Reflow hugging more aggressively

add_trailing_comma.py

@@ -271,7 +271,7 @@ def _fix_brace(fix_data, add_comma, tokens):
             # Don't unhug single element things with a multi-line component
             # inside.
             not fix_data.multi_arg and
-            hug_open and
+            tokens[first_brace + 1].src in START_BRACES and
             tokens[last_brace - 1].src in END_BRACES or
             # Don't unhug when containing a single token (such as a triple
             # quoted string).

tests/add_trailing_comma_test.py

@@ -594,6 +594,17 @@ def test_noop_unhugs(src):
             '    )\n'
             ']',
         ),
+        pytest.param(
+            'x = [x\n'
+            '     for x in y()]\n',
+
+            'x = [\n'
+            '    x\n'
+            '    for x in y()\n'
+            ']\n',
+
+            id='#42: listcomp unhug ends in brace',
+        ),
     ),
 )
 def test_fix_unhugs(src, expected):