeclareVisitor(f),
             PyTypesVisitor(f),
+            Obj2ModPrototypeVisitor(f),
             FunctionVisitor(f),
             ObjVisitor(f),
+            Obj2ModVisitor(f),
             ASTModuleVisitor(f),
             PartingShots(f),
             )
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index c46176c..e89c9d5 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -434,6 +434,8 @@ static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
     return result;
 }
 
+/* Conversion AST -> Python */
+
 static PyObject* ast2obj_list(asdl_seq *seq, PyObject* (*func)(void*))
 {
     int i, n = asdl_seq_LEN(seq);
@@ -467,6 +469,42 @@ static PyObject* ast2obj_int(long b)
     return PyLong_FromLong(b);
 }
 
+/* Conversion Python -> AST */
+
+static int obj2ast_object(PyObject* obj, PyObject** out, PyArena* arena)
+{
+    if (obj == Py_None)
+        obj = NULL;
+    if (obj)
+        PyArena_AddPyObject(arena, obj);
+    Py_XINCREF(obj);
+    *out = obj;
+    return 0;
+}
+
+#define obj2ast_identifier obj2ast_object
+#define obj2ast_string obj2ast_object
+
+static int obj2ast_int(PyObject* obj, int* out, PyArena* arena)
+{
+    int i;
+    if (!PyLong_Check(obj)) {
+        PyObject *s = PyObject_Repr(obj);
+        if (s == NULL) return 1;
+        PyErr_Format(PyExc_ValueError, "invalid integer value: %.400s",
+                     PyString_AS_STRING(s));
+        Py_DECREF(s);
+        return 1;
+    }
+
+    i = (int)PyLong_AsLong(obj);
+    if (i == -1 && PyErr_Occurred())
+        return 1;
+    *out = i;
+    return 0;
+}
+
+
 static int init_types(void)
 {
         static int initialized;
@@ -765,6 +803,25 @@ static int init_types(void)
         return 1;
 }
 
+static int obj2ast_mod(PyObject* obj, mod_ty* out, PyArena* arena);
+static int obj2ast_stmt(PyObject* obj, stmt_ty* out, PyArena* arena);
+static int obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena);
+static int obj2ast_expr_context(PyObject* obj, expr_context_ty* out, PyArena*
+                                arena);
+static int obj2ast_slice(PyObject* obj, slice_ty* out, PyArena* arena);
+static int obj2ast_boolop(PyObject* obj, boolop_ty* out, PyArena* arena);
+static int obj2ast_operator(PyObject* obj, operator_ty* out, PyArena* arena);
+static int obj2ast_unaryop(PyObject* obj, unaryop_ty* out, PyArena* arena);
+static int obj2ast_cmpop(PyObject* obj, cmpop_ty* out, PyArena* arena);
+static int obj2ast_comprehension(PyObject* obj, comprehension_ty* out, PyArena*
+                                 arena);
+static int obj2ast_excepthandler(PyObject* obj, excepthandler_ty* out, PyArena*
+                                 arena);
+static int obj2ast_arguments(PyObject* obj, arguments_ty* out, PyArena* arena);
+static int obj2ast_arg(PyObject* obj, arg_ty* out, PyArena* arena);
+static int obj2ast_keyword(PyObject* obj, keyword_ty* out, PyArena* arena);
+static int obj2ast_alias(PyObject* obj, alias_ty* out, PyArena* arena);
+
 mod_ty
 Module(asdl_seq * body, PyArena *arena)
 {
@@ -2768,8 +2825,11 @@ PyObject* ast2obj_expr_context(expr_context_ty o)
                 case Param:
                         Py_INCREF(Param_singleton);
                         return Param_singleton;
+                default:
+                        /* should never happen, but just in case ... */
+                        PyErr_Format(PyExc_SystemError, "unknown expr_context found");
+                        return NULL;
         }
-        return NULL; /* cannot happen */
 }
 PyObject*
 ast2obj_slice(void* _o)
@@ -2836,8 +2896,11 @@ PyObject* ast2obj_boolop(boolop_ty o)
                 case Or:
                         Py_INCREF(Or_singleton);
                         return Or_singleton;
+                default:
+                        /* should never happen, but just in case ... */
+                        PyErr_Format(PyExc_SystemError, "unknown boolop found");
+                        return NULL;
         }
-        return NULL; /* cannot happen */
 }
 PyObject* ast2obj_operator(operator_ty o)
 {
@@ -2878,8 +2941,11 @@ PyObject* ast2obj_operator(operator_ty o)
                 case FloorDiv:
                         Py_INCREF(FloorDiv_singleton);
                         return FloorDiv_singleton;
+                default:
+                        /* should never happen, but just in case ... */
+                        PyErr_Format(PyExc_SystemError, "unknown operator found");
+                        return NULL;
         }
-        return NULL; /* cannot happen */
 }
 PyObject* ast2obj_unaryop(unaryop_ty o)
 {
@@ -2896,8 +2962,11 @@ PyObject* ast2obj_unaryop(unaryop_ty o)
                 case USub:
                         Py_INCREF(USub_singleton);
                         return USub_singleton;
+                default:
+                        /* should never happen, but just in case ... */
+                        PyErr_Format(PyExc_SystemError, "unknown unaryop found");
+                        return NULL;
         }
-        return NULL; /* cannot happen */
 }
 PyObject* ast2obj_cmpop(cmpop_ty o)
 {
@@ -2932,8 +3001,11 @@ PyObject* ast2obj_cmpop(cmpop_ty o)
                 case NotIn:
                         Py_INCREF(NotIn_singleton);
                         return NotIn_singleton;
+                default:
+                        /* should never happen, but just in case ... */
+                        PyErr_Format(PyExc_SystemError, "unknown cmpop found");
+                        return NULL;
         }
-        return NULL; /* cannot happen */
 }
 PyObject*
 ast2obj_comprehension(void* _o)
@@ -3160,6 +3232,3019 @@ failed:
 }
 
