diff --git a/python/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java b/python/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java
index 933cfb918ce9..8328310eae53 100644
--- a/python/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java
+++ b/python/src/com/jetbrains/python/codeInsight/stdlib/PyStdlibTypeProvider.java
@@ -136,6 +136,7 @@ public class PyStdlibTypeProvider extends PyTypeProviderBase {
       rtype = getReturnTypeByQName(overloadedQName, anchor);
       if (rtype != null) {
         boolean matched = true;
+        boolean notNullParameterMatch = false;
         for (Map.Entry<PyExpression, PyNamedParameter> entry : arguments.entrySet()) {
           final PyNamedParameter p = entry.getValue();
           final String name = p.getName();
@@ -144,7 +145,7 @@ public class PyStdlibTypeProvider extends PyTypeProviderBase {
           }
           PyType argType = entry.getKey().getType(context);
           // Special case for the 'mode' argument of the 'open()' builtin
-          if (("__builtin__.open".equals(qname) || "io.open".equals(qname)) && "mode".equals(name)) {
+          if (("__builtin__.open".equals(qname) || "io.open".equals(qname) || "os.fdopen".equals(qname)) && "mode".equals(name)) {
             final PyBuiltinCache cache = PyBuiltinCache.getInstance(anchor);
             final LanguageLevel level = LanguageLevel.forElement(anchor);
             argType = cache.getUnicodeType(level);
@@ -157,11 +158,16 @@ public class PyStdlibTypeProvider extends PyTypeProviderBase {
             }
           }
           final PyType paramType = getParameterTypeByQName(overloadedQName, name, anchor);
-          if (!PyTypeChecker.match(paramType, argType, context)) {
+          if (PyTypeChecker.match(paramType, argType, context)) {
+            if (argType != null && paramType != null) {
+              notNullParameterMatch = true;
+            }
+          }
+          else {
             matched = false;
           }
         }
-        if (matched) {
+        if (matched && notNullParameterMatch) {
           return rtype;
         }
       }
diff --git a/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes2.properties b/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes2.properties
index 93600d7b721c..54912ad380d8 100644
--- a/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes2.properties
+++ b/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes2.properties
@@ -1822,6 +1822,934 @@ decimal.Decimal.__neg__ = \
   :rtype: decimal.Decimal \n\
 
