Driver: properly use root Context passed as argument

Also CompilerTest no longer runs the compiler with the context
DottyTest#ctx. Previously, we got away with this because
Compiler#process ignored it and created a new Context, but this commit
fixes this, and it is now very important that we use a different context
for every test we compile. Since DottyTest#ctx was the only part of
DottyTest we used, CompilerTest no longer extends DottyTest to make sure
that we do not use it accidentally. If we want to use DottyTest as a
base class for tests again, we will have to remove its implicit Context
field first.

Also do not try to initialize the definitions in the context used by
partest, this is not necessary.

Author: smarter

src/dotty/tools/dotc/Driver.scala

@@ -33,12 +33,10 @@ abstract class Driver extends DotClass {
   protected def sourcesRequired = true
 
   def setup(args: Array[String], rootCtx: Context): (List[String], Context) = {
-    val summary = CompilerCommand.distill(args)(rootCtx)
-    // FIXME: We should reuse rootCtx instead of creating newCtx, but this
-    // makes some tests fail with "denotation module _root_ invalid in run 2."
-    val newCtx = initCtx.setCompilerCallback(rootCtx.compilerCallback)
-    implicit val ctx: Context = newCtx.fresh.setSettings(summary.sstate)
-    val fileNames = CompilerCommand.checkUsage(summary, sourcesRequired)
+    val ctx = rootCtx.fresh
+    val summary = CompilerCommand.distill(args)(ctx)
+    ctx.setSettings(summary.sstate)
+    val fileNames = CompilerCommand.checkUsage(summary, sourcesRequired)(ctx)
     (fileNames, ctx)
   }
 

test/dotty/partest/DPDirectCompiler.scala

@@ -5,7 +5,7 @@ import scala.tools.partest.{ TestState, nest }
 import java.io.{ File, PrintWriter, FileWriter }
 
 
-/* NOTE: Adapted from partest.DirectCompiler and DottyTest */
+/* NOTE: Adapted from partest.DirectCompiler */
 class DPDirectCompiler(runner: DPTestRunner) extends nest.DirectCompiler(runner) {
 
   override def compile(opts0: List[String], sources: List[File]): TestState = {
@@ -15,9 +15,7 @@ class DPDirectCompiler(runner: DPTestRunner) extends nest.DirectCompiler(runner)
 
     implicit val ctx: dotty.tools.dotc.core.Contexts.Context = {
       val base = new dotty.tools.dotc.core.Contexts.ContextBase
-      val ctx = base.initialCtx.fresh
-      base.definitions.init(ctx)
-      ctx
+      base.initialCtx.fresh
     }
 
     try {

test/test/CompilerTest.scala

@@ -33,7 +33,7 @@ import org.junit.Test
   *        object Test { def main(args: Array[String]): Unit = ... }
   *        Classpath jars can be added to partestDeps in the sbt Build.scala.
   */
-abstract class CompilerTest extends DottyTest {
+abstract class CompilerTest {
 
   /** Override with output dir of test so it can be patched. Partest expects
     * classes to be in partest-generated/[kind]/[testname]-[kind].obj/ */
@@ -181,7 +181,7 @@ abstract class CompilerTest extends DottyTest {
   private def compileArgs(args: Array[String], xerrors: Int = 0)(implicit defaultOptions: List[String]): Unit = {
     val allArgs = args ++ defaultOptions
     val processor = if (allArgs.exists(_.startsWith("#"))) Bench else Main
-    val nerrors = processor.process(allArgs, ctx).errorCount
+    val nerrors = processor.process(allArgs).errorCount
     assert(nerrors == xerrors, s"Wrong # of errors. Expected: $xerrors, found: $nerrors")
   }