diff --git a/Python-2.7.13/pyconfig.h b/Python-2.7.13/pyconfig.h
index ce867a6304..693c93b63e 100644
--- a/Python-2.7.13/pyconfig.h
+++ b/Python-2.7.13/pyconfig.h
@@ -259,9 +259,6 @@
 /* Define to 1 if you have the `ftello' function. */
 #define HAVE_FTELLO 1
 
-/* Define to 1 if you have the `ftime' function. */
-#define HAVE_FTIME 1
-
 /* Define to 1 if you have the `ftruncate' function. */
 #define HAVE_FTRUNCATE 1
 
diff --git a/build/cpython_defs.py b/build/cpython_defs.py
index e5d4d17c38..9e6fa3a23f 100755
--- a/build/cpython_defs.py
+++ b/build/cpython_defs.py
@@ -305,8 +305,9 @@ def __call__(self, rel_path, def_name, method_name):
 
     # Auto-filtering gave false-positives here.
     # We don't need top-level next().  The method should be good enough.
+    # iter is a field name
     if (basename == 'bltinmodule.c' and
-        method_name in ('compile', 'format', 'next', 'vars')):
+        method_name in ('compile', 'format', 'next', 'vars', 'iter')):
       return False
     if basename == 'bltinmodule.c':
       # Get "bootstrapping error" without this.
diff --git a/build/oil-defs/native/libc.c/methods.def b/build/oil-defs/native/libc.c/methods.def
index 456652273a..e9fb7b94fb 100644
--- a/build/oil-defs/native/libc.c/methods.def
+++ b/build/oil-defs/native/libc.c/methods.def
@@ -9,5 +9,6 @@ static PyMethodDef methods[] = {
   {"print_time", func_print_time, METH_VARARGS},
   {"gethostname", socket_gethostname, METH_NOARGS},
   {"get_terminal_width", func_get_terminal_width, METH_NOARGS},
+  {"wcswidth", func_wcswidth, METH_VARARGS},
   {0},
 };
diff --git a/core/comp_ui.py b/core/comp_ui.py
index 21d0ae2c7e..d26d2bba62 100644
--- a/core/comp_ui.py
+++ b/core/comp_ui.py
@@ -32,7 +32,8 @@
 def _PromptLen(prompt_str):
   """Ignore all characters between \x01 and \x02 and handle unicode characters.
   In particular, the display width of a string may be different from either the
-  number of bytes or the number of unicode characters."""
+  number of bytes or the number of unicode characters.
+  Additionally, if there are multiple lines in the prompt, only give the length of the last line."""
   escaped = False
   display_str = ""
   for c in prompt_str:
@@ -42,11 +43,15 @@ def _PromptLen(prompt_str):
       escaped = False
     elif not escaped:
       display_str += c
+  last_line = display_str.split('\n')[-1]
   try:
-    return libc.wcswidth(display_str)
+    width = libc.wcswidth(last_line)
   # en_US.UTF-8 locale missing, just return the number of bytes
   except (SystemError, UnicodeError):
     return len(display_str)
+  if width == -1:
+    return len(display_str)
+  return width
 
 
 class PromptState(object):
diff --git a/core/comp_ui_test.py b/core/comp_ui_test.py
index e8b1484300..7650f7ce6c 100755
--- a/core/comp_ui_test.py
+++ b/core/comp_ui_test.py
@@ -165,6 +165,14 @@ def testValidEscapes(self):
         comp_ui._PromptLen("\x01\x02 hi \x01hi\x02 \x01\x02 hello"),
         len(" hi   hello"))
 
+  def testNewline(self):
+    self.assertEqual(comp_ui._PromptLen("\n"), 0)
+    self.assertEqual(comp_ui._PromptLen("abc\ndef"), 3)
+    self.assertEqual(comp_ui._PromptLen(""), 0)
+
+  def testControlCharacters(self):
+    self.assertEqual(comp_ui._PromptLen("\xef"), 1)
+    self.assertEqual(comp_ui._PromptLen("\x03\x05"), 2)
 
 if __name__ == '__main__':
   unittest.main()
diff --git a/core/property_tests.py b/core/property_tests.py
new file mode 100755
index 0000000000..0e29e21fd1
--- /dev/null
+++ b/core/property_tests.py
@@ -0,0 +1,16 @@
+#!/usr/bin/env python2
+
+import unittest
+
+from hypothesis import given
+from hypothesis.strategies import text
+
+from comp_ui import _PromptLen
+
+class PromptTest(unittest.TestCase):
+    @given(text())
+    def testNeverPanics(self, s):
+        self.assertIs(_PromptLen(s) >= 0, True)
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/native/libc_test.py b/native/libc_test.py
index 8d1e860a29..2ecb7f5ac0 100755
--- a/native/libc_test.py
+++ b/native/libc_test.py
@@ -193,6 +193,7 @@ def testGetTerminalWidth(self):
   def testWcsWidth(self):
     self.assertEqual(1, libc.wcswidth("▶️"))
     self.assertEqual(28, libc.wcswidth("(osh) ~/.../unchanged/oil ▶️ "))
+    self.assertEqual(2, libc.wcswidth("→ "))
     self.assertRaises(UnicodeError, libc.wcswidth, "\xfe")
 
 if __name__ == '__main__':
diff --git a/osh/word.py b/osh/word.py
index e4cf1d7afe..291cb9228b 100644
--- a/osh/word.py
+++ b/osh/word.py
@@ -155,7 +155,7 @@ def LeftMostSpanForPart(part):
     return part.spids[0]
 
   elif isinstance(part, word_part__TildeSubPart):
-    return const.NO_INTEGER
+    return part.token.span_id
 
   elif isinstance(part, word_part__ArithSubPart):
     # begin, end
diff --git a/test/lint.sh b/test/lint.sh
index 7e4c370d32..fd786442be 100755
--- a/test/lint.sh
+++ b/test/lint.sh
@@ -90,8 +90,7 @@ bin-flake8() {
   if test -f "$ubuntu_flake8"; then
     $ubuntu_flake8 "$@"
   else
-    # Assume it's in $PATH, like on Travis.
-    flake8 "$@"
+    python2 -m flake8 "$@"
   fi
 }
 
diff --git a/vendor/typing.py b/vendor/typing.py
index b0fdb1c2d7..a9a700bf7d 100644
--- a/vendor/typing.py
+++ b/vendor/typing.py
@@ -10,6 +10,9 @@
 # if TYPE_CHECKING:
 #   NullFunc = Callable[[int, int], int]
 
+TypingMeta = None
+TypeVar = None
+_ForwardRef = None
 List = None
 Tuple = None
 Optional = None