 
+# 10.1. os.path
+
+os.path.abspath = \
+  :type path: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.abspath.1 = \
+  :type path: bytes \n\
+  :rtype: bytes \n\
+
+os.path.abspath.2 = \
+  :type path: unicode \n\
+  :rtype: unicode \n\
+
+os.path.basename = \
+  :type p: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.basename.1 = \
+  :type p: bytes \n\
+  :rtype: bytes \n\
+
+os.path.basename.2 = \
+  :type p: unicode \n\
+  :rtype: unicode \n\
+
+os.path.commonprefix = \
+  :type m: collections.Iterable of string \n\
+  :rtype: bytes or unicode \n\
+
+os.path.commonprefix.1 = \
+  :type m: collections.Iterable of bytes \n\
+  :rtype: bytes \n\
+
+os.path.commonprefix.2 = \
+  :type m: collections.Iterable of unicode \n\
+  :rtype: unicode \n\
+
+os.path.dirname = \
+  :type p: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.dirname.1 = \
+  :type p: bytes \n\
+  :rtype: bytes \n\
+
+os.path.dirname.2 = \
+  :type p: unicode \n\
+  :rtype: unicode \n\
+
+os.path.exists = \
+  :type path: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.lexists = \
+  :type path: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.expanduser = \
+  :type path: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.expanduser.1 = \
+  :type path: bytes \n\
+  :rtype: bytes \n\
+
+os.path.expanduser.2 = \
+  :type path: unicode \n\
+  :rtype: unicode \n\
+
+os.path.expandvars = \
+  :type path: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.expandvars.1 = \
+  :type path: bytes \n\
+  :rtype: bytes \n\
+
+os.path.expandvars.2 = \
+  :type path: unicode \n\
+  :rtype: unicode \n\
+
+os.path.getatime = \
+  :type filename: bytes or unicode \n\
+  :rtype: int or float \n\
+
+os.path.getmtime = \
+  :type filename: bytes or unicode \n\
+  :rtype: int or float \n\
+
+os.path.getctime = \
+  :type filename: bytes or unicode \n\
+  :rtype: int or float \n\
+
+os.path.getsize = \
+  :type filename: bytes or unicode \n\
+  :rtype: int or long \n\
+
+os.path.isabs = \
+  :type s: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.isfile = \
+  :type path: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.isdir = \
+  :type s: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.islink = \
+  :type path: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.ismount = \
+  :type path: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.join = \
+  :type a: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.join.1 = \
+  :type a: bytes \n\
+  :rtype: bytes \n\
+
+os.path.join.2 = \
+  :type a: unicode \n\
+  :rtype: unicode \n\
+
+os.path.normcase = \
+  :type s: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.normcase.1 = \
+  :type s: bytes \n\
+  :rtype: bytes \n\
+
+os.path.normcase.2 = \
+  :type s: unicode \n\
+  :rtype: unicode \n\
+
+os.path.normpath = \
+  :type path: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.normpath.1 = \
+  :type path: bytes \n\
+  :rtype: bytes \n\
+
+os.path.normpath.2 = \
+  :type path: unicode \n\
+  :rtype: unicode \n\
+
+os.path.realpath = \
+  :type filename: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.realpath.1 = \
+  :type filename: bytes \n\
+  :rtype: bytes \n\
+
+os.path.realpath.2 = \
+  :type filename: unicode \n\
+  :rtype: unicode \n\
+
+os.path.relpath = \
+  :type path: bytes or unicode \n\
+  :type start: bytes or unicode \n\
+  :rtype: bytes or unicode \n\
+
+os.path.relpath.1 = \
+  :type path: bytes \n\
+  :rtype: bytes \n\
+
+os.path.relpath.2 = \
+  :type path: unicode \n\
+  :rtype: unicode \n\
+
+os.path.samefile = \
+  :type f1: bytes or unicode \n\
+  :type f2: bytes or unicode \n\
+  :rtype: bool \n\
+
+os.path.sameopenfile = \
+  :type fp1: int \n\
+  :type fp2: int \n\
+  :rtype: bool \n\
+
+os.path.samestat = \
+  :type s1: os.stat_result or tuple \n\
+  :type s2: os.stat_result or tuple \n\
+  :rtype: bool \n\
+
+os.path.split = \
+  :type p: bytes or unicode \n\
+  :rtype: (bytes or unicode, bytes or unicode) \n\
+
+os.path.split.1 = \
+  :type p: bytes \n\
+  :rtype: (bytes, bytes) \n\
+
+os.path.split.2 = \
+  :type p: unicode \n\
+  :rtype: (unicode, unicode) \n\
+
+os.path.splitdrive = \
+  :type p: bytes or unicode \n\
+  :rtype: (bytes or unicode, bytes or unicode) \n\
+
+os.path.splitdrive.1 = \
+  :type p: bytes \n\
+  :rtype: (bytes, bytes) \n\
+
+os.path.splitdrive.2 = \
+  :type p: unicode \n\
+  :rtype: (unicode, unicode) \n\
+
+os.path.splitext = \
+  :type p: bytes or unicode \n\
+  :rtype: (bytes or unicode, bytes or unicode) \n\
+
+os.path.splitext.1 = \
+  :type p: bytes \n\
+  :rtype: (bytes, bytes) \n\
+
+os.path.splitext.2 = \
+  :type p: unicode \n\
+  :rtype: (unicode, unicode) \n\
+
+os.path.splitunc = \
+  :type p: bytes or unicode \n\
+  :rtype: (bytes or unicode, bytes or unicode) \n\
+
+os.path.splitunc.1 = \
+  :type p: bytes \n\
+  :rtype: (bytes, bytes) \n\
+
+os.path.splitunc.2 = \
+  :type p: unicode \n\
+  :rtype: (unicode, unicode) \n\
+
+os.path.walk = \
+  :type top: bytes or unicode \n\
+  :rtype: None \n\
+
+
+## 10.10. shutil
+
+shutil.copyfile = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype None \n\
+
+shutil.copymode = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype None \n\
+
+shutil.copystat = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype None \n\
+
+shutil.copy = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype None \n\
+
+shutil.copy2 = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype None \n\
+
+shutil.copytree = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :type symlinks: bool \n\
+  :type ignore: collections.Callable or None \n\
+  :rtype None \n\
+
+shutil.rmtree = \
+  :type path: bytes or unicode \n\
+  :type ignore_errors: bool\n\
+  :type onerror: collections.Callable or None \n\
+  :rtype None \n\
+
+shutil.move = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype None \n\
+
+shutil.make_archive = \
+  :type base_name: bytes or unicode \n\
+  :type format: bytes or unicode \n\
+  :type root_dir: bytes or unicode or None \n\
+  :type base_dir: bytes or unicode or None \n\
+  :type verbose: bool or int \n\
+  :type dry_run: bool or int \n\
+  :type owner: bytes or unicode or int or None \n\
+  :type group: bytes or unicode or int or None \n\
+  :rtype: bytes or unicode \n\
+
+shutil.get_archive_formats = \
+  :rtype: list of (string, string) \n\
+
+shutil.register_archive_format = \
+  :type name: bytes or unicode \n\
+  :type function: collections.Callable \n\
+  :type extra_args: None or collections.Sequence of (string, object) \n\
+  :type description: bytes or unicode \n\
+  :rtype: None
+
+shutil.unregister_archive_format = \
+  :type name: bytes or unicode \n\
+  :rtype: None \n\
+
+
+## 15.1. os
+
+os.ctermid = \
+  :rtype: unicode \n\
+
+os.getegid = \
+  :rtype: int \n\
+
+os.geteuid = \
+  :rtype: int \n\
+
+os.getgid = \
+  :rtype: int \n\
+
+os.getgroups = \
+  :rtype: list of int \n\
+
+os.initgroups = \
+  :type username: string \n\
+  :type gid: int \n\
+  :rtype: None \n\
+
+os.getlogin = \
+  :rtype: unicode \n\
+
+os.getpgid = \
+  :type pid: int \n\
+  :rtype: int \n\
+
+os.getpgrp = \
+  :rtype: int \n\
+
+os.getpid = \
+  :rtype: int \n\
+
+os.getresuid = \
+  :rtype: (int, int, int) \n\
+
+os.getuid = \
+  :rtype: int \n\
+
+os.getenv = \
+  :type key: string \n\
+  :type default: object \n\
+  :rtype: string \n\
+
+os.putenv = \
+  :type key: bytes or unicode \n\
+  :type value: bytes or unicode \n\
+  :rtype: None \n\
+
+os.setegid = \
+  :type gid: int \n\
+  :rtype: None \n\
+
+os.seteuid = \
+  :type uid: int \n\
+  :rtype: None \n\
+
+os.setgid = \
+  :type gid: int \n\
+  :rtype: None \n\
+
+os.setgroups = \
+  :type p_list: list of int \n\
+  :rtype: None \n\
+
+os.setpgrp = \
+  :rtype: None \n\
+
+os.setpgid = \
+  :type pid: int \n\
+  :type pgrp: int \n\
+  :rtype: None \n\
+
+os.setregid = \
+  :type rgid: int \n\
+  :type egid: int \n\
+  :rtype: None \n\
+
+os.setresgid = \
+  :type rgid: int \n\
+  :type egid: int \n\
+  :type sgid: int \n\
+  :rtype: None \n\
+
+os.setresuid = \
+  :type ruid: int \n\
+  :type euid: int \n\
+  :type suid: int \n\
+  :rtype: None \n\
+
+os.setreuid = \
+  :type ruid: int \n\
+  :type euid: int \n\
+  :rtype: None \n\
+
+os.getsid = \
+  :type pid: int \n\
+  :rtype: int \n\
+
+os.setsid = \
+  :rtype: None \n\
+
+os.setuid = \
+  :type uid: int \n\
+  :rtype: None \n\
+
+os.strerror = \
+  :type code: int \n\
+  :rtype: unicode \n\
+
+os.umask = \
+  :type new_mask: int \n\
+  :rtype: int \n\
+
+os.uname = \
+  :rtype: (unicode, unicode, unicode, unicode, unicode) \n\
+
+os.unsetenv = \
+  :type key: string \n\
+  :rtype: None \n\
+
+os.fdopen = \
+  :type fd: int \n\
+  :type mode: string \n\
+  :type bufsize: int \n\
+  :rtype: file \n\
+
+os.fdopen.1 = \
+  :type mode: unicode \n\
+  :rtype: io.TextIOWrapper \n\
+
+os.fdopen.2 = \
+  :type mode: bytes \n\
+  :rtype: io.FileIO \n\
+
