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-- | Build a mapping so we can lookup a 'BrokenBlock' by its 'BlockId'
blocksToBlockEnv :: [BrokenBlock] -> BlockEnv BrokenBlock
-blocksToBlockEnv blocks = listToUFM $ map (\b -> (brokenBlockId b, b)) blocks
+blocksToBlockEnv blocks = mkBlockEnv $ map (\b -> (brokenBlockId b, b)) blocks