diff -r 0e7fab504305 -r 1d824df4f2bd server/test/unittest_rql2sql.py
--- a/server/test/unittest_rql2sql.py	Fri Jul 17 16:48:43 2015 +0200
+++ b/server/test/unittest_rql2sql.py	Tue Jul 28 09:25:26 2015 +0200
@@ -396,13 +396,13 @@
 ORDER BY 1'''),
 
     # DISTINCT, can use relation under exists scope as principal
-    ('DISTINCT Any X,Y WHERE X name "CWGroup", Y eid IN(1, 2, 3), EXISTS(X read_permission Y)',
+    ('DISTINCT Any X,Y WHERE X name "CWGroup", X is CWEType, Y eid IN(1, 2, 3), EXISTS(X read_permission Y)',
      '''SELECT DISTINCT _X.cw_eid, rel_read_permission0.eid_to
 FROM cw_CWEType AS _X, read_permission_relation AS rel_read_permission0
 WHERE _X.cw_name=CWGroup AND rel_read_permission0.eid_to IN(1, 2, 3) AND EXISTS(SELECT 1 WHERE rel_read_permission0.eid_from=_X.cw_eid)'''),
 
     # no distinct, Y can't be invariant
-    ('Any X,Y WHERE X name "CWGroup", Y eid IN(1, 2, 3), EXISTS(X read_permission Y)',
+    ('Any X,Y WHERE X name "CWGroup", X is CWEType, Y eid IN(1, 2, 3), EXISTS(X read_permission Y)',
      '''SELECT _X.cw_eid, _Y.cw_eid
 FROM cw_CWEType AS _X, cw_CWGroup AS _Y
 WHERE _X.cw_name=CWGroup AND _Y.cw_eid IN(1, 2, 3) AND EXISTS(SELECT 1 FROM read_permission_relation AS rel_read_permission0 WHERE rel_read_permission0.eid_from=_X.cw_eid AND rel_read_permission0.eid_to=_Y.cw_eid)
@@ -412,7 +412,7 @@
 WHERE _X.cw_name=CWGroup AND _Y.cw_eid IN(1, 2, 3) AND EXISTS(SELECT 1 FROM read_permission_relation AS rel_read_permission0 WHERE rel_read_permission0.eid_from=_X.cw_eid AND rel_read_permission0.eid_to=_Y.cw_eid)'''),
 
     # DISTINCT but NEGED exists, can't be invariant
-    ('DISTINCT Any X,Y WHERE X name "CWGroup", Y eid IN(1, 2, 3), NOT EXISTS(X read_permission Y)',
+    ('DISTINCT Any X,Y WHERE X name "CWGroup", X is CWEType, Y eid IN(1, 2, 3), NOT EXISTS(X read_permission Y)',
      '''SELECT DISTINCT _X.cw_eid, _Y.cw_eid
 FROM cw_CWEType AS _X, cw_CWGroup AS _Y
 WHERE _X.cw_name=CWGroup AND _Y.cw_eid IN(1, 2, 3) AND NOT (EXISTS(SELECT 1 FROM read_permission_relation AS rel_read_permission0 WHERE rel_read_permission0.eid_from=_X.cw_eid AND rel_read_permission0.eid_to=_Y.cw_eid))
@@ -422,7 +422,7 @@
 WHERE _X.cw_name=CWGroup AND _Y.cw_eid IN(1, 2, 3) AND NOT (EXISTS(SELECT 1 FROM read_permission_relation AS rel_read_permission0 WHERE rel_read_permission0.eid_from=_X.cw_eid AND rel_read_permission0.eid_to=_Y.cw_eid))'''),
 
     # should generate the same query as above
-    ('DISTINCT Any X,Y WHERE X name "CWGroup", Y eid IN(1, 2, 3), NOT X read_permission Y',
+    ('DISTINCT Any X,Y WHERE X name "CWGroup", X is CWEType, Y eid IN(1, 2, 3), NOT X read_permission Y',
      '''SELECT DISTINCT _X.cw_eid, _Y.cw_eid
 FROM cw_CWEType AS _X, cw_CWGroup AS _Y
 WHERE _X.cw_name=CWGroup AND _Y.cw_eid IN(1, 2, 3) AND NOT (EXISTS(SELECT 1 FROM read_permission_relation AS rel_read_permission0 WHERE rel_read_permission0.eid_from=_X.cw_eid AND rel_read_permission0.eid_to=_Y.cw_eid))
@@ -432,7 +432,7 @@
 WHERE _X.cw_name=CWGroup AND _Y.cw_eid IN(1, 2, 3) AND NOT (EXISTS(SELECT 1 FROM read_permission_relation AS rel_read_permission0 WHERE rel_read_permission0.eid_from=_X.cw_eid AND rel_read_permission0.eid_to=_Y.cw_eid))'''),
 
     # neged relation, can't be inveriant
-    ('Any X,Y WHERE X name "CWGroup", Y eid IN(1, 2, 3), NOT X read_permission Y',
+    ('Any X,Y WHERE X name "CWGroup", X is CWEType, Y eid IN(1, 2, 3), NOT X read_permission Y',
      '''SELECT _X.cw_eid, _Y.cw_eid
 FROM cw_CWEType AS _X, cw_CWGroup AS _Y
 WHERE _X.cw_name=CWGroup AND _Y.cw_eid IN(1, 2, 3) AND NOT (EXISTS(SELECT 1 FROM read_permission_relation AS rel_read_permission0 WHERE rel_read_permission0.eid_from=_X.cw_eid AND rel_read_permission0.eid_to=_Y.cw_eid))