+os.popen = \
+  :type command: string \n\
+  :type mode: string \n\
+  :type bufsize: int \n\
+  :rtype: io.FileIO \n\
+
+os.tmpfile = \
+  :rtype: io.FileIO \n\
+
+os.popen2 = \
+  :type cmd: string \n\
+  :type mode: string \n\
+  :type bufsize: int \n\
+  :rtype: (io.FileIO, io.FileIO) \n\
+
+os.popen3 = \
+  :type cmd: string \n\
+  :type mode: string \n\
+  :type bufsize: int \n\
+  :rtype: (io.FileIO, io.FileIO, io.FileIO) \n\
+
+os.popen4 = \
+  :type cmd: string \n\
+  :type mode: string \n\
+  :type bufsize: int \n\
+  :rtype: (io.FileIO, io.FileIO) \n\
+
+os.close = \
+  :type fd: int \n\
+  :rtype: None \n\
+
+os.closerange = \
+  :type fd_low: int \n\
+  :type fd_high: int \n\
+  :rtype: None \n\
+
+os.dup = \
+  :type fd: int \n\
+  :rtype: int \n\
+
+os.dup2 = \
+  :type old_fd: int \n\
+  :type new_fd: int \n\
+  :rtype: None \n\
+
+os.fchmod = \
+  :type fd: int \n\
+  :type mode: int \n\
+  :rtype: None \n\
+
+os.fchown = \
+  :type fd: int \n\
+  :type uid: int \n\
+  :type gid: int \n\
+  :rtype: None \n\
+
+os.fdatasync = \
+  :type fildes: int \n\
+  :rtype: None \n\
+
+os.fpathconf = \
+  :type fd: int \n\
+  :type name: int or string \n\
+
+os.fstat = \
+  :type fd: int \n\
+  :rtype: os.stat_result \n\
+
+os.fstatvfs = \
+  :type fd: int \n\
+  :rtype: os.statvfs_result \n\
+
+os.fsync = \
+  :type filedes: int \n\
+  :rtype: None \n\
+
+os.ftruncate = \
+  :type fd: int \n\
+  :type length: int or long \n\
+  :rtype: None \n\
+
+os.isatty = \
+  :type fd: int \n\
+  :rtype: bool \n\
+
+os.lseek = \
+  :type fd: int \n\
+  :type pos: int or long \n\
+  :type how: int \n\
+  :rtype: None \n\
+
+os.open = \
+  :type filename: string \n\
+  :type mode: string \n\
+  :type bufsize: int \n\
+  :rtype: int \n\
+
+os.openpty = \
+  :rtype: (int, int) \n\
+
+os.pipe = \
+  :rtype: (int, int) \n\
+
+os.read = \
+  :type fd: int \b\
+  :type buffersize: int or long \n\
+  :rtype: bytes \n\
+
+os.tcgetpgrp = \
+  :type fd: int \n\
+  :rtype: int \n\
+
+os.tcsetpgrp = \
+  :type fd: int \n\
+  :type pgid: int \n\
+  :rtype: None \n\
+
+os.ttyname = \
+  :type fd: int \n\
+  :rtype: unicode \n\
+
+os.write = \
+  :type fd: int \n\
+  :type string: bytes \n\
+  :rtype: int \n\
+
+os.access = \
+  :type path: bytes or unicode \n\
+  :type mode: int \n\
+  :rtype: bool \n\
+
+os.chdir = \
+  :type path: bytes or unicode \n\
+  :rtype: None \n\
+
+os.fchdir = \
+  :type filedes: int \n\
+  :rtype: None \n\
+
+os.getcwd = \
+  :rtype: bytes \n\
+
+os.getcwdu = \
+  :rtype: unicode \n\
+
+os.chroot = \
+  :type path: bytes or unicode \n\
+  :rtype: None \n\
+
+os.chmod = \
+  :type path: bytes or unicode \n\
+  :type mode: int \n\
+  :rtype: None \n\
+
+os.chown = \
+  :type path: bytes or unicode \n\
+  :type uid: int \n\
+  :type gid: int \n\
+  :rtype: None \n\
+
+os.lchown = \
+  :type path: bytes or unicode \n\
+  :type uid: int \n\
+  :type gid: int \n\
+  :rtype: None \n\
+
+os.link = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype: None \n\
+
+os.listdir = \
+  :type path: bytes or unicode \n\
+  :rtype: list of string \n\
+
+os.listdir.1 = \
+  :type path: unicode \n\
+  :rtype: list of unicode \n\
+
+os.lstat = \
+  :type path: bytes or unicode \n\
+  :rtype: os.stat_result \n\
+
+os.mkfifo = \
+  :type filename: bytes or unicode \n\
+  :type mode: int \n\
+  :rtype: None \n\
+
+os.mknod = \
+  :type filename: bytes or unicode \n\
+  :type mode: int \n\
+  :type device: int \n\
+  :rtype: None \n\
+
+os.major = \
+  :type device: int \n\
+  :rtype: int \n\
+
+os.minor = \
+  :type device: int \n\
+  :rtype: int \n\
+
+os.makedev = \
+  :type major: int \n\
+  :type minor: int \n\
+  :rtype: int \n\
+
+os.mkdir = \
+  :type path: bytes or unicode \n\
+  :type mode: int \n\
+  :rtype: None \n\
+
+os.makedirs = \
+  :type name: bytes or unicode \n\
+  :type mode: int \n\
+  :rtype: None \n\
+
+os.pathconf = \
+  :type path: bytes or unicode \n\
+  :type name: int or string \n\
+
+os.readlink = \
+  :type path: bytes or unicode \n\
+  :rtype: string \n\
+
+os.readlink.1 = \
+  :type path: unicode \n\
+  :rtype: unicode \n\
+
+os.remove = \
+  :type path: bytes or unicode \n\
+  :rtype: None \n\
+
+os.removedirs = \
+  :type name: bytes or unicode \n\
+  :rtype: None \n\
+
+os.rename = \
+  :type old: bytes or unicode \n\
+  :type new: bytes or unicode \n\
+  :rtype: None \n\
+
+os.renames = \
+  :type old: bytes or unicode \n\
+  :type new: bytes or unicode \n\
+  :rtype: None \n\
+
+os.rmdir = \
+  :type path: bytes or unicode \n\
+  :rtype: None \n\
+
+os.stat = \
+  :type path: bytes or unicode \n\
+  :rtype: os.stat_result \n\
+
+os.stat_float_times = \
+  :type newval: bool or None \n\
+  :rtype: bool \n\
+
+os.statvfs = \
+  :type path: bytes or unicode \n\
+  :rtype: os.statvfs_result \n\
+
+os.symlink = \
+  :type src: bytes or unicode \n\
+  :type dst: bytes or unicode \n\
+  :rtype: None \n\
+
+os.tempnam = \
+  :type dir: bytes or unicode \n\
+  :type prefix: bytes or unicode \n\
+  :rtype: string \n\
+
+os.tmpnam = \
+  :rtype: string \n\
+
+os.unlink = \
+  :type path: bytes or unicode \n\
+  :rtype: None \n\
+
+os.utime = \
+  :type path: bytes or unicode \n\
+  :type atime: int or float \n\
+  :type mtime: int or float \n\
+  :rtype: None \n\
+
+os.walk = \
+  :type top: bytes or unicode \n\
+  :type topdown: bool \n\
+  :type followlinks: bool \n\
+  :rtype: collections.Iterable of (string, list of string, list of string) \n\
+
+os.walk.1 = \
+  :type top: bytes \n\
+  :type topdown: bool \n\
+  :type followlinks: bool \n\
+  :rtype: collections.Iterable of (bytes, list of bytes, list of bytes) \n\
+
+os.walk.2 = \
+  :type top: unicode \n\
+  :type topdown: bool \n\
+  :type followlinks: bool \n\
+  :rtype: collections.Iterable of (unicode, list of unicode, list of unicode) \n\
+
+os.execl = \
+  :type file: bytes or unicode \n\
+  :rtype: None \n\
+
+os.execle = \
+  :type file: bytes or unicode \n\
+  :rtype: None \n\
+
+os.execlp = \
+  :type file: bytes or unicode \n\
+  :rtype: None \n\
+
+os.execlpe = \
+  :type file: bytes or unicode \n\
+  :rtype: None \n\
+
+os.execv = \
+  :type path: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :rtype: None \n\
+
+os.execve = \
+  :type path: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :type env: collections.Mapping of (string, string) \n\
+  :rtype: None \n\
+
+os.execvp = \
+  :type file: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :rtype: None \n\
+
+os.execvpe = \
+  :type file: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :type env: collections.Mapping of (string, string) \n\
+  :rtype: None \n\
+
+os._exit = \
+  :type status: int \n\
+  :rtype: None \n\
+
+os.fork = \
+  :rtype: int \n\
+
+os.forkpty = \
+  :rtype: (int, int) \n\
+
+os.kill = \
+  :type pid: int \n\
+  :type sig: int \n\
+  :rtype: None \n\
+
+os.killpg = \
+  :type pgid: int \n\
+  :type sig: int \n\
+  :rtype: None \n\
+
+os.nice = \
+  :type inc: int \n\
+  :rtype: int \n\
+
+os.spawnl = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :rtype: int \n\
+
+os.spawnle = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :rtype: int \n\
+
+os.spawnlp = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :rtype: int \n\
+
+os.spawnlpe = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :rtype: int \n\
+
+os.spawnv = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :rtype: int \n\
+
+os.spawnve = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :type env: collections.Mapping of (string, string) \n\
+  :rtype: int \n\
+
+os.spawnvp = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :rtype: int \n\
+
+os.spawnvpe = \
+  :type mode: int \n\
+  :type file: bytes or unicode \n\
+  :type args: collections.Iterable of string \n\
+  :type env: collections.Mapping of (string, string) \n\
+  :rtype: int \n\
+
+os.system = \
+  :type command: bytes or unicode \n\
+  :rtype: int \n\
+
+os.times = \
+  :rtype: (float, float, float, float, float) \n\
+
+os.wait = \
+  :rtype: (int, int) \n\
+
+os.waitpid = \
+  :type pid: int \n\
+  :type options: int \n\
+  :rtype: (int, int) \n\
+
+os.wait3 = \
+  :type options: int \n\
+  :rtype: (int, int, resource.struct_rusage) \n\
+
+os.wait4 = \
+  :type pid: int \n\
+  :type options: int \n\
+  :rtype: (int, int, resource.struct_rusage) \n\
+
+os.WCOREDUMP = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.WIFCONTINUED = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.WIFSTOPPED = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.WIFSIGNALED = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.WIFEXITED = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.WEXITSTATUS = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.WSTOPSIG = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.WTERMSIG = \
+  :type status: int \n\
+  :rtype: bool \n\
+
+os.urandom = \
+  :type n: int \n\
+  :rtype: bytes \n\
+
+
 ## 15.2. io
 
