diff --git a/sphinx/directives/other.py b/sphinx/directives/other.py
index d39a338d5..f59a29e14 100644
--- a/sphinx/directives/other.py
+++ b/sphinx/directives/other.py
@@ -73,8 +73,9 @@ class TocTree(Directive):
                     entries.append((title, ref))
                 elif docname not in env.found_docs:
                     ret.append(self.state.document.reporter.warning(
-                        'toctree references unknown document %r' % docname,
-                        line=self.lineno))
+                        'toctree contains reference to nonexisting '
+                        'document %r' % docname, line=self.lineno))
+                    env.note_reread()
                 else:
                     entries.append((title, docname))
                     includefiles.append(docname)