community-build: spray-json-shapeless failing in 2.12.x build

depends on shapeless which is currently broken in 2.12.x, but the failure can be seen by running the build against 2.12.1

at e.g. https://scala-ci.typesafe.com/job/scala-2.12.x-integrate-community-build/1258/consoleFull we see:

[spray-json-shapeless] [info] Compiling 3 Scala sources to /Users/tisue/community-builds.212/target-0.9.7-RC1/project-builds/spray-json-shapeless-fd6c394665ddf27a110c9db00c2144135b430073/target/scala-2.12/test-classes...
[spray-json-shapeless] [error] /Users/tisue/community-builds.212/target-0.9.7-RC1/project-builds/spray-json-shapeless-fd6c394665ddf27a110c9db00c2144135b430073/src/test/scala/fommil/sjs/FamilyFormatsSpec.scala:329: could not find implicit value for evidence parameter of type spray.json.JsonFormat[fommil.sjs.ExampleAst.TokenTree]
[spray-json-shapeless] [error]     roundtrip(SpecialToken: TokenTree, """{"type":"SpecialToken"}""")
[spray-json-shapeless] [error]              ^
[spray-json-shapeless] [error] one error found

@fommil can you help with this? it isn’t obvious to me what’s going on here.