 io.open = \
@@ -1948,6 +2876,13 @@ base64.b64decode = \
   :rtype: bytes \n\
 
 
+## 27.1. sys
+
+sys.exit = \
+  :type status: int \n\
+  :rtype: None \n\
+
+
 # 27.13. inspect
 
 # Fake <type 'generator'>
diff --git a/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes3.properties b/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes3.properties
index 1734dc72ba4a..df60add6ffec 100644
--- a/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes3.properties
+++ b/python/src/com/jetbrains/python/codeInsight/stdlib/StdlibTypes3.properties
@@ -370,6 +370,12 @@ __builtin__.range.__init__ = \
   :rtype: range of int \n\
 
 
+## 15.1. os
+
+os.getcwd = \
+  :rtype: str \n\
+
+
 ## 15.2. io
 
 io.IOBase.readlines = \
diff --git a/python/src/com/jetbrains/python/documentation/DocumentationBuilder.java b/python/src/com/jetbrains/python/documentation/DocumentationBuilder.java
index 746a74d99ec4..7523382ec8ef 100644
--- a/python/src/com/jetbrains/python/documentation/DocumentationBuilder.java
+++ b/python/src/com/jetbrains/python/documentation/DocumentationBuilder.java
@@ -88,7 +88,7 @@ class DocumentationBuilder {
                 if (property != null) {
                   is_property = true;
                   final AccessDirection dir = AccessDirection.of((PyElement)outer);
-                  Maybe<PyFunction> accessor = property.getByDirection(dir);
+                  Maybe<Callable> accessor = property.getByDirection(dir);
                   myProlog
                     .addItem("property ").addWith(TagBold, $().addWith(TagCode, $(element_name)))
                     .addItem(" of ").add(PythonDocumentationProvider.describeClass(cls, TagCode, true, true))
@@ -97,10 +97,10 @@ class DocumentationBuilder {
                     myBody.addItem(": ").addItem(property.getDoc()).addItem(BR);
                   }
                   else {
-                    final PyFunction getter = property.getGetter().valueOrNull();
-                    if (getter != null && getter != myElement) {
+                    final Callable getter = property.getGetter().valueOrNull();
+                    if (getter != null && getter != myElement && getter instanceof PyFunction) {
                       // not in getter, getter's doc comment may be useful
-                      PyStringLiteralExpression docstring = getter.getDocStringExpression();
+                      PyStringLiteralExpression docstring = ((PyFunction)getter).getDocStringExpression();
                       if (docstring != null) {
                         myProlog
                           .addItem(BR).addWith(TagItalic, $("Copied from getter:")).addItem(BR)
diff --git a/python/src/com/jetbrains/python/inspections/PyPropertyAccessInspection.java b/python/src/com/jetbrains/python/inspections/PyPropertyAccessInspection.java
index cd49305e2ae1..6f36c9b516d5 100644
--- a/python/src/com/jetbrains/python/inspections/PyPropertyAccessInspection.java
+++ b/python/src/com/jetbrains/python/inspections/PyPropertyAccessInspection.java
@@ -90,7 +90,7 @@ public class PyPropertyAccessInspection extends PyInspection {
     }
 
     private void checkAccessor(PyExpression node, String name, AccessDirection dir, Property property) {
-      final Maybe<PyFunction> accessor = property.getByDirection(dir);
+      final Maybe<Callable> accessor = property.getByDirection(dir);
       if (accessor.isDefined() && accessor.value() == null) {
         final String message;
         if (dir == AccessDirection.WRITE) {
diff --git a/python/src/com/jetbrains/python/inspections/PyPropertyDefinitionInspection.java b/python/src/com/jetbrains/python/inspections/PyPropertyDefinitionInspection.java
index 5e174b23caff..1733ba9c750c 100644
--- a/python/src/com/jetbrains/python/inspections/PyPropertyDefinitionInspection.java
+++ b/python/src/com/jetbrains/python/inspections/PyPropertyDefinitionInspection.java
@@ -119,8 +119,10 @@ public class PyPropertyDefinitionInspection extends PyInspection {
           else {
             // @property; we only check getter, others are checked by visitPyFunction
             // getter is always present with this form
-            final PyFunction function = property.getGetter().valueOrNull();
-            checkGetter(function, getFunctionMarkingElement(function));
+            final Callable callable = property.getGetter().valueOrNull();
+            if (callable instanceof PyFunction) {
+              checkGetter(callable, getFunctionMarkingElement((PyFunction)callable));
+            }
           }
           return false;  // always want more
         }
@@ -278,7 +280,7 @@ public class PyPropertyDefinitionInspection extends PyInspection {
                    (element instanceof PyYieldExpression);
           }
         });
-        hasReturns = returnStatements.length > 0; 
+        hasReturns = returnStatements.length > 0;
       }
       else {
         PyReferenceExpression callSite = being_checked instanceof PyReferenceExpression ? (PyReferenceExpression) being_checked : null;
diff --git a/python/src/com/jetbrains/python/psi/Property.java b/python/src/com/jetbrains/python/psi/Property.java
index 5313ff37070f..aad101b0a575 100644
--- a/python/src/com/jetbrains/python/psi/Property.java
+++ b/python/src/com/jetbrains/python/psi/Property.java
@@ -18,19 +18,19 @@ public interface Property {
    * @return the setter: a method or null if defined, or something else callable if undefined.
    */
   @NotNull
-  Maybe<PyFunction> getSetter();
+  Maybe<Callable> getSetter();
 
