- = let Just node = lookupNode graph k
-
- -- delete conflict edges from other nodes to this one.
- graph1 = foldl' (\g k1 -> let Just g' = delConflict k1 k g in g') graph
+ | Just node <- lookupNode graph k
+ = let -- delete conflict edges from other nodes to this one.
+ graph1 = foldl' (\g k1 -> let Just g' = delConflict k1 k g in g') graph