 
+int
+obj2ast_mod(PyObject* obj, mod_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+
+        if (obj == Py_None) {
+                *out = NULL;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Module_type)) {
+                asdl_seq* body;
+
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Module field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from Module");
+                        return 1;
+                }
+                *out = Module(body, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Interactive_type)) {
+                asdl_seq* body;
+
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Interactive field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from Interactive");
+                        return 1;
+                }
+                *out = Interactive(body, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Expression_type)) {
+                expr_ty body;
+
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &body, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from Expression");
+                        return 1;
+                }
+                *out = Expression(body, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Suite_type)) {
+                asdl_seq* body;
+
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Suite field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from Suite");
+                        return 1;
+                }
+                *out = Suite(body, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of mod, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_stmt(PyObject* obj, stmt_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+        int lineno;
+        int col_offset;
+
+        if (obj == Py_None) {
+                *out = NULL;
+                return 0;
+        }
+        if (PyObject_HasAttrString(obj, "lineno")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "lineno");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_int(tmp, &lineno, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"lineno\" missing from stmt");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "col_offset")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "col_offset");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_int(tmp, &col_offset, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"col_offset\" missing from stmt");
+                return 1;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)FunctionDef_type)) {
+                identifier name;
+                arguments_ty args;
+                asdl_seq* body;
+                asdl_seq* decorator_list;
+                expr_ty returns;
+
+                if (PyObject_HasAttrString(obj, "name")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "name");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_identifier(tmp, &name, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"name\" missing from FunctionDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "args")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "args");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_arguments(tmp, &args, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"args\" missing from FunctionDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "FunctionDef field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from FunctionDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "decorator_list")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "decorator_list");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "FunctionDef field \"decorator_list\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        decorator_list = asdl_seq_new(len, arena);
+                        if (decorator_list == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(decorator_list, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"decorator_list\" missing from FunctionDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "returns")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "returns");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &returns, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        returns = NULL;
+                }
+                *out = FunctionDef(name, args, body, decorator_list, returns,
+                                   lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)ClassDef_type)) {
+                identifier name;
+                asdl_seq* bases;
+                asdl_seq* keywords;
+                expr_ty starargs;
+                expr_ty kwargs;
+                asdl_seq* body;
+                asdl_seq* decorator_list;
+
+                if (PyObject_HasAttrString(obj, "name")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "name");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_identifier(tmp, &name, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"name\" missing from ClassDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "bases")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "bases");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "ClassDef field \"bases\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        bases = asdl_seq_new(len, arena);
+                        if (bases == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(bases, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"bases\" missing from ClassDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "keywords")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "keywords");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "ClassDef field \"keywords\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        keywords = asdl_seq_new(len, arena);
+                        if (keywords == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                keyword_ty value;
+                                res = obj2ast_keyword(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(keywords, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"keywords\" missing from ClassDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "starargs")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "starargs");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &starargs, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        starargs = NULL;
+                }
+                if (PyObject_HasAttrString(obj, "kwargs")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "kwargs");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &kwargs, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        kwargs = NULL;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "ClassDef field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from ClassDef");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "decorator_list")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "decorator_list");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "ClassDef field \"decorator_list\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        decorator_list = asdl_seq_new(len, arena);
+                        if (decorator_list == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(decorator_list, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"decorator_list\" missing from ClassDef");
+                        return 1;
+                }
+                *out = ClassDef(name, bases, keywords, starargs, kwargs, body,
+                                decorator_list, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Return_type)) {
+                expr_ty value;
+
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        value = NULL;
+                }
+                *out = Return(value, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Delete_type)) {
+                asdl_seq* targets;
+
+                if (PyObject_HasAttrString(obj, "targets")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "targets");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Delete field \"targets\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        targets = asdl_seq_new(len, arena);
+                        if (targets == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(targets, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"targets\" missing from Delete");
+                        return 1;
+                }
+                *out = Delete(targets, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Assign_type)) {
+                asdl_seq* targets;
+                expr_ty value;
+
+                if (PyObject_HasAttrString(obj, "targets")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "targets");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Assign field \"targets\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        targets = asdl_seq_new(len, arena);
+                        if (targets == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(targets, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"targets\" missing from Assign");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from Assign");
+                        return 1;
+                }
+                *out = Assign(targets, value, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)AugAssign_type)) {
+                expr_ty target;
+                operator_ty op;
+                expr_ty value;
+
+                if (PyObject_HasAttrString(obj, "target")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "target");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &target, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"target\" missing from AugAssign");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "op")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "op");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_operator(tmp, &op, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"op\" missing from AugAssign");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from AugAssign");
+                        return 1;
+                }
+                *out = AugAssign(target, op, value, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)For_type)) {
+                expr_ty target;
+                expr_ty iter;
+                asdl_seq* body;
+                asdl_seq* orelse;
+
+                if (PyObject_HasAttrString(obj, "target")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "target");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &target, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"target\" missing from For");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "iter")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "iter");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &iter, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"iter\" missing from For");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "For field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from For");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "orelse")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "orelse");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "For field \"orelse\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        orelse = asdl_seq_new(len, arena);
+                        if (orelse == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(orelse, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"orelse\" missing from For");
