diff --git a/loopy/transform/loop_fusion.py b/loopy/transform/loop_fusion.py
index b86be517f..fcd4ab50b 100644
--- a/loopy/transform/loop_fusion.py
+++ b/loopy/transform/loop_fusion.py
@@ -753,24 +753,26 @@ def get_kennedy_unweighted_fusion_candidates(
     # {{{ sanitary checks
 
     _nest_tree_id_to_candidate = {}
+    _fusable_candidates = set()
 
     for iname in candidates:
         loop_nest_tree_node_id = iname_to_tree_node_id[iname]
         if loop_nest_tree_node_id not in _nest_tree_id_to_candidate:
             _nest_tree_id_to_candidate[loop_nest_tree_node_id] = iname
+            _fusable_candidates.add(iname)
         else:
             conflict_iname = _nest_tree_id_to_candidate[loop_nest_tree_node_id]
-            raise LoopyError(f"'{iname}' and '{conflict_iname}' "
-                             "cannot fused be fused as they can be nested "
-                             "within one another.")
+            from warnings import warn
+            warn(f"'{iname}' and '{conflict_iname}' "
+                 "cannot be fused as they can be nested within one another.")
 
-    for iname in candidates:
+    for iname in _fusable_candidates:
         outer_loops = reduce(frozenset.union,
                              tree.ancestors(iname_to_tree_node_id[iname]),
                              frozenset())
-        if outer_loops & candidates:
+        if outer_loops & _fusable_candidates:
             raise LoopyError(f"Cannot fuse '{iname}' with"
-                             f" '{outer_loops & candidates}' as they"
+                             f" '{outer_loops & _fusable_candidates}' as they"
                              " maybe nesting within one another.")
 
     del _nest_tree_id_to_candidate
@@ -782,7 +784,7 @@ def get_kennedy_unweighted_fusion_candidates(
     just_outer_loop_nest = {tree.parent(iname_to_tree_node_id[iname]): set()
                             for iname in candidates}
 
-    for iname in candidates:
+    for iname in _fusable_candidates:
         just_outer_loop_nest[tree.parent(iname_to_tree_node_id[iname])].add(iname)
 
     for outer_inames, inames in just_outer_loop_nest.items():