Alternative fix

Author: liufengyun

compiler/src/dotty/tools/dotc/classpath/ClassPath.scala

@@ -24,7 +24,7 @@ trait SourceFileEntry extends ClassRepresentation {
 
 case class PackageName(dottedString: String) {
   def isRoot: Boolean = dottedString.isEmpty
-  val dirPathTrailingSlash: String = FileUtils.dirPathInArchive(dottedString) + "/"
+  val dirPathTrailingSlash: String = FileUtils.dirPath(dottedString) + JFile.separatorChar
 
   def entryName(entry: String): String = {
     if (isRoot) entry else {

compiler/src/dotty/tools/dotc/classpath/FileUtils.scala

@@ -42,10 +42,9 @@ object FileUtils {
     else if (endsJava(fileName)) stripJavaExtension(fileName)
     else throw new FatalError("Unexpected source file ending: " + fileName)
 
+  /** Returns the relative directory path with `/` as separator */
   def dirPath(forPackage: String): String = forPackage.replace('.', JFile.separatorChar)
 
-  def dirPathInArchive(forPackage: String): String = forPackage.replace('.', '/')
-
   def endsClass(fileName: String): Boolean =
     fileName.length > 6 && fileName.substring(fileName.length - 6) == ".class"
 

compiler/src/dotty/tools/io/ZipArchive.scala

@@ -38,12 +38,12 @@ object ZipArchive {
   private def dirName(path: String)  = splitPath(path, front = true)
   private def baseName(path: String) = splitPath(path, front = false)
   private def splitPath(path0: String, front: Boolean): String = {
-    val isDir = path0.charAt(path0.length - 1) == '/'
+    val isDir = path0.charAt(path0.length - 1) == JFile.separatorChar
     val path  = if (isDir) path0.substring(0, path0.length - 1) else path0
-    val idx   = path.lastIndexOf('/')
+    val idx   = path.lastIndexOf(JFile.separatorChar)
 
     if (idx < 0)
-      if (front) "/"
+      if (front) JFile.separator
       else path
     else
       if (front) path.substring(0, idx + 1)