+                        return 1;
+                }
+                *out = For(target, iter, body, orelse, lineno, col_offset,
+                           arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)While_type)) {
+                expr_ty test;
+                asdl_seq* body;
+                asdl_seq* orelse;
+
+                if (PyObject_HasAttrString(obj, "test")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "test");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &test, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"test\" missing from While");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "While field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from While");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "orelse")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "orelse");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "While field \"orelse\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        orelse = asdl_seq_new(len, arena);
+                        if (orelse == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(orelse, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"orelse\" missing from While");
+                        return 1;
+                }
+                *out = While(test, body, orelse, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)If_type)) {
+                expr_ty test;
+                asdl_seq* body;
+                asdl_seq* orelse;
+
+                if (PyObject_HasAttrString(obj, "test")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "test");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &test, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"test\" missing from If");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "If field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from If");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "orelse")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "orelse");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "If field \"orelse\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        orelse = asdl_seq_new(len, arena);
+                        if (orelse == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(orelse, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"orelse\" missing from If");
+                        return 1;
+                }
+                *out = If(test, body, orelse, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)With_type)) {
+                expr_ty context_expr;
+                expr_ty optional_vars;
+                asdl_seq* body;
+
+                if (PyObject_HasAttrString(obj, "context_expr")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "context_expr");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &context_expr, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"context_expr\" missing from With");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "optional_vars")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "optional_vars");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &optional_vars, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        optional_vars = NULL;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "With field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from With");
+                        return 1;
+                }
+                *out = With(context_expr, optional_vars, body, lineno,
+                            col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Raise_type)) {
+                expr_ty exc;
+                expr_ty cause;
+
+                if (PyObject_HasAttrString(obj, "exc")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "exc");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &exc, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        exc = NULL;
+                }
+                if (PyObject_HasAttrString(obj, "cause")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "cause");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &cause, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        cause = NULL;
+                }
+                *out = Raise(exc, cause, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)TryExcept_type)) {
+                asdl_seq* body;
+                asdl_seq* handlers;
+                asdl_seq* orelse;
+
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "TryExcept field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from TryExcept");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "handlers")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "handlers");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "TryExcept field \"handlers\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        handlers = asdl_seq_new(len, arena);
+                        if (handlers == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                excepthandler_ty value;
+                                res = obj2ast_excepthandler(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(handlers, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"handlers\" missing from TryExcept");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "orelse")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "orelse");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "TryExcept field \"orelse\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        orelse = asdl_seq_new(len, arena);
+                        if (orelse == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(orelse, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"orelse\" missing from TryExcept");
+                        return 1;
+                }
+                *out = TryExcept(body, handlers, orelse, lineno, col_offset,
+                                 arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)TryFinally_type)) {
+                asdl_seq* body;
+                asdl_seq* finalbody;
+
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "TryFinally field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        body = asdl_seq_new(len, arena);
+                        if (body == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(body, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from TryFinally");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "finalbody")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "finalbody");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "TryFinally field \"finalbody\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        finalbody = asdl_seq_new(len, arena);
+                        if (finalbody == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                stmt_ty value;
+                                res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(finalbody, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"finalbody\" missing from TryFinally");
+                        return 1;
+                }
+                *out = TryFinally(body, finalbody, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Assert_type)) {
+                expr_ty test;
+                expr_ty msg;
+
+                if (PyObject_HasAttrString(obj, "test")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "test");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &test, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"test\" missing from Assert");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "msg")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "msg");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &msg, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        msg = NULL;
+                }
+                *out = Assert(test, msg, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Import_type)) {
+                asdl_seq* names;
+
+                if (PyObject_HasAttrString(obj, "names")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "names");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Import field \"names\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        names = asdl_seq_new(len, arena);
+                        if (names == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                alias_ty value;
+                                res = obj2ast_alias(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(names, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"names\" missing from Import");
+                        return 1;
+                }
+                *out = Import(names, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)ImportFrom_type)) {
+                identifier module;
+                asdl_seq* names;
+                int level;
+
+                if (PyObject_HasAttrString(obj, "module")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "module");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_identifier(tmp, &module, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"module\" missing from ImportFrom");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "names")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "names");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "ImportFrom field \"names\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        names = asdl_seq_new(len, arena);
+                        if (names == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                alias_ty value;
+                                res = obj2ast_alias(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(names, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"names\" missing from ImportFrom");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "level")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "level");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_int(tmp, &level, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        level = 0;
+                }
+                *out = ImportFrom(module, names, level, lineno, col_offset,
+                                  arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Global_type)) {
+                asdl_seq* names;
+
+                if (PyObject_HasAttrString(obj, "names")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "names");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Global field \"names\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        names = asdl_seq_new(len, arena);
+                        if (names == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                identifier value;
+                                res = obj2ast_identifier(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(names, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"names\" missing from Global");
+                        return 1;
+                }
+                *out = Global(names, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Nonlocal_type)) {
+                asdl_seq* names;
+
+                if (PyObject_HasAttrString(obj, "names")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "names");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Nonlocal field \"names\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        names = asdl_seq_new(len, arena);
