I\'ve created a play project with play 2.3.7
In the project directory, I ran activator and ran the eclipse command to generate eclipse project files.
eclipse
In Scala IDE 4.0.0 thinks there's errors in an out-of-the-box Play Framework 2.3.7 program you can find the solution (in brief: adding target/scala-2.11/twirl/main folder to the compilation path), give it a try.
target/scala-2.11/twirl/main