Migrate semanticdb to explicit nulls

semanticdb.diff

diff --git a/src/main/scala/dotty/semanticdb/SourceFile.scala b/src/main/scala/dotty/semanticdb/SourceFile.scala
index c53579b..34560bc 100644
--- a/src/main/scala/dotty/semanticdb/SourceFile.scala
+++ b/src/main/scala/dotty/semanticdb/SourceFile.scala
@@ -68,4 +68,4 @@ class SourceFile(path: java.nio.file.Path) {
       }
       return previous
     }
-}
\ No newline at end of file
+}
diff --git a/src/main/scala/dotty/semanticdb/Utils.scala b/src/main/scala/dotty/semanticdb/Utils.scala
index 0bb6fda..ba9e431 100644
--- a/src/main/scala/dotty/semanticdb/Utils.scala
+++ b/src/main/scala/dotty/semanticdb/Utils.scala
@@ -28,7 +28,7 @@ object Utils {
   /** List all tasty files occuring in the folder f or one of its subfolders */
   def recursiveListFiles(f: File, prefix : String = ""): Array[File] = {
     val pattern = (".*" + prefix + ".*\\.tasty").r
-    val files = f.listFiles
+    val files = f.listFiles.map(_.nn)
     val folders = files.filter(_.isDirectory)
     val tastyfiles = files.filter(_.toPath.toString match {
       case pattern(x: _*) => true
@@ -78,4 +78,4 @@ object Utils {
     val (_, classnames) = tastyClasses.unzip
     return classnames
   }
-}
\ No newline at end of file
+}
diff --git a/src/test/scala/dotty/semanticdb/MD5.scala b/src/test/scala/dotty/semanticdb/MD5.scala
index 4cd0f50..4b14a2e 100644
--- a/src/test/scala/dotty/semanticdb/MD5.scala
+++ b/src/test/scala/dotty/semanticdb/MD5.scala
@@ -26,4 +26,4 @@ object MD5 {
     }
     new String(hexChars)
   }
-}
\ No newline at end of file
+}
diff --git a/src/test/scala/dotty/semanticdb/Semanticdbs.scala b/src/test/scala/dotty/semanticdb/Semanticdbs.scala
index 7626732..3995d13 100644
--- a/src/test/scala/dotty/semanticdb/Semanticdbs.scala
+++ b/src/test/scala/dotty/semanticdb/Semanticdbs.scala
@@ -18,7 +18,7 @@ object Semanticdbs {
    */
   class Loader(sourceroot: Path, classpath: List[Path]) {
     private val META_INF = Paths.get("META-INF", "semanticdb").resolve(buildSubFolder)
-    private val classLoader = new java.net.URLClassLoader(classpath.map(_.toUri.toURL).toArray)
+    private val classLoader = new java.net.URLClassLoader(classpath.map(_.toUri.toURL).toArray[java.net.URL | JavaNull])
     /** Returns a SemanticDB for a single Scala source file, if any. The path must be absolute. */
     def resolve(scalaAbsolutePath: Path): Option[s.TextDocument] = {
       val scalaRelativePath = sourceroot.relativize(scalaAbsolutePath)
diff --git a/src/test/scala/dotty/semanticdb/Tests.scala b/src/test/scala/dotty/semanticdb/Tests.scala
index 3ccafea..651147f 100644
--- a/src/test/scala/dotty/semanticdb/Tests.scala
+++ b/src/test/scala/dotty/semanticdb/Tests.scala
@@ -111,8 +111,8 @@ class Tests {
     val scalaFolderReg = """scala-(\d+)\.(\d+)""".r
     val (_, _, path) = files
       .collect(file =>
-        file.getName match {
-          case scalaFolderReg(major, minor) => (major, minor, file.getName)
+        file.nn.getName match {
+          case scalaFolderReg(major, minor) => (major, minor, file.nn.getName)
       })
       .max
     Paths.get(root, path, "test-classes")
@@ -156,7 +156,7 @@ class Tests {
   def assertNoDiff(obtained: String, expected: String): Unit = {
     if (obtained.isEmpty && !expected.isEmpty) fail("obtained empty output")
     def splitLines(string: String): java.util.List[String] =
-      string.trim.replace("\r\n", "\n").split("\n").toSeq.asJava
+      string.trim.replace("\r\n", "\n").split("\n").map(_.nn).toSeq.asJava
     val obtainedLines = splitLines(obtained)
     val b = splitLines(expected)
     val patch = difflib.DiffUtils.diff(obtainedLines, b)