Support copyToDir for tests that mutate original source

Author: felixmulder

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -20,8 +20,7 @@ class CompilationTests extends ParallelTesting {
 
   @Test def compilePosMixedFlags: Unit = {
     compileFile("../tests/pos/nullarify.scala", defaultOptions.and("-Ycheck:nullarify")) +
-    // this guy sucks, he changes the sourcefile itself:
-    // compileFile("../tests/pos-scala2/rewrites.scala", scala2Mode.and("-rewrite")) +
+    compileFile("../tests/pos-scala2/rewrites.scala", scala2Mode.and("-rewrite")).copyToTarget() +
     compileFile("../tests/pos-special/t8146a.scala", allowDeepSubtypes) +
     compileFile("../tests/pos-special/utf8encoded.scala", explicitUTF8) +
     compileFile("../tests/pos-special/utf16encoded.scala", explicitUTF16) +

compiler/test/dotty/tools/dotc/ParallelTesting.scala

@@ -479,6 +479,23 @@ trait ParallelTesting {
       this
     }
 
+    private def copyToDir(dir: JFile, file: JFile): JFile = {
+      val target = Paths.get(dir.getAbsolutePath, file.getName)
+      Files.copy(file.toPath, target, REPLACE_EXISTING)
+      if (file.isDirectory) file.listFiles.map(copyToDir(target.toFile, _))
+      target.toFile
+    }
+
+    def copyToTarget(): CompilationTest = new CompilationTest (
+      targets.map {
+        case target @ ConcurrentCompilationTarget(files, _, outDir) =>
+          target.copy(files = files.map(copyToDir(outDir,_)))
+        case target @ SeparateCompilationTarget(dir, _, outDir) =>
+          target.copy(dir = copyToDir(outDir, dir))
+      },
+      times, shouldDelete, threadLimit
+    )
+
     def times(i: Int): CompilationTest =
       new CompilationTest(targets, i, shouldDelete, threadLimit)
 
@@ -521,12 +538,6 @@ trait ParallelTesting {
     targetDir
   }
 
-  private def copyToDir(dir: JFile, file: JFile): Unit = {
-    val target = Paths.get(dir.getAbsolutePath, file.getName)
-    Files.copy(file.toPath, target, REPLACE_EXISTING)
-    if (file.isDirectory) file.listFiles.map(copyToDir(target.toFile, _))
-  }
-
   private def requirements(f: String, sourceDir: JFile, outDir: String): Unit = {
     require(sourceDir.isDirectory && sourceDir.exists, "passed non-directory to `compileFilesInDir`")
     require(outDir.last == '/', "please specify an `outDir` with a trailing slash")