   /**
    * @return the getter: a method or null if defined, or something else callable if undefined.
    */
   @NotNull
-  Maybe<PyFunction> getGetter();
+  Maybe<Callable> getGetter();
 
   /**
    * @return the deleter: a method or null if defined, or something else callable if undefined.
    */
   @NotNull
-  Maybe<PyFunction> getDeleter();
+  Maybe<Callable> getDeleter();
 
   /**
    * @return doc string as known to property() call. If null, see getter's doc.
@@ -39,7 +39,7 @@ public interface Property {
   String getDoc();
 
   /**
-   * @return the target to which the result of property() call is assigned. For things defined via @property, it is null. 
+   * @return the target to which the result of property() call is assigned. For things defined via @property, it is null.
    */
   @Nullable
   PyTargetExpression getDefinitionSite();
@@ -49,6 +49,6 @@ public interface Property {
    * @return getter, setter, or deleter.
    */
   @NotNull
-  Maybe<PyFunction> getByDirection(@NotNull AccessDirection direction);
+  Maybe<Callable> getByDirection(@NotNull AccessDirection direction);
 
 }
diff --git a/python/src/com/jetbrains/python/psi/impl/PropertyBunch.java b/python/src/com/jetbrains/python/psi/impl/PropertyBunch.java
index 34d50ca2f25c..ac3f339c11c2 100644
--- a/python/src/com/jetbrains/python/psi/impl/PropertyBunch.java
+++ b/python/src/com/jetbrains/python/psi/impl/PropertyBunch.java
@@ -49,8 +49,8 @@ public abstract class PropertyBunch<MType> {
    * @param ref a reference as an argument in property() call
    * @return value we want to store (resolved callable, name, etc)
    */
-  protected abstract @Nullable MType translate(@NotNull PyReferenceExpression ref);
-
+  @Nullable
+  protected abstract MType translate(@NotNull PyExpression ref);
 
   @Nullable
   public static PyCallExpression findPropertyCallSite(@Nullable PyExpression source) {
@@ -140,10 +140,6 @@ public abstract class PropertyBunch<MType> {
   }
 
   private static <MType> Maybe<MType> translateIfSet(PropertyBunch<MType> target, PyExpression accessor) {
-    // TODO[yole] I don't quite understand this subtle distinction (why an accessor defined with lambda must be treated as defined=false)
-    if (accessor != null && !(accessor instanceof PyReferenceExpression)) {
-      return new Maybe<MType>();
-    }
-    return new Maybe<MType>(accessor == null ? null : target.translate((PyReferenceExpression) accessor));
+    return new Maybe<MType>(accessor == null ? null : target.translate(accessor));
   }
 }
diff --git a/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java b/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
index 543260805f80..6e22ce19aea1 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
@@ -5,10 +5,7 @@ import com.intellij.lang.ASTNode;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.NotNullLazyValue;
 import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.psi.PsiElement;
-import com.intellij.psi.PsiFile;
-import com.intellij.psi.ResolveState;
-import com.intellij.psi.StubBasedPsiElement;
+import com.intellij.psi.*;
 import com.intellij.psi.scope.PsiScopeProcessor;
 import com.intellij.psi.search.LocalSearchScope;
 import com.intellij.psi.search.SearchScope;
@@ -42,6 +39,8 @@ import org.jetbrains.annotations.Nullable;
 import javax.swing.*;
 import java.util.*;
 
+import static com.jetbrains.python.psi.stubs.PyTargetExpressionStub.InitializerType.CallExpression;
+
 /**
  * @author yole
  */
@@ -492,8 +491,8 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
     return proc.getResult();
   }
 
-  private final static Maybe<PyFunction> UNKNOWN_CALL = new Maybe<PyFunction>(); // denotes _not_ a PyFunction, actually
-  private final static Maybe<PyFunction> NONE = new Maybe<PyFunction>(null); // denotes an explicit None
+  private final static Maybe<Callable> UNKNOWN_CALL = new Maybe<Callable>(); // denotes _not_ a PyFunction, actually
+  private final static Maybe<Callable> NONE = new Maybe<Callable>(null); // denotes an explicit None
 
   /**
    * @param name name of the property
@@ -541,9 +540,9 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
       }
     }
     for (Map.Entry<String, List<PyFunction>> entry: grouped.entrySet()) {
-      Maybe<PyFunction> getter = NONE;
-      Maybe<PyFunction> setter = NONE;
-      Maybe<PyFunction> deleter = NONE;
+      Maybe<Callable> getter = NONE;
+      Maybe<Callable> setter = NONE;
+      Maybe<Callable> deleter = NONE;
       String doc = null;
       final String decoratorName = entry.getKey();
       for (PyFunction method : entry.getValue()) {
@@ -553,13 +552,13 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
             final PyQualifiedName qname = deco.getQualifiedName();
             if (qname != null) {
               if (qname.matches(PyNames.PROPERTY)) {
-                getter = new Maybe<PyFunction>(method);
+                getter = new Maybe<Callable>(method);
               }
               else if (useAdvancedSyntax && qname.matches(decoratorName, PyNames.SETTER)) {
-                setter = new Maybe<PyFunction>(method);
+                setter = new Maybe<Callable>(method);
               }
               else if (useAdvancedSyntax && qname.matches(decoratorName, PyNames.DELETER)) {
-                deleter = new Maybe<PyFunction>(method);
+                deleter = new Maybe<Callable>(method);
               }
             }
           }
@@ -574,14 +573,14 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
     return null;
   }
 
