http://www.haskell.org/pipermail/beginners/2011-March/006477.html The point is that the type of id has to be unified with the type of flip's (first) argument. flip :: (a -> b -> c) -> (b -> a -> c) id :: t -> t So we have to unify (a -&g…
启动项目报错 2018-02-26 17:09:51,535 ERROR [org.springframework.web.context.ContextLoader] - Context initialization failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'testTreeDao' defined in file [/Users/jds/Docu…