diff --git a/jedi/parser/fast.py b/jedi/parser/fast.py
index 5d9ad2a4..7a33913d 100644
--- a/jedi/parser/fast.py
+++ b/jedi/parser/fast.py
@@ -133,7 +133,9 @@ class DiffParser(object):
         sm = difflib.SequenceMatcher(None, lines_old, lines_new)
         print(len(lines_old), line_length, lines_old, lines_new)
         for operation, i1, i2, j1, j2 in sm.get_opcodes():
-            debug.dbg('diff %s old[%s:%s] new[%s:%s]', operation, i1, i2, j1, j2)
+            debug.dbg('diff %s old[%s:%s] new[%s:%s]',
+                      operation, i1 + 1, i2, j1 + 1, j2)
+
             if j2 == line_length + int(self._added_newline):
                 # The empty part after the last newline is not relevant.
                 j2 -= 1
@@ -209,14 +211,19 @@ class DiffParser(object):
                 if nodes:
                     print('COPY', until_line_new, nodes)
                     self._copy_count += 1
+                    debug.dbg(
+                        'diff actuall copy %s to %s',
+                        nodes[0].start_pos[0],
+                        nodes[-1].end_pos[0]
+                    )
                     parent = self._insert_nodes(nodes)
                     self._update_names_dict(parent, nodes)
-                self._update_positions(nodes, line_offset)
+                    self._update_positions(nodes, line_offset)
                 # We have copied as much as possible (but definitely not too
-                # much). Therefore we escape, even if we're not at the end. The
-                # rest will be parsed.
-                # Might not reach until the end, because there's a statement
+                # much). Therefore we just parse the rest.
+                # We might not reach the end, because there's a statement
                 # that is not finished.
+                self._parse(until_line_new)
                 break
 
     def _get_old_line_stmt(self, old_line):
diff --git a/test/test_parser/test_diff_parser.py b/test/test_parser/test_diff_parser.py
index 6d364d50..a811befd 100644
--- a/test/test_parser/test_diff_parser.py
+++ b/test/test_parser/test_diff_parser.py
@@ -3,6 +3,7 @@ from textwrap import dedent
 import pytest
 
 import jedi
+from jedi import debug
 from jedi._compatibility import u
 from jedi.common import splitlines
 from jedi import cache
@@ -56,11 +57,13 @@ class Differ(object):
         self._first_use = True
 
     def initialize(self, source):
+        debug.dbg('differ: initialize', color='YELLOW')
         grammar = load_grammar()
         self.parser = ParserWithRecovery(grammar, source)
         return self.parser.module
 
     def parse(self, source, copies=0, parsers=0, allow_error_leafs=False):
+        debug.dbg('differ: parse copies=%s parsers=%s', copies, parsers, color='YELLOW')
         lines = splitlines(source, keepends=True)
         diff_parser = DiffParser(self.parser)
         new_module = diff_parser.update(lines)
@@ -182,11 +185,14 @@ def test_for_on_one_line(differ):
     src = dedent("""\
     def hi():
         for x in foo: pass
+        pass
 
         def nested():
             pass
     """)
-    differ.parse(src, parsers=1, copies=1)
+    # The second parser is for parsing the `def nested()` which is an `equal`
+    # operation in the SequenceMatcher.
+    differ.parse(src, parsers=2, copies=1)
 
 
 def test_open_parentheses(differ):