Index: Python/ast.c
===================================================================
--- Python/ast.c	(revision 56438)
+++ Python/ast.c	(working copy)
@@ -1243,9 +1243,23 @@
                     c->c_arena);
     case STRING: {
         PyObject *str = parsestrplus(c, n);
-        if (!str)
+        if (!str){
+            PyObject *type, *value, *tback, *errstr;
+            if (PyErr_ExceptionMatches(PyExc_UnicodeError)){
+                PyErr_Fetch(&type, &value, &tback);
+                errstr = ((PyUnicodeErrorObject *)value)->reason;
+                if (errstr){
+                    char *s = "";
+                    char buf[128];
+                    s = PyString_AsString(errstr);
+                    PyOS_snprintf(buf, sizeof(buf), "(unicode error) %s", s);
+                    ast_error(n, buf);
+                } else {
+                    ast_error(n, "(unicode error) unknown error");
+                }
+            }
             return NULL;
-
+        }
         PyArena_AddPyObject(c->c_arena, str);
         return Str(str, LINENO(n), n->n_col_offset, c->c_arena);
     }
Index: Lib/test/test_parser.py
===================================================================
--- Lib/test/test_parser.py	(revision 56438)
+++ Lib/test/test_parser.py	(working copy)
@@ -474,6 +474,12 @@
         st = parser.suite('1 = 3 + 4')
         self.assertRaises(SyntaxError, parser.compilest, st)
 
+    def test_compile_badunicode(self):
+        st = parser.suite('a = u"\U12345678"')
+        self.assertRaises(SyntaxError, parser.compilest, st)
+        st = parser.suite('a = u"\u1"')
+        self.assertRaises(SyntaxError, parser.compilest, st)
+
 def test_main():
     test_support.run_unittest(
         RoundtripLegalSyntaxTestCase,