错误原因：
The Scala IDE tries to check if binary incompatible Scala libraries have been inadvertently mixed in a project’s classpath. It works by extracting, from the name of the jars, which major version of Scala it has been compiled against (assuming the Scala convention for publishing cross-compiled libraries, and further assuming that Scala minor releases are binary compatible). If the extracted Scala major version doesn’t match the one bundled with the Scala IDE, a problem is reported. This ad-hoc validation prevents one of the most common reason for compiler crashes and lack of intelligent behavior in the Scala IDE.
解决方法：
eclipse:
进入到windows->preferens->scala compiler->preference->Build manager->withVersionClasspathValidator 勾选去掉
右键点击项目 -》scala->Add Scala Libarary To Build Path即可
如果还有错，右击项目->Properties->scala compiler->Build Manager->withVersionClasspathValiadator 取消
ide:
If this check returns a false-negative, it can be disabled at the workspace level, or at the project level. The setting is withVersionClasspathValidator in the Scala → Compiler → Build Manager preference section.