Incorrect Java version check

The dotty implementation of Properties.isJavaAtLeast is broken for Java
9 (Fixed in Scalac at scala/scala#5276, but
maybe we just shouldn't have a copy of Properties.scala in Dotty). The
test is useless now anyway since we only compile with 2.12 which
requires Java 8, so this code is never going to run on an older version
of the JVM.

Author: smarter

compiler/src/dotty/tools/dotc/config/CompilerCommand.scala

@@ -137,9 +137,6 @@ object CompilerCommand extends DotClass {
     else if (settings.version.value) {
       ctx.echo(versionMsg)
       Nil
-    } else if (!Properties.isJavaAtLeast("1.8")) {
-      ctx.error("Dotty requires Java 8 to run")
-      Nil
     }
     else if (shouldStopWithInfo) {
       ctx.echo(infoMessage)

compiler/src/dotty/tools/dotc/config/Properties.scala

@@ -131,19 +131,4 @@ trait PropertiesTrait {
   def versionMsg            = "Scala %s %s -- %s".format(propCategory, versionString, copyrightString)
   def scalaCmd              = if (isWin) "dotr.bat" else "dotr"
   def scalacCmd             = if (isWin) "dotc.bat" else "dotc"
-
-  /** Can the java version be determined to be at least as high as the argument?
-   *  Hard to properly future proof this but at the rate 1.7 is going we can leave
-   *  the issue for our cyborg grandchildren to solve.
-   */
-  def isJavaAtLeast(version: String) = {
-    val okVersions = version match {
-      case "1.5"    => List("1.5", "1.6", "1.7", "1.8")
-      case "1.6"    => List("1.6", "1.7", "1.8")
-      case "1.7"    => List("1.7", "1.8")
-      case "1.8"    => List("1.8")
-      case _        => Nil
-    }
-    okVersions exists (javaVersion startsWith _)
-  }
 }