Presentation Compiler is now loaded with correct classloader

metals/src/main/scala/scala/meta/internal/metals/PresentationCompilerClassLoader.scala

@@ -9,7 +9,7 @@ package scala.meta.internal.metals
  * method signatures of the `PresentationCompiler` class.
  */
 class PresentationCompilerClassLoader(parent: ClassLoader)
-    extends ClassLoader(null) {
+    extends ClassLoader(ClassLoader.getSystemClassLoader().getParent()) {
   override def findClass(name: String): Class[_] = {
     val isShared =
       name.startsWith("org.eclipse.lsp4j") ||

tests/unit/src/test/scala/tests/ClassloaderModulesSupport.scala

@@ -0,0 +1,56 @@
+package tests
+
+import scala.meta.internal.metals.BuildInfo
+
+class ClassloaderModulesSupport
+    extends BaseLspSuite("classloader-modules-")
+    with TestHovers {
+
+  test("basic") {
+    cleanWorkspace()
+    for {
+      _ <- initialize(
+        s"""/metals.json
+           |{
+           |  "a": { "scalaVersion": "${BuildInfo.scala3}" },
+           |  "b": { "dependsOn": ["a"], "scalaVersion": "${BuildInfo.scala3}" }
+           |}
+           |
+           |/a/src/main/scala/a/A.scala
+           |package a
+           |
+           |import scala.quoted._
+           |
+           |object MacroImpl:
+           |  transparent inline def make = $${ makeImpl }
+           |
+           |  private def makeImpl(using Quotes): Expr[Unit] =
+           |    Class.forName("java.sql.Driver")
+           |    '{()}
+           |
+           |/b/src/main/scala/b/B.scala
+           |package b
+           |
+           |object B:
+           |  a.MacroImpl.make
+           |""".stripMargin
+      )
+      _ <- server.didOpen("a/src/main/scala/a/A.scala")
+      _ <- server.didOpen("b/src/main/scala/b/B.scala")
+      _ = assertNoDiagnostics()
+      _ <- server.assertHover(
+        "b/src/main/scala/b/B.scala",
+        """
+          |/b/src/main/scala/b/B.scala
+          |package b
+          |
+          |object B:
+          |  a.MacroImpl.ma@@ke
+          |""".stripMargin,
+        """|
+           |inline transparent def make: Unit
+           |""".stripMargin.hover,
+      )
+    } yield ()
+  }
+}