-  private Maybe<PyFunction> fromPacked(Maybe<String> maybeName) {
+  private Maybe<Callable> fromPacked(Maybe<String> maybeName) {
     if (maybeName.isDefined()) {
       final String value = maybeName.value();
       if (value == null || PyNames.NONE.equals(value)) {
         return NONE;
       }
       PyFunction method = findMethodByName(value, true);
-      if (method != null) return new Maybe<PyFunction>(method);
+      if (method != null) return new Maybe<Callable>(method);
     }
     return UNKNOWN_CALL;
   }
@@ -595,15 +594,23 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
           final PyTargetExpressionStub targetStub = (PyTargetExpressionStub)substub;
           PropertyStubStorage prop = targetStub.getCustomStub(PropertyStubStorage.class);
           if (prop != null && (name == null || name.equals(targetStub.getName()))) {
-            Maybe<PyFunction> getter = fromPacked(prop.getGetter());
-            Maybe<PyFunction> setter = fromPacked(prop.getSetter());
-            Maybe<PyFunction> deleter = fromPacked(prop.getDeleter());
+            Maybe<Callable> getter = fromPacked(prop.getGetter());
+            Maybe<Callable> setter = fromPacked(prop.getSetter());
+            Maybe<Callable> deleter = fromPacked(prop.getDeleter());
             String doc = prop.getDoc();
             if (getter != NONE || setter != NONE || deleter != NONE) {
               final PropertyImpl property = new PropertyImpl(targetStub.getName(), getter, setter, deleter, doc, targetStub.getPsi());
               if (propertyProcessor == null || propertyProcessor.process(property)) return property;
             }
           }
+          final PyQualifiedName initializer = targetStub.getInitializer();
+          if (targetStub.getInitializerType() == CallExpression && initializer != null && PyNames.PROPERTY.equals(initializer.toString())) {
+            final PropertyImpl property = new PropertyImpl(targetStub.getName(), UNKNOWN_CALL, UNKNOWN_CALL, UNKNOWN_CALL,
+                                                           null, targetStub.getPsi());
+            if (propertyProcessor == null || propertyProcessor.process(property)) {
+              return property;
+            }
+          }
         }
       }
     }
@@ -702,10 +709,10 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
     return null;
   }
 
-  private static class PropertyImpl extends PropertyBunch<PyFunction> implements Property {
+  private static class PropertyImpl extends PropertyBunch<Callable> implements Property {
     private final String myName;
 
-    private PropertyImpl(String name, Maybe<PyFunction> getter, Maybe<PyFunction> setter, Maybe<PyFunction> deleter, String doc, PyTargetExpression site) {
+    private PropertyImpl(String name, Maybe<Callable> getter, Maybe<Callable> setter, Maybe<Callable> deleter, String doc, PyTargetExpression site) {
       myName = name;
       myDeleter = deleter;
       myGetter = getter;
@@ -724,7 +731,7 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
 
     @NotNull
     @Override
-    public Maybe<PyFunction> getByDirection(@NotNull AccessDirection direction) {
+    public Maybe<Callable> getByDirection(@NotNull AccessDirection direction) {
       switch (direction) {
         case READ:    return myGetter;
         case WRITE:   return mySetter;
@@ -733,12 +740,19 @@ public class PyClassImpl extends PyPresentableElementImpl<PyClassStub> implement
       throw new IllegalArgumentException("Unknown direction " + PyUtil.nvl(direction));
     }
 
+    @Nullable
     @Override
-    protected PyFunction translate(@NotNull PyReferenceExpression ref) {
-      if (PyNames.NONE.equals(ref.getName())) return null; // short-circuit a common case
-      PsiElement something = ref.getReference().resolve();
-      if (something instanceof PyFunction) {
-        return (PyFunction)something;
+    protected Callable translate(@NotNull PyExpression expr) {
+      if (PyNames.NONE.equals(expr.getName())) return null; // short-circuit a common case
+      if (expr instanceof Callable) {
+        return (Callable)expr;
+      }
+      final PsiReference ref = expr.getReference();
+      if (ref != null) {
+        PsiElement something = ref.resolve();
+        if (something instanceof Callable) {
+          return (Callable)something;
+        }
       }
       return null;
     }
diff --git a/python/src/com/jetbrains/python/psi/impl/PyDecoratorListImpl.java b/python/src/com/jetbrains/python/psi/impl/PyDecoratorListImpl.java
index 83ea5bd549d9..c923ee3b0e2f 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyDecoratorListImpl.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyDecoratorListImpl.java
@@ -2,11 +2,10 @@ package com.jetbrains.python.psi.impl;
 
 import com.intellij.lang.ASTNode;
 import com.jetbrains.python.PyElementTypes;
-import com.jetbrains.python.psi.PyDecoratorList;
-import com.jetbrains.python.psi.PyExpression;
-import com.jetbrains.python.psi.stubs.PyDecoratorListStub;
 import com.jetbrains.python.psi.PyDecorator;
+import com.jetbrains.python.psi.PyDecoratorList;
 import com.jetbrains.python.psi.PyElementVisitor;
+import com.jetbrains.python.psi.stubs.PyDecoratorListStub;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -38,8 +37,8 @@ public class PyDecoratorListImpl extends PyBaseElementImpl<PyDecoratorListStub>
   public PyDecorator findDecorator(String name) {
     final PyDecorator[] decorators = getDecorators();
     for (PyDecorator decorator : decorators) {
-      final PyExpression callee = decorator.getCallee();
-      if (callee != null && name.equals(callee.getText())) {
+      final PyQualifiedName qName = decorator.getQualifiedName();
+      if (qName != null && name.equals(qName.toString())) {
         return decorator;
       }
     }
diff --git a/python/src/com/jetbrains/python/psi/impl/PyReferenceExpressionImpl.java b/python/src/com/jetbrains/python/psi/impl/PyReferenceExpressionImpl.java
index 371fcec7dc1c..743c61a0be8d 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyReferenceExpressionImpl.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyReferenceExpressionImpl.java
@@ -19,7 +19,9 @@ import com.jetbrains.python.console.PydevConsoleRunner;
 import com.jetbrains.python.console.completion.PydevConsoleReference;
 import com.jetbrains.python.console.pydev.ConsoleCommunication;
 import com.jetbrains.python.psi.*;
-import com.jetbrains.python.psi.impl.references.*;
+import com.jetbrains.python.psi.impl.references.PyImportReference;
+import com.jetbrains.python.psi.impl.references.PyQualifiedReference;
+import com.jetbrains.python.psi.impl.references.PyReferenceImpl;
 import com.jetbrains.python.psi.resolve.*;
 import com.jetbrains.python.psi.types.*;
 import com.jetbrains.python.refactoring.PyDefUseUtil;
@@ -218,24 +220,39 @@ public class PyReferenceExpressionImpl extends PyElementImpl implements PyRefere
 
