Fix scaladoc TastyInspector regressions

Adds an inspectAllTastyFilesInContext method in scaladoc-only version of
TastyInspector.

sbt-test/sbt-dotty/scaladoc-regressions/build.sbt

@@ -0,0 +1,9 @@
+ThisBuild / scalaVersion := sys.props("plugin.scalaVersion")
+
+lazy val i20476 = project
+  .in(file("i20476"))
+  .enablePlugins(ScalaJSPlugin)
+
+lazy val i18231 = project
+  .in(file("i18231"))
+  .settings(scalacOptions += "-release:8")

sbt-test/sbt-dotty/scaladoc-regressions/i18231/src/main/scala/main.scala

@@ -0,0 +1,4 @@
+object Foo {
+    @Deprecated
+    def foo(): Unit = ???
+}

sbt-test/sbt-dotty/scaladoc-regressions/i20476/src/main/scala/main.scala

@@ -0,0 +1,5 @@
+package demo
+
+import scala.scalajs.js
+
+def bar: js.Promise[Int] = js.Promise.resolve(()).`then`(_ => 1)

sbt-test/sbt-dotty/scaladoc-regressions/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % sys.props("plugin.scalaJSVersion"))

sbt-test/sbt-dotty/scaladoc-regressions/test

@@ -0,0 +1,2 @@
+> i18231/doc
+> i20476/doc

scaladoc/src/dotty/tools/scaladoc/tasty/TastyParser.scala

@@ -160,7 +160,7 @@ object ScaladocTastyInspector:
       report.error("File extension is not `tasty` or `jar`: " + invalidPath)
 
     if tastyPaths.nonEmpty then
-      TastyInspector.inspectAllTastyFiles(tastyPaths, jarPaths, classpath)(inspector)
+      TastyInspector.inspectAllTastyFilesInContext(tastyPaths, jarPaths, classpath)(inspector)(using ctx.compilerContext)
 
     val all = inspector.topLevels.result()
     all.groupBy(_._1).map { case (pckName, members) =>

scaladoc/src/scala/tasty/inspector/TastyInspector.scala

@@ -1,5 +1,7 @@
 // Copy of tasty-inspector/src/scala/tasty/inspector/TastyInspector.scala
 // FIXME remove this copy of the file
+// Since copying, an inspectAllTastyFilesInContext ,ethod was added for scaladoc only
+// to fix regressions introduced by the switch from old to a new TastyInspector
 
 package scala.tasty.inspector
 
@@ -41,6 +43,32 @@ object TastyInspector:
   def inspectTastyFilesInJar(jar: String)(inspector: Inspector): Boolean =
     inspectAllTastyFiles(Nil, List(jar), Nil)(inspector)
 
+  private def checkFiles(tastyFiles: List[String], jars: List[String]): Unit =
+    def checkFile(fileName: String, ext: String): Unit =
+      val file = dotty.tools.io.Path(fileName)
+      if !file.ext.toLowerCase.equalsIgnoreCase(ext) then
+        throw new IllegalArgumentException(s"File extension is not `.$ext`: $file")
+      else if !file.exists then
+        throw new IllegalArgumentException(s"File not found: ${file.toAbsolute}")
+    tastyFiles.foreach(checkFile(_, "tasty"))
+    jars.foreach(checkFile(_, "jar"))
+
+  /**
+  * Added for Scaladoc-only.
+  * Meant to fix regressions introduces by the switch from old to new TastyInspector:
+  *  https://github.com/scala/scala3/issues/18231
+  *  https://github.com/scala/scala3/issues/20476
+  * Stable TastyInspector API does not support passing compiler context.
+  */
+  def inspectAllTastyFilesInContext(tastyFiles: List[String], jars: List[String], dependenciesClasspath: List[String])(inspector: Inspector)(using Context): Boolean =
+    checkFiles(tastyFiles, jars)
+    val classes = tastyFiles ::: jars
+    classes match
+      case Nil => true
+      case _ =>
+        val reporter = inspectorDriver(inspector).process(inspectorArgs(dependenciesClasspath, classes), summon[Context])
+        !reporter.hasErrors
+
   /** Load and process TASTy files using TASTy reflect
    *
    *  @param tastyFiles List of paths of `.tasty` files
@@ -50,14 +78,7 @@ object TastyInspector:
    *  @return boolean value indicating whether the process succeeded
    */
   def inspectAllTastyFiles(tastyFiles: List[String], jars: List[String], dependenciesClasspath: List[String])(inspector: Inspector): Boolean =
-    def checkFile(fileName: String, ext: String): Unit =
-      val file = dotty.tools.io.Path(fileName)
-      if !file.ext.toLowerCase.equalsIgnoreCase(ext) then
-        throw new IllegalArgumentException(s"File extension is not `.$ext`: $file")
-      else if !file.exists then
-        throw new IllegalArgumentException(s"File not found: ${file.toAbsolute}")
-    tastyFiles.foreach(checkFile(_, "tasty"))
-    jars.foreach(checkFile(_, "jar"))
+    checkFiles(tastyFiles, jars)
     val files = tastyFiles ::: jars
     inspectFiles(dependenciesClasspath, files)(inspector)