diff --git a/jedi/cache.py b/jedi/cache.py
index d815f43a..24959f19 100644
--- a/jedi/cache.py
+++ b/jedi/cache.py
@@ -101,6 +101,9 @@ def cache_call_signatures(source, user_pos, stmt):
     """This function calculates the cache key."""
     index = user_pos[0] - 1
     lines = source.splitlines() or ['']
+    if source and source[-1] == '\n':
+        lines.append('')
+
     before_cursor = lines[index][:user_pos[1]]
     other_lines = lines[stmt.start_pos[0]:index]
     whole = '\n'.join(other_lines + [before_cursor])
diff --git a/test/test_cache.py b/test/test_cache.py
index bbceb985..4ad437b0 100644
--- a/test/test_cache.py
+++ b/test/test_cache.py
@@ -99,3 +99,8 @@ def test_cache_call_signatures():
     for i in range(3):
         check(8, 'int', 'boo')
         check(4, 'str', 'boo')
+
+
+def test_cache_line_split_issues():
+    """Should still work even if there's a newline."""
+    assert jedi.Script('int(\n').call_signatures()[0].name == 'int'