diff --git a/Lib/inspect.py b/Lib/inspect.py
index 5344893..8f79bc3 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -440,7 +440,9 @@
     if info: return info[0]
 
 def getsourcefile(object):
-    """Return the Python source file an object was defined in, if it exists."""
+    """Return the filename that can be used to locate an object's source.
+    Return None if no way can be identified to get the source.
+    """
     filename = getfile(object)
     if string.lower(filename[-4:]) in ('.pyc', '.pyo'):
         filename = filename[:-4] + '.py'
@@ -453,6 +455,9 @@
     # only return a non-existent filename if the module has a PEP 302 loader
     if hasattr(getmodule(object, filename), '__loader__'):
         return filename
+    # or it is in the linecache
+    if filename in linecache.cache:
+        return filename
 
 def getabsfile(object, _filename=None):
     """Return an absolute path to the source or compiled file for an object.
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index aaa15f8..08630a5 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -3,6 +3,7 @@
 import types
 import unittest
 import inspect
+import linecache
 import datetime
 from UserList import UserList
 from UserDict import UserDict
@@ -274,6 +275,11 @@
     def test_getsourcefile(self):
         self.assertEqual(inspect.getsourcefile(mod.spam), modfile)
         self.assertEqual(inspect.getsourcefile(git.abuse), modfile)
+        fn = "_non_existing_filename_used_for_sourcefile_test.py"
+        co = compile("None", fn, "exec")
+        self.assertEqual(inspect.getsourcefile(co), None)
+        linecache.cache[co.co_filename] = (1, None, "None", co.co_filename)
+        self.assertEqual(inspect.getsourcefile(co), fn)
 
     def test_getfile(self):
         self.assertEqual(inspect.getfile(mod.StupidGit), mod.__file__)
@@ -372,6 +378,15 @@
         self.assertRaises(IOError, inspect.getsource, unicodedata)
         self.assertRaises(IOError, inspect.findsource, unicodedata)
 
+    def test_findsource_code_in_linecache(self):
+        lines = ["x=1"]
+        co = compile(lines[0], "_dynamically_created_file", "exec")
+        self.assertRaises(IOError, inspect.findsource, co)
+        self.assertRaises(IOError, inspect.getsource, co)
+        linecache.cache[co.co_filename] = (1, None, lines, co.co_filename)
+        self.assertEquals(inspect.findsource(co), (lines,0))
+        self.assertEquals(inspect.getsource(co), lines[0])
+
 # Helper for testing classify_class_attrs.
 def attrs_wo_objs(cls):
     return [t[:3] for t in inspect.classify_class_attrs(cls)]
diff --git a/Misc/NEWS b/Misc/NEWS
index 152725a..21bbc3d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -26,6 +26,9 @@
 Library
 -------
 
+- Issue #8720: fix regression caused by fix for #4050 by making getsourcefile
+  smart enough to find source files in the linecache.
+
 - Issue #8986: math.erfc was incorrectly raising OverflowError for
   values between -27.3 and -30.0 on some platforms.