+                        if (names == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                identifier value;
+                                res = obj2ast_identifier(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(names, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"names\" missing from Nonlocal");
+                        return 1;
+                }
+                *out = Nonlocal(names, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Expr_type)) {
+                expr_ty value;
+
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from Expr");
+                        return 1;
+                }
+                *out = Expr(value, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Pass_type)) {
+
+                *out = Pass(lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Break_type)) {
+
+                *out = Break(lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Continue_type)) {
+
+                *out = Continue(lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of stmt, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_expr(PyObject* obj, expr_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+        int lineno;
+        int col_offset;
+
+        if (obj == Py_None) {
+                *out = NULL;
+                return 0;
+        }
+        if (PyObject_HasAttrString(obj, "lineno")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "lineno");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_int(tmp, &lineno, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"lineno\" missing from expr");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "col_offset")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "col_offset");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_int(tmp, &col_offset, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"col_offset\" missing from expr");
+                return 1;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)BoolOp_type)) {
+                boolop_ty op;
+                asdl_seq* values;
+
+                if (PyObject_HasAttrString(obj, "op")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "op");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_boolop(tmp, &op, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"op\" missing from BoolOp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "values")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "values");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "BoolOp field \"values\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        values = asdl_seq_new(len, arena);
+                        if (values == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(values, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"values\" missing from BoolOp");
+                        return 1;
+                }
+                *out = BoolOp(op, values, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)BinOp_type)) {
+                expr_ty left;
+                operator_ty op;
+                expr_ty right;
+
+                if (PyObject_HasAttrString(obj, "left")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "left");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &left, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"left\" missing from BinOp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "op")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "op");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_operator(tmp, &op, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"op\" missing from BinOp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "right")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "right");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &right, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"right\" missing from BinOp");
+                        return 1;
+                }
+                *out = BinOp(left, op, right, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)UnaryOp_type)) {
+                unaryop_ty op;
+                expr_ty operand;
+
+                if (PyObject_HasAttrString(obj, "op")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "op");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_unaryop(tmp, &op, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"op\" missing from UnaryOp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "operand")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "operand");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &operand, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"operand\" missing from UnaryOp");
+                        return 1;
+                }
+                *out = UnaryOp(op, operand, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Lambda_type)) {
+                arguments_ty args;
+                expr_ty body;
+
+                if (PyObject_HasAttrString(obj, "args")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "args");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_arguments(tmp, &args, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"args\" missing from Lambda");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &body, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from Lambda");
+                        return 1;
+                }
+                *out = Lambda(args, body, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)IfExp_type)) {
+                expr_ty test;
+                expr_ty body;
+                expr_ty orelse;
+
+                if (PyObject_HasAttrString(obj, "test")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "test");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &test, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"test\" missing from IfExp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "body")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "body");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &body, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from IfExp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "orelse")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "orelse");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &orelse, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"orelse\" missing from IfExp");
+                        return 1;
+                }
+                *out = IfExp(test, body, orelse, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Dict_type)) {
+                asdl_seq* keys;
+                asdl_seq* values;
+
+                if (PyObject_HasAttrString(obj, "keys")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "keys");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Dict field \"keys\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        keys = asdl_seq_new(len, arena);
+                        if (keys == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(keys, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"keys\" missing from Dict");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "values")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "values");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Dict field \"values\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        values = asdl_seq_new(len, arena);
+                        if (values == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(values, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"values\" missing from Dict");
+                        return 1;
+                }
+                *out = Dict(keys, values, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Set_type)) {
+                asdl_seq* elts;
+
+                if (PyObject_HasAttrString(obj, "elts")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "elts");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Set field \"elts\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        elts = asdl_seq_new(len, arena);
+                        if (elts == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(elts, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elts\" missing from Set");
+                        return 1;
+                }
+                *out = Set(elts, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)ListComp_type)) {
+                expr_ty elt;
+                asdl_seq* generators;
+
+                if (PyObject_HasAttrString(obj, "elt")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "elt");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &elt, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elt\" missing from ListComp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "generators")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "generators");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "ListComp field \"generators\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        generators = asdl_seq_new(len, arena);
+                        if (generators == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                comprehension_ty value;
+                                res = obj2ast_comprehension(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(generators, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"generators\" missing from ListComp");
+                        return 1;
+                }
+                *out = ListComp(elt, generators, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)SetComp_type)) {
+                expr_ty elt;
+                asdl_seq* generators;
+
+                if (PyObject_HasAttrString(obj, "elt")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "elt");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &elt, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elt\" missing from SetComp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "generators")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "generators");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "SetComp field \"generators\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        generators = asdl_seq_new(len, arena);
+                        if (generators == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                comprehension_ty value;
+                                res = obj2ast_comprehension(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(generators, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"generators\" missing from SetComp");
+                        return 1;
+                }
+                *out = SetComp(elt, generators, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)DictComp_type)) {
+                expr_ty key;
+                expr_ty value;
+                asdl_seq* generators;
+
+                if (PyObject_HasAttrString(obj, "key")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "key");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &key, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"key\" missing from DictComp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from DictComp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "generators")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "generators");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "DictComp field \"generators\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        generators = asdl_seq_new(len, arena);
