This will actually trigger all the 2.10.4 classes to be compiled again, since the analysis cache is not specific to scala version.

If we were using SBT's cross compiling features, this would fix it:

https://github.com/sbt/sbt/commit/e95b160cb564d9c060d102936724803e59c9767b

But we're not, so it doesn't.  However, it does give us a way to fix it ourselves, we should be able to set:

```scala
compileAnalysisFile := "inc_compile_" + scalaBinaryVersion.value
```