   @Nullable
   public Ref<PyType> getTypeOfProperty(@NotNull TypeEvalContext context) {
-    PyExpression qualifier = getQualifier();
+    final PyExpression qualifier = getQualifier();
     final String name = getName();
     if (name != null && qualifier != null) {
-      PyType qualifierType = context.getType(qualifier);
-      if (qualifierType instanceof PyClassType) {
-        final PyClassType classType = (PyClassType)qualifierType;
-        PyClass pyClass = classType.getPyClass();
-        if (pyClass != null) {
-          Property property = pyClass.findProperty(name);
-          if (property != null) {
-            if (classType.isDefinition()) {
-              return Ref.<PyType>create(PyBuiltinCache.getInstance(pyClass).getObjectType(PyNames.PROPERTY));
-            }
-            final Maybe<PyFunction> accessor = property.getByDirection(AccessDirection.of(this));
-            final PyFunction function = accessor.valueOrNull();
-            final PyType type = (function != null) ? function.getReturnType(context, this) : null;
-            return Ref.create(type);
+      final PyType qualifierType = context.getType(qualifier);
+      return getTypeOfProperty(qualifierType, name, context);
+    }
+    return null;
+  }
+
+  @Nullable
+  private Ref<PyType> getTypeOfProperty(@Nullable PyType qualifierType, @NotNull String name, @NotNull TypeEvalContext context) {
+    if (qualifierType instanceof PyClassType) {
+      final PyClassType classType = (PyClassType)qualifierType;
+      PyClass pyClass = classType.getPyClass();
+      if (pyClass != null) {
+        Property property = pyClass.findProperty(name);
+        if (property != null) {
+          if (classType.isDefinition()) {
+            return Ref.<PyType>create(PyBuiltinCache.getInstance(pyClass).getObjectType(PyNames.PROPERTY));
           }
+          final Maybe<Callable> accessor = property.getByDirection(AccessDirection.of(this));
+          final Callable callable = accessor.valueOrNull();
+          final PyType type = (callable != null) ? callable.getReturnType(context, this) : null;
+          return Ref.create(type);
+        }
+      }
+    }
+    else if (qualifierType instanceof PyUnionType) {
+      final PyUnionType unionType = (PyUnionType)qualifierType;
+      for (PyType type : unionType.getMembers()) {
+        final Ref<PyType> result = getTypeOfProperty(type, name, context);
+        if (result != null) {
+          return result;
         }
       }
     }
diff --git a/python/src/com/jetbrains/python/psi/resolve/ResolveImportUtil.java b/python/src/com/jetbrains/python/psi/resolve/ResolveImportUtil.java
index 5fa0c29893c9..fd8649d0861b 100644
--- a/python/src/com/jetbrains/python/psi/resolve/ResolveImportUtil.java
+++ b/python/src/com/jetbrains/python/psi/resolve/ResolveImportUtil.java
@@ -549,6 +549,10 @@ public class ResolveImportUtil {
         components.set(0, "collections");
         return PyQualifiedName.fromComponents(components);
       }
+      else if (head.equals("posix") || head.equals("nt")) {
+        components.set(0, "os");
+        return PyQualifiedName.fromComponents(components);
+      }
       else if (head.equals("_functools")) {
         components.set(0, "functools");
         return PyQualifiedName.fromComponents(components);
@@ -565,7 +569,7 @@ public class ResolveImportUtil {
         components.set(0, "datetime");
         return PyQualifiedName.fromComponents(components);
       }
-      else if (head.equals("ntpath") | head.equals("posixpath")) {
+      else if (head.equals("ntpath") || head.equals("posixpath") || head.equals("path")) {
         final List<String> result = new ArrayList<String>();
         result.add("os");
         components.set(0, "path");
diff --git a/python/src/com/jetbrains/python/psi/stubs/PropertyStubStorage.java b/python/src/com/jetbrains/python/psi/stubs/PropertyStubStorage.java
index 69a17b166e73..1030bd1bdd20 100644
--- a/python/src/com/jetbrains/python/psi/stubs/PropertyStubStorage.java
+++ b/python/src/com/jetbrains/python/psi/stubs/PropertyStubStorage.java
@@ -4,7 +4,6 @@ import com.intellij.psi.stubs.StubInputStream;
 import com.intellij.psi.stubs.StubOutputStream;
 import com.intellij.util.io.StringRef;
 import com.jetbrains.python.psi.PyExpression;
-import com.jetbrains.python.psi.PyReferenceExpression;
 import com.jetbrains.python.psi.impl.PropertyBunch;
 import com.jetbrains.python.psi.impl.PyQualifiedName;
 import com.jetbrains.python.psi.impl.stubs.CustomTargetExpressionStub;
@@ -23,11 +22,10 @@ import java.io.IOException;
  */
 public class PropertyStubStorage extends PropertyBunch<String> implements CustomTargetExpressionStub {
 
+  @Nullable
   @Override
-  protected String translate(@NotNull PyReferenceExpression ref) {
-    final String name = ref.getName();
-    assert name != null;
-    return name;
+  protected String translate(@NotNull PyExpression ref) {
+    return ref.getName();
   }
 
   private static final String IMPOSSIBLE_NAME = "#";
diff --git a/python/src/com/jetbrains/python/psi/types/PyClassType.java b/python/src/com/jetbrains/python/psi/types/PyClassType.java
index c562c50421e4..e73bac12ed7b 100644
--- a/python/src/com/jetbrains/python/psi/types/PyClassType.java
+++ b/python/src/com/jetbrains/python/psi/types/PyClassType.java
@@ -122,7 +122,7 @@ public class PyClassType extends UserDataHolderBase implements PyCallableType {
     if (resolveContext.allowProperties()) {
       Property property = myClass.findProperty(name);
       if (property != null) {
-        Maybe<PyFunction> accessor = property.getByDirection(direction);
+        Maybe<Callable> accessor = property.getByDirection(direction);
         if (accessor.isDefined()) {
           Callable accessor_code = accessor.value();
           ResolveResultList ret = new ResolveResultList();
diff --git a/python/src/com/jetbrains/python/psi/types/PyTypeChecker.java b/python/src/com/jetbrains/python/psi/types/PyTypeChecker.java
index 6fb1e30fcc5c..e5062b6fb3cb 100644
--- a/python/src/com/jetbrains/python/psi/types/PyTypeChecker.java
+++ b/python/src/com/jetbrains/python/psi/types/PyTypeChecker.java
@@ -124,6 +124,12 @@ public class PyTypeChecker {
         return true;
       }
     }
+    if (actual instanceof PyFunctionType && expected instanceof PyClassType) {
+      final PyClass superClass = ((PyClassType)expected).getPyClass();
+      if (superClass != null && PyNames.CALLABLE.equals(superClass.getName())) {
+        return true;
+      }
+    }
     final String superName = expected.getName();
     final String subName = actual.getName();
     // TODO: No inheritance check for builtin numerics at this moment
@@ -376,7 +382,10 @@ public class PyTypeChecker {
     if (callSite == null) {
       return null;
     }
-    final PsiElement parent = callSite.getParent();
+    PsiElement parent = callSite.getParent();
+    while (parent instanceof PyParenthesizedExpression) {
+      parent = ((PyParenthesizedExpression)parent).getContainedExpression();
+    }
     if (parent instanceof PyCallExpression) {
       return analyzeCall((PyCallExpression)parent, context);
     }
diff --git a/python/src/com/jetbrains/python/refactoring/rename/RenamePyFunctionProcessor.java b/python/src/com/jetbrains/python/refactoring/rename/RenamePyFunctionProcessor.java
index eefceb611661..72e8cf569d41 100644
--- a/python/src/com/jetbrains/python/refactoring/rename/RenamePyFunctionProcessor.java
+++ b/python/src/com/jetbrains/python/refactoring/rename/RenamePyFunctionProcessor.java
@@ -6,6 +6,7 @@ import com.intellij.psi.PsiElement;
 import com.intellij.util.Processor;
 import com.jetbrains.python.PyNames;
 import com.jetbrains.python.codeInsight.PyCodeInsightSettings;
+import com.jetbrains.python.psi.Callable;
 import com.jetbrains.python.psi.Property;
 import com.jetbrains.python.psi.PyClass;
 import com.jetbrains.python.psi.PyFunction;
@@ -101,10 +102,10 @@ public class RenamePyFunctionProcessor extends RenamePyElementProcessor {
     }
   }
 