+                        if (generators == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                comprehension_ty value;
+                                res = obj2ast_comprehension(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(generators, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"generators\" missing from DictComp");
+                        return 1;
+                }
+                *out = DictComp(key, value, generators, lineno, col_offset,
+                                arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)GeneratorExp_type)) {
+                expr_ty elt;
+                asdl_seq* generators;
+
+                if (PyObject_HasAttrString(obj, "elt")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "elt");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &elt, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elt\" missing from GeneratorExp");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "generators")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "generators");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "GeneratorExp field \"generators\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        generators = asdl_seq_new(len, arena);
+                        if (generators == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                comprehension_ty value;
+                                res = obj2ast_comprehension(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(generators, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"generators\" missing from GeneratorExp");
+                        return 1;
+                }
+                *out = GeneratorExp(elt, generators, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Yield_type)) {
+                expr_ty value;
+
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        value = NULL;
+                }
+                *out = Yield(value, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Compare_type)) {
+                expr_ty left;
+                asdl_int_seq* ops;
+                asdl_seq* comparators;
+
+                if (PyObject_HasAttrString(obj, "left")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "left");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &left, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"left\" missing from Compare");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "ops")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "ops");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Compare field \"ops\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        ops = asdl_int_seq_new(len, arena);
+                        if (ops == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                cmpop_ty value;
+                                res = obj2ast_cmpop(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(ops, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"ops\" missing from Compare");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "comparators")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "comparators");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Compare field \"comparators\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        comparators = asdl_seq_new(len, arena);
+                        if (comparators == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(comparators, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"comparators\" missing from Compare");
+                        return 1;
+                }
+                *out = Compare(left, ops, comparators, lineno, col_offset,
+                               arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Call_type)) {
+                expr_ty func;
+                asdl_seq* args;
+                asdl_seq* keywords;
+                expr_ty starargs;
+                expr_ty kwargs;
+
+                if (PyObject_HasAttrString(obj, "func")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "func");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &func, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"func\" missing from Call");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "args")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "args");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Call field \"args\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        args = asdl_seq_new(len, arena);
+                        if (args == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(args, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"args\" missing from Call");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "keywords")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "keywords");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Call field \"keywords\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        keywords = asdl_seq_new(len, arena);
+                        if (keywords == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                keyword_ty value;
+                                res = obj2ast_keyword(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(keywords, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"keywords\" missing from Call");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "starargs")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "starargs");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &starargs, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        starargs = NULL;
+                }
+                if (PyObject_HasAttrString(obj, "kwargs")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "kwargs");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &kwargs, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        kwargs = NULL;
+                }
+                *out = Call(func, args, keywords, starargs, kwargs, lineno,
+                            col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Num_type)) {
+                object n;
+
+                if (PyObject_HasAttrString(obj, "n")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "n");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_object(tmp, &n, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"n\" missing from Num");
+                        return 1;
+                }
+                *out = Num(n, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Str_type)) {
+                string s;
+
+                if (PyObject_HasAttrString(obj, "s")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "s");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_string(tmp, &s, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"s\" missing from Str");
+                        return 1;
+                }
+                *out = Str(s, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Bytes_type)) {
+                string s;
+
+                if (PyObject_HasAttrString(obj, "s")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "s");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_string(tmp, &s, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"s\" missing from Bytes");
+                        return 1;
+                }
+                *out = Bytes(s, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Ellipsis_type)) {
+
+                *out = Ellipsis(lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Attribute_type)) {
+                expr_ty value;
+                identifier attr;
+                expr_context_ty ctx;
+
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from Attribute");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "attr")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "attr");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_identifier(tmp, &attr, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"attr\" missing from Attribute");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "ctx")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "ctx");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr_context(tmp, &ctx, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"ctx\" missing from Attribute");
+                        return 1;
+                }
+                *out = Attribute(value, attr, ctx, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Subscript_type)) {
+                expr_ty value;
+                slice_ty slice;
+                expr_context_ty ctx;
+
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from Subscript");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "slice")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "slice");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_slice(tmp, &slice, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"slice\" missing from Subscript");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "ctx")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "ctx");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr_context(tmp, &ctx, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"ctx\" missing from Subscript");
+                        return 1;
+                }
+                *out = Subscript(value, slice, ctx, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Starred_type)) {
+                expr_ty value;
+                expr_context_ty ctx;
+
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from Starred");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "ctx")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "ctx");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr_context(tmp, &ctx, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"ctx\" missing from Starred");
+                        return 1;
+                }
+                *out = Starred(value, ctx, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Name_type)) {
+                identifier id;
+                expr_context_ty ctx;
+
+                if (PyObject_HasAttrString(obj, "id")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "id");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_identifier(tmp, &id, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"id\" missing from Name");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "ctx")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "ctx");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr_context(tmp, &ctx, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"ctx\" missing from Name");
+                        return 1;
+                }
+                *out = Name(id, ctx, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)List_type)) {
+                asdl_seq* elts;
+                expr_context_ty ctx;
+
+                if (PyObject_HasAttrString(obj, "elts")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "elts");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "List field \"elts\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        elts = asdl_seq_new(len, arena);
+                        if (elts == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(elts, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elts\" missing from List");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "ctx")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "ctx");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr_context(tmp, &ctx, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"ctx\" missing from List");
