value | is not a member of String in Scala 2.10

It seems that the ParserApi implicit does not get invoked in Scala 2.10. The same source code compiles with Scala 2.11.

Sample build.sbt:

scalaVersion := "2.10.6"

libraryDependencies += "com.lihaoyi" %% "fastparse" % "0.3.4"

Hello.scala:

import fastparse.all._

object Hello {
  val t: P[String] = P("boo" | "bar")
}

sbt compile:

[info] Compiling 1 Scala source to /tmp/fp/target/scala-2.10/classes...
[error] /tmp/fp/Hello.scala:4: value | is not a member of String
[error]   val t: P[String] = P("boo" | "bar")
[error]                              ^
[error] one error found
[error] (compile:compile) Compilation failed
[error] Total time: 1 s, completed Dec 27, 2015 5:36:13 PM

[jrpelkonen]

I had the same issue. I fixed it by including macro paradise as it does not come with Scala 2.10. Basically, for Scala 2.10.6 this works, for other versions of scala 2.10, tweaks may be needed:

libraryDependencies ++= Seq(
  ...
  "com.lihaoyi" %% "fastparse" % "0.3.7",
  compilerPlugin("org.scalamacros" % "paradise" % "2.0.1" cross CrossVersion.full),
...

[lihaoyi]

Probably going to call this wontfix; most people should have upgraded to 2.11, and if you’re still on 2.10 upgrading is probably the higher priority