-  private static void addRename(Map<PsiElement, String> renames, String newName, Maybe<PyFunction> accessor) {
-    final PyFunction function = accessor.valueOrNull();
-    if (function != null) {
-      renames.put(function, newName);
+  private static void addRename(Map<PsiElement, String> renames, String newName, Maybe<Callable> accessor) {
+    final Callable callable = accessor.valueOrNull();
+    if (callable instanceof PyFunction) {
+      renames.put(callable, newName);
     }
   }
 }
diff --git a/python/testSrc/com/jetbrains/python/PyClassicPropertyTest.java b/python/testSrc/com/jetbrains/python/PyClassicPropertyTest.java
index 332c586e594b..90de66323c72 100644
--- a/python/testSrc/com/jetbrains/python/PyClassicPropertyTest.java
+++ b/python/testSrc/com/jetbrains/python/PyClassicPropertyTest.java
@@ -16,7 +16,7 @@ public class PyClassicPropertyTest extends PyTestCase {
 
   public void testV1() throws Exception {
     Property p;
-    Maybe<PyFunction> accessor;
+    Maybe<Callable> accessor;
     p = myClass.findProperty("v1");
     assertNotNull(p);
     assertNull(p.getDoc());
@@ -40,7 +40,7 @@ public class PyClassicPropertyTest extends PyTestCase {
 
   public void testV2() throws Exception {
     Property p;
-    Maybe<PyFunction> accessor;
+    Maybe<Callable> accessor;
     p = myClass.findProperty("v2");
     assertNotNull(p);
     assertEquals("doc of v2", p.getDoc());
@@ -65,7 +65,7 @@ public class PyClassicPropertyTest extends PyTestCase {
 
   public void testV3() throws Exception {
     Property p;
-    Maybe<PyFunction> accessor;
+    Maybe<Callable> accessor;
     p = myClass.findProperty("v3");
     assertNotNull(p);
     assertNull(p.getDoc());
@@ -73,7 +73,7 @@ public class PyClassicPropertyTest extends PyTestCase {
     assertEquals("v3", site.getText());
 
     accessor = p.getGetter();
-    assertFalse(accessor.isDefined());
+    assertTrue(accessor.isDefined());
 
     accessor = p.getSetter();
     assertTrue(accessor.isDefined());
@@ -88,7 +88,7 @@ public class PyClassicPropertyTest extends PyTestCase {
   /* NOTE: we don't support this yet
   public void testV4() throws Exception {
     Property p;
-    Maybe<PyFunction> accessor;
+    Maybe<Callable> accessor;
     p = myClass.findProperty("v4");
     assertNotNull(p);
     assertEquals("otherworldly", p.getDoc());
diff --git a/python/testSrc/com/jetbrains/python/PyDecoratedPropertyTest.java b/python/testSrc/com/jetbrains/python/PyDecoratedPropertyTest.java
index f84887e367df..67414bcfbf5e 100644
--- a/python/testSrc/com/jetbrains/python/PyDecoratedPropertyTest.java
+++ b/python/testSrc/com/jetbrains/python/PyDecoratedPropertyTest.java
@@ -18,7 +18,7 @@ public class PyDecoratedPropertyTest extends PyTestCase {
 
   public void testW1() throws Exception {
     Property p;
-    Maybe<PyFunction> accessor;
+    Maybe<Callable> accessor;
     final String name = "w1";
     p = myClass.findProperty(name);
     assertNotNull(p);
@@ -43,7 +43,7 @@ public class PyDecoratedPropertyTest extends PyTestCase {
 
   public void testW2() throws Exception {
     Property p;
-    Maybe<PyFunction> accessor;
+    Maybe<Callable> accessor;
     final String name = "w2";
     p = myClass.findProperty(name);
     assertNotNull(p);
@@ -52,9 +52,11 @@ public class PyDecoratedPropertyTest extends PyTestCase {
 
     accessor = p.getGetter();
     assertTrue(accessor.isDefined());
-    assertNotNull(accessor.value());
-    assertEquals("w2", accessor.value().getName());
-    assertEquals("doc of "+name, accessor.value().getDocStringExpression().getStringValue());
+    final Callable callable = accessor.value();
+    assertNotNull(callable);
+    assertEquals("w2", callable.getName());
+    assertInstanceOf(callable, PyFunction.class);
+    assertEquals("doc of " + name, ((PyFunction)callable).getDocStringExpression().getStringValue());
 
     accessor = p.getSetter();
     assertTrue(accessor.isDefined());
diff --git a/python/testSrc/com/jetbrains/python/PyStubsTest.java b/python/testSrc/com/jetbrains/python/PyStubsTest.java
index 62647916c668..3262bb3b1a47 100644
--- a/python/testSrc/com/jetbrains/python/PyStubsTest.java
+++ b/python/testSrc/com/jetbrains/python/PyStubsTest.java
@@ -104,12 +104,12 @@ public class PyStubsTest extends PyTestCase {
       assertEquals("BarClass", pyClass.getName());
 
       Property prop = pyClass.findProperty("value");
-      Maybe<PyFunction> maybe_function = prop.getGetter();
+      Maybe<Callable> maybe_function = prop.getGetter();
       assertTrue(maybe_function.isDefined());
       assertEquals(pyClass.getMethods()[0], maybe_function.value());
 
       Property setvalueProp = pyClass.findProperty("setvalue");
-      Maybe<PyFunction> setter = setvalueProp.getSetter();
+      Maybe<Callable> setter = setvalueProp.getSetter();
       assertTrue(setter.isDefined());
       assertEquals("__set", setter.value().getName());
 
diff --git a/python/testSrc/com/jetbrains/python/PyTypeTest.java b/python/testSrc/com/jetbrains/python/PyTypeTest.java
index 24b6b9bcefe2..60b9f66241d9 100644
--- a/python/testSrc/com/jetbrains/python/PyTypeTest.java
+++ b/python/testSrc/com/jetbrains/python/PyTypeTest.java
@@ -371,6 +371,20 @@ public class PyTypeTest extends PyTestCase {
            "expr = h()\n");
   }
 
+  public void testPropertyOfUnionType() {
+    PyExpression expr = parseExpr("def f():\n" +
+                                  "    '''\n" +
+                                  "    :rtype: int or slice\n" +
+                                  "    '''\n" +
+                                  "    raise NotImplementedError\n" +
+                                  "\n" +
+                                  "x = f()\n" +
+                                  "expr = x.start\n");
+    TypeEvalContext context = TypeEvalContext.slow().withTracing();
+    PyType actual = expr.getType(context);
+    assertNull(actual);
+  }
+
   private PyExpression parseExpr(String text) {
     myFixture.configureByText(PythonFileType.INSTANCE, text);
     return myFixture.findElementByText("expr", PyExpression.class);