+                        return 1;
+                }
+                *out = List(elts, ctx, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Tuple_type)) {
+                asdl_seq* elts;
+                expr_context_ty ctx;
+
+                if (PyObject_HasAttrString(obj, "elts")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "elts");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "Tuple field \"elts\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        elts = asdl_seq_new(len, arena);
+                        if (elts == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                expr_ty value;
+                                res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(elts, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"elts\" missing from Tuple");
+                        return 1;
+                }
+                if (PyObject_HasAttrString(obj, "ctx")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "ctx");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr_context(tmp, &ctx, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"ctx\" missing from Tuple");
+                        return 1;
+                }
+                *out = Tuple(elts, ctx, lineno, col_offset, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of expr, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_expr_context(PyObject* obj, expr_context_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+        if (PyObject_IsInstance(obj, (PyObject*)Load_type)) {
+                *out = Load;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Store_type)) {
+                *out = Store;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Del_type)) {
+                *out = Del;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)AugLoad_type)) {
+                *out = AugLoad;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)AugStore_type)) {
+                *out = AugStore;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Param_type)) {
+                *out = Param;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of expr_context, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_slice(PyObject* obj, slice_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+
+        if (obj == Py_None) {
+                *out = NULL;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Slice_type)) {
+                expr_ty lower;
+                expr_ty upper;
+                expr_ty step;
+
+                if (PyObject_HasAttrString(obj, "lower")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "lower");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &lower, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        lower = NULL;
+                }
+                if (PyObject_HasAttrString(obj, "upper")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "upper");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &upper, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        upper = NULL;
+                }
+                if (PyObject_HasAttrString(obj, "step")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "step");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &step, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        step = NULL;
+                }
+                *out = Slice(lower, upper, step, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)ExtSlice_type)) {
+                asdl_seq* dims;
+
+                if (PyObject_HasAttrString(obj, "dims")) {
+                        int res;
+                        Py_ssize_t len;
+                        Py_ssize_t i;
+                        tmp = PyObject_GetAttrString(obj, "dims");
+                        if (tmp == NULL) goto failed;
+                        if (!PyList_Check(tmp)) {
+                                PyErr_Format(PyExc_TypeError, "ExtSlice field \"dims\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                                goto failed;
+                        }
+                        len = PyList_GET_SIZE(tmp);
+                        dims = asdl_seq_new(len, arena);
+                        if (dims == NULL) goto failed;
+                        for (i = 0; i < len; i++) {
+                                slice_ty value;
+                                res = obj2ast_slice(PyList_GET_ITEM(tmp, i), &value, arena);
+                                if (res != 0) goto failed;
+                                asdl_seq_SET(dims, i, value);
+                        }
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"dims\" missing from ExtSlice");
+                        return 1;
+                }
+                *out = ExtSlice(dims, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Index_type)) {
+                expr_ty value;
+
+                if (PyObject_HasAttrString(obj, "value")) {
+                        int res;
+                        tmp = PyObject_GetAttrString(obj, "value");
+                        if (tmp == NULL) goto failed;
+                        res = obj2ast_expr(tmp, &value, arena);
+                        if (res != 0) goto failed;
+                        Py_XDECREF(tmp);
+                        tmp = NULL;
+                } else {
+                        PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from Index");
+                        return 1;
+                }
+                *out = Index(value, arena);
+                if (*out == NULL) goto failed;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of slice, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_boolop(PyObject* obj, boolop_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+        if (PyObject_IsInstance(obj, (PyObject*)And_type)) {
+                *out = And;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Or_type)) {
+                *out = Or;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of boolop, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_operator(PyObject* obj, operator_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+        if (PyObject_IsInstance(obj, (PyObject*)Add_type)) {
+                *out = Add;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Sub_type)) {
+                *out = Sub;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Mult_type)) {
+                *out = Mult;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Div_type)) {
+                *out = Div;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Mod_type)) {
+                *out = Mod;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Pow_type)) {
+                *out = Pow;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)LShift_type)) {
+                *out = LShift;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)RShift_type)) {
+                *out = RShift;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)BitOr_type)) {
+                *out = BitOr;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)BitXor_type)) {
+                *out = BitXor;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)BitAnd_type)) {
+                *out = BitAnd;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)FloorDiv_type)) {
+                *out = FloorDiv;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of operator, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_unaryop(PyObject* obj, unaryop_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+        if (PyObject_IsInstance(obj, (PyObject*)Invert_type)) {
+                *out = Invert;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Not_type)) {
+                *out = Not;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)UAdd_type)) {
+                *out = UAdd;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)USub_type)) {
+                *out = USub;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of unaryop, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_cmpop(PyObject* obj, cmpop_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+
+        if (PyObject_IsInstance(obj, (PyObject*)Eq_type)) {
+                *out = Eq;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)NotEq_type)) {
+                *out = NotEq;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Lt_type)) {
+                *out = Lt;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)LtE_type)) {
+                *out = LtE;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Gt_type)) {
+                *out = Gt;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)GtE_type)) {
+                *out = GtE;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)Is_type)) {
+                *out = Is;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)IsNot_type)) {
+                *out = IsNot;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)In_type)) {
+                *out = In;
+                return 0;
+        }
+        if (PyObject_IsInstance(obj, (PyObject*)NotIn_type)) {
+                *out = NotIn;
+                return 0;
+        }
+
+        tmp = PyObject_Repr(obj);
+        if (tmp == NULL) goto failed;
+        PyErr_Format(PyExc_TypeError, "expected some sort of cmpop, but got %.400s", PyString_AS_STRING(tmp));
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_comprehension(PyObject* obj, comprehension_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+        expr_ty target;
+        expr_ty iter;
+        asdl_seq* ifs;
+
+        if (PyObject_HasAttrString(obj, "target")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "target");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_expr(tmp, &target, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"target\" missing from comprehension");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "iter")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "iter");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_expr(tmp, &iter, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"iter\" missing from comprehension");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "ifs")) {
+                int res;
+                Py_ssize_t len;
+                Py_ssize_t i;
+                tmp = PyObject_GetAttrString(obj, "ifs");
+                if (tmp == NULL) goto failed;
+                if (!PyList_Check(tmp)) {
+                        PyErr_Format(PyExc_TypeError, "comprehension field \"ifs\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                        goto failed;
+                }
+                len = PyList_GET_SIZE(tmp);
+                ifs = asdl_seq_new(len, arena);
+                if (ifs == NULL) goto failed;
+                for (i = 0; i < len; i++) {
+                        expr_ty value;
+                        res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                        if (res != 0) goto failed;
+                        asdl_seq_SET(ifs, i, value);
+                }
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"ifs\" missing from comprehension");
+                return 1;
+        }
+        *out = comprehension(target, iter, ifs, arena);
+        return 0;
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_excepthandler(PyObject* obj, excepthandler_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+        expr_ty type;
