Index: lib2to3/tests/test_fixers.py
===================================================================
--- lib2to3/tests/test_fixers.py	(revision 61573)
+++ lib2to3/tests/test_fixers.py	(working copy)
@@ -2913,6 +2913,33 @@
         self.check(b, a)
 
 
+class Test_paren(FixerTestCase):
+    fixer = "paren"
+
+    def test_0(self):
+        b = """[i for i in 1, 2 ]"""
+        a = """[i for i in (1, 2) ]"""
+        self.check(b, a)
+
+    def test_preserve(self):
+        b = """[i for i  in     1, 2 ]"""
+        a = """[i for i  in     (1, 2) ]"""
+        self.check(b, a)
+
+    def test_1(self):
+        b = """[i for i in 1, 2, ]"""
+        a = """[i for i in (1, 2,) ]"""
+        self.check(b, a)
+
+    def test_unchanged_0(self):
+        s = """[i for i in (1, 2)]"""
+        self.unchanged(s)
+
+    def test_unchanged_1(self):
+        s = """[i for i in foo()]"""
+        self.unchanged(s)
+
+
 if __name__ == "__main__":
     import __main__
     support.run_all_tests(__main__)
Index: lib2to3/fixes/fix_paren.py
===================================================================
--- lib2to3/fixes/fix_paren.py	(revision 0)
+++ lib2to3/fixes/fix_paren.py	(revision 0)
@@ -0,0 +1,31 @@
+"""Fixer that addes parentheses where they are required
+
+This converts ``[x for x in 1, 2]`` to ``[x for x in (1, 2)]``."""
+
+# Local imports
+from . import basefix
+from .util import Name, ListComp, LParen, RParen
+
+class FixParen(basefix.BaseFix):
+    PATTERN = """
+        atom< '['
+            listmaker< any
+                comp_for<
+                    'for' any 'in'
+                    it=testlist_safe< any (',' any)+ [',']
+                        [comp_iter] >
+                >
+            >
+        ']' >
+    """
+
+    def transform(self, node, results):
+        it = results["it"]
+
+        prefix = it.get_prefix()
+        it.set_prefix("")
+        it.insert_child(0, LParen())
+        it.append_child(RParen())
+        it.set_prefix(prefix)
+
+        return node