+        identifier name;
+        asdl_seq* body;
+        int lineno;
+        int col_offset;
+
+        if (PyObject_HasAttrString(obj, "type")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "type");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_expr(tmp, &type, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                type = NULL;
+        }
+        if (PyObject_HasAttrString(obj, "name")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "name");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_identifier(tmp, &name, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                name = NULL;
+        }
+        if (PyObject_HasAttrString(obj, "body")) {
+                int res;
+                Py_ssize_t len;
+                Py_ssize_t i;
+                tmp = PyObject_GetAttrString(obj, "body");
+                if (tmp == NULL) goto failed;
+                if (!PyList_Check(tmp)) {
+                        PyErr_Format(PyExc_TypeError, "excepthandler field \"body\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                        goto failed;
+                }
+                len = PyList_GET_SIZE(tmp);
+                body = asdl_seq_new(len, arena);
+                if (body == NULL) goto failed;
+                for (i = 0; i < len; i++) {
+                        stmt_ty value;
+                        res = obj2ast_stmt(PyList_GET_ITEM(tmp, i), &value, arena);
+                        if (res != 0) goto failed;
+                        asdl_seq_SET(body, i, value);
+                }
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from excepthandler");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "lineno")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "lineno");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_int(tmp, &lineno, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"lineno\" missing from excepthandler");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "col_offset")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "col_offset");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_int(tmp, &col_offset, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"col_offset\" missing from excepthandler");
+                return 1;
+        }
+        *out = excepthandler(type, name, body, lineno, col_offset, arena);
+        return 0;
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_arguments(PyObject* obj, arguments_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+        asdl_seq* args;
+        identifier vararg;
+        expr_ty varargannotation;
+        asdl_seq* kwonlyargs;
+        identifier kwarg;
+        expr_ty kwargannotation;
+        asdl_seq* defaults;
+        asdl_seq* kw_defaults;
+
+        if (PyObject_HasAttrString(obj, "args")) {
+                int res;
+                Py_ssize_t len;
+                Py_ssize_t i;
+                tmp = PyObject_GetAttrString(obj, "args");
+                if (tmp == NULL) goto failed;
+                if (!PyList_Check(tmp)) {
+                        PyErr_Format(PyExc_TypeError, "arguments field \"args\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                        goto failed;
+                }
+                len = PyList_GET_SIZE(tmp);
+                args = asdl_seq_new(len, arena);
+                if (args == NULL) goto failed;
+                for (i = 0; i < len; i++) {
+                        arg_ty value;
+                        res = obj2ast_arg(PyList_GET_ITEM(tmp, i), &value, arena);
+                        if (res != 0) goto failed;
+                        asdl_seq_SET(args, i, value);
+                }
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"args\" missing from arguments");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "vararg")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "vararg");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_identifier(tmp, &vararg, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                vararg = NULL;
+        }
+        if (PyObject_HasAttrString(obj, "varargannotation")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "varargannotation");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_expr(tmp, &varargannotation, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                varargannotation = NULL;
+        }
+        if (PyObject_HasAttrString(obj, "kwonlyargs")) {
+                int res;
+                Py_ssize_t len;
+                Py_ssize_t i;
+                tmp = PyObject_GetAttrString(obj, "kwonlyargs");
+                if (tmp == NULL) goto failed;
+                if (!PyList_Check(tmp)) {
+                        PyErr_Format(PyExc_TypeError, "arguments field \"kwonlyargs\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                        goto failed;
+                }
+                len = PyList_GET_SIZE(tmp);
+                kwonlyargs = asdl_seq_new(len, arena);
+                if (kwonlyargs == NULL) goto failed;
+                for (i = 0; i < len; i++) {
+                        arg_ty value;
+                        res = obj2ast_arg(PyList_GET_ITEM(tmp, i), &value, arena);
+                        if (res != 0) goto failed;
+                        asdl_seq_SET(kwonlyargs, i, value);
+                }
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"kwonlyargs\" missing from arguments");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "kwarg")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "kwarg");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_identifier(tmp, &kwarg, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                kwarg = NULL;
+        }
+        if (PyObject_HasAttrString(obj, "kwargannotation")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "kwargannotation");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_expr(tmp, &kwargannotation, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                kwargannotation = NULL;
+        }
+        if (PyObject_HasAttrString(obj, "defaults")) {
+                int res;
+                Py_ssize_t len;
+                Py_ssize_t i;
+                tmp = PyObject_GetAttrString(obj, "defaults");
+                if (tmp == NULL) goto failed;
+                if (!PyList_Check(tmp)) {
+                        PyErr_Format(PyExc_TypeError, "arguments field \"defaults\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                        goto failed;
+                }
+                len = PyList_GET_SIZE(tmp);
+                defaults = asdl_seq_new(len, arena);
+                if (defaults == NULL) goto failed;
+                for (i = 0; i < len; i++) {
+                        expr_ty value;
+                        res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                        if (res != 0) goto failed;
+                        asdl_seq_SET(defaults, i, value);
+                }
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"defaults\" missing from arguments");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "kw_defaults")) {
+                int res;
+                Py_ssize_t len;
+                Py_ssize_t i;
+                tmp = PyObject_GetAttrString(obj, "kw_defaults");
+                if (tmp == NULL) goto failed;
+                if (!PyList_Check(tmp)) {
+                        PyErr_Format(PyExc_TypeError, "arguments field \"kw_defaults\" must be a list, not a %.200s", tmp->ob_type->tp_name);
+                        goto failed;
+                }
+                len = PyList_GET_SIZE(tmp);
+                kw_defaults = asdl_seq_new(len, arena);
+                if (kw_defaults == NULL) goto failed;
+                for (i = 0; i < len; i++) {
+                        expr_ty value;
+                        res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
+                        if (res != 0) goto failed;
+                        asdl_seq_SET(kw_defaults, i, value);
+                }
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"kw_defaults\" missing from arguments");
+                return 1;
+        }
+        *out = arguments(args, vararg, varargannotation, kwonlyargs, kwarg,
+                         kwargannotation, defaults, kw_defaults, arena);
+        return 0;
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_arg(PyObject* obj, arg_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+        identifier arg;
+        expr_ty annotation;
+
+        if (PyObject_HasAttrString(obj, "arg")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "arg");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_identifier(tmp, &arg, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"arg\" missing from arg");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "annotation")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "annotation");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_expr(tmp, &annotation, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                annotation = NULL;
+        }
+        *out = arg(arg, annotation, arena);
+        return 0;
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_keyword(PyObject* obj, keyword_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+        identifier arg;
+        expr_ty value;
+
+        if (PyObject_HasAttrString(obj, "arg")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "arg");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_identifier(tmp, &arg, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"arg\" missing from keyword");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "value")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "value");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_expr(tmp, &value, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from keyword");
+                return 1;
+        }
+        *out = keyword(arg, value, arena);
+        return 0;
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+int
+obj2ast_alias(PyObject* obj, alias_ty* out, PyArena* arena)
+{
+        PyObject* tmp = NULL;
+        identifier name;
+        identifier asname;
+
+        if (PyObject_HasAttrString(obj, "name")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "name");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_identifier(tmp, &name, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                PyErr_SetString(PyExc_TypeError, "required field \"name\" missing from alias");
+                return 1;
+        }
+        if (PyObject_HasAttrString(obj, "asname")) {
+                int res;
+                tmp = PyObject_GetAttrString(obj, "asname");
+                if (tmp == NULL) goto failed;
+                res = obj2ast_identifier(tmp, &asname, arena);
+                if (res != 0) goto failed;
+                Py_XDECREF(tmp);
+                tmp = NULL;
+        } else {
+                asname = NULL;
+        }
+        *out = alias(name, asname, arena);
+        return 0;
+failed:
+        Py_XDECREF(tmp);
+        return 1;
+}
+
+
 PyMODINIT_FUNC
 init_ast(void)
 {
@@ -3330,4 +6415,25 @@ PyObject* PyAST_mod2obj(mod_ty t)
     return ast2obj_mod(t);
 }
 
+mod_ty PyAST_obj2mod(PyObject* ast, PyArena* arena)
+{
+    mod_ty res;
+    init_types();
+    if (!PyObject_IsInstance(ast, mod_type)) {
+        PyErr_SetString(PyExc_TypeError, "expected either Module, Interactive "
+                        "or Expression node");
+        return NULL;
+    }
+    if (obj2ast_mod(ast, &res, arena) != 0)
+        return NULL;
+    else
+        return res;
+}
+
+int PyAST_Check(PyObject* obj)
+{
+    init_types();
+    return PyObject_IsInstance(obj, (PyObject*)AST_type);
+}
+
 
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index b3d8b16..ccfce06 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -1,6 +1,7 @@
 /* Built-in functions */
 
 #include "Python.h"
+#include "Python-ast.h"
 
 #include "node.h"
 #include "code.h"
@@ -527,10 +528,43 @@ builtin_compile(PyObject *self, PyObject *args, PyObject *kwds)
 
 	cf.cf_flags = supplied_flags | PyCF_SOURCE_IS_UTF8;
 
-	str = source_as_string(cmd);
-	if (str == NULL)
+	if (supplied_flags &
+	    ~(PyCF_MASK | PyCF_MASK_OBSOLETE | PyCF_DONT_IMPLY_DEDENT | PyCF_ONLY_AST))
+	{
+		PyErr_SetString(PyExc_ValueError,
+				"compile(): unrecognised flags");
 		return NULL;
+	}
+	/* XXX Warn if (supplied_flags & PyCF_MASK_OBSOLETE) != 0? */
 
+	if (!dont_inherit) {
+		PyEval_MergeCompilerFlags(&cf);
+	}
+
+	if (PyAST_Check(cmd)) {
+		PyObject *result;
+		if (supplied_flags & PyCF_ONLY_AST) {
+			Py_INCREF(cmd);
+			result = cmd;
+		}
+		else {
+			PyArena *arena;
+			mod_ty mod;
+
+			arena = PyArena_New();
+			mod = PyAST_obj2mod(cmd, arena);
+			if (mod == NULL) {
+				PyArena_Free(arena);
+				return NULL;
+			}
+			result = (PyObject*)PyAST_Compile(mod, filename,
+							  &cf, arena);
+			PyArena_Free(arena);
+		}
+		return result;
+	}
+
+	/* XXX: is it possible to pass start to the PyAST_ branch? */
 	if (strcmp(startstr, "exec") == 0)
 		start = Py_file_input;
 	else if (strcmp(startstr, "eval") == 0)
@@ -539,22 +573,15 @@ builtin_compile(PyObject *self, PyObject *args, PyObject *kwds)
 		start = Py_single_input;
 	else {
 		PyErr_SetString(PyExc_ValueError,
-		   "compile() arg 3 must be 'exec' or 'eval' or 'single'");
+				"compile() arg 3 must be 'exec'"
+				"or 'eval' or 'single'");
 		return NULL;
 	}
 
-	if (supplied_flags &
-	    ~(PyCF_MASK | PyCF_MASK_OBSOLETE | PyCF_DONT_IMPLY_DEDENT | PyCF_ONLY_AST))
-	{
-		PyErr_SetString(PyExc_ValueError,
-				"compile(): unrecognised flags");
+	str = source_as_string(cmd);
+	if (str == NULL)
 		return NULL;
-	}
-	/* XXX Warn if (supplied_flags & PyCF_MASK_OBSOLETE) != 0? */
 
-	if (!dont_inherit) {
-		PyEval_MergeCompilerFlags(&cf);
-	}
 	return Py_CompileStringFlags(str, filename, start, &cf);
 }
 
diff --git a/Python/compile.c b/Python/compile.c
index 7d5ada6..ab51c7b 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -2356,8 +2356,11 @@ unaryop(unaryop_ty op)
 		return UNARY_POSITIVE;
 	case USub:
 		return UNARY_NEGATIVE;
+	default:
+		PyErr_Format(PyExc_SystemError,
+			"unary op %d should not be possible", op);
+		return 0;
 	}
-	return 0;
 }
 
 static int
@@ -2388,8 +2391,11 @@ binop(struct compiler *c, operator_ty op)
 		return BINARY_AND;
 	case FloorDiv:
 		return BINARY_FLOOR_DIVIDE;
+	default:
+		PyErr_Format(PyExc_SystemError,
+			"binary op %d should not be possible", op);
+		return 0;
 	}
-	return 0;
 }
 
 static int
@@ -2416,8 +2422,9 @@ cmpop(cmpop_ty op)
 		return PyCmp_IN;
 	case NotIn:
 		return PyCmp_NOT_IN;
+	default:
+		return PyCmp_BAD;
 	}
-	return PyCmp_BAD;
 }
 
 static int
@@ -2448,10 +2455,11 @@ inplace_binop(struct compiler *c, operator_ty op)
 		return INPLACE_AND;
 	case FloorDiv:
 		return INPLACE_FLOOR_DIVIDE;
+	default:
+		PyErr_Format(PyExc_SystemError,
+			"inplace binary op %d should not be possible", op);
+		return 0;
 	}
-	PyErr_Format(PyExc_SystemError,
-		     "inplace binary op %d should not be possible", op);
-	return 0;
 }
 
 static int