Dotty support

build.sbt

@@ -23,7 +23,19 @@ developers := List(
   )
 )
 
-crossScalaVersions := List("2.10.7", "2.11.12", "2.12.10", "2.13.1")
+crossScalaVersions := List(
+  "2.10.7", "2.11.12", "2.12.10", "2.13.1",
+  "0.22.0", "0.23.0", "0.24.0-RC1"
+)
+
+/** Add src/main/scala-{2|3} to Compile / unmanagedSourceDirectories */
+Compile / unmanagedSourceDirectories ++= {
+  val sourceDir = (Compile / sourceDirectory).value
+  CrossVersion.partialVersion(scalaVersion.value).map {
+    case (0 | 3, _) => sourceDir / "scala-3"
+    case (n, _) => sourceDir / s"scala-$n"
+  }
+}
 
 libraryDependencies ++= Seq(
   "org.scalatest" %% "scalatest-core" % "3.2.0-M4",
@@ -33,6 +45,7 @@ libraryDependencies ++= Seq(
   "org.scalatest" %% "scalatest-shouldmatchers" % "3.2.0-M4" % "test",
   "junit" % "junit" % "4.12"
 )
+Test / scalacOptions ++= (if (isDotty.value) Seq("-language:implicitConversions") else Nil)
 
 import scala.xml.{Node => XmlNode, NodeSeq => XmlNodeSeq, _}
 import scala.xml.transform.{RewriteRule, RuleTransformer}

project/plugins.sbt

@@ -3,3 +3,5 @@ addSbtPlugin("com.jsuereth" % "sbt-pgp" % "1.1.1")
 addSbtPlugin("com.geirsson" % "sbt-ci-release" % "1.2.2")
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-osgi" % "0.9.4")
+
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.4.1")

src/main/scala-2/org/scalatestplus/junit/VersionSpecificAssertionsForJUnit.scala

@@ -0,0 +1,16 @@
+package org.scalatestplus.junit
+
+import org.scalactic.{Prettifier, source}
+import org.scalatest.{Assertion, Assertions}
+
+trait VersionSpecificAssertionsForJUnit extends Assertions {
+  import scala.language.experimental.macros
+
+  override def assert(condition: Boolean)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assert
+
+  override def assert(condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assertWithClue
+
+  override def assume(condition: Boolean)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assume
+
+  override def assume(condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assumeWithClue
+}

src/main/scala-3/org/scalatestplus/junit/AssertionsForJUnitMacro.scala

@@ -0,0 +1,16 @@
+package org.scalatestplus.junit
+
+import org.scalactic.{Prettifier, source}
+import org.scalatest.Assertions
+import org.scalatest.AssertionsMacro.transform
+import org.scalatest.compatible.Assertion
+
+import scala.quoted.{Expr, QuoteContext}
+
+object AssertionsForJUnitMacro {
+  def assert(condition: Expr[Boolean], prettifier: Expr[Prettifier], pos: Expr[source.Position], clue: Expr[Any])(implicit qctx: QuoteContext): Expr[Assertion] =
+    transform('{AssertionsForJUnit.assertionsHelper.macroAssert}, condition, prettifier, pos, clue)
+
+  def assume(condition: Expr[Boolean], prettifier: Expr[Prettifier], pos: Expr[source.Position], clue: Expr[Any])(implicit qctx: QuoteContext): Expr[Assertion] =
+    transform('{AssertionsForJUnit.assertionsHelper.macroAssume}, condition, prettifier, pos, clue)
+}

src/main/scala-3/org/scalatestplus/junit/VersionSpecificAssertionsForJUnit.scala

@@ -0,0 +1,23 @@
+package org.scalatestplus.junit
+
+import org.scalactic.{Prettifier, source}
+import org.scalatest.{Assertions, AssertionsMacro}
+import org.scalatest.compatible.Assertion
+
+trait VersionSpecificAssertionsForJUnit extends Assertions {
+  // https://github.com/lampepfl/dotty/pull/8601#pullrequestreview-380646858
+  implicit object UseJUnitAssertions
+
+  inline def assert(inline condition: Boolean)(implicit prettifier: Prettifier, pos: source.Position, use: UseJUnitAssertions.type): Assertion =
+    ${ AssertionsForJUnitMacro.assert('{condition}, '{prettifier}, '{pos}, '{""}) }
+
+  inline def assert(inline condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: source.Position, use: UseJUnitAssertions.type): Assertion =
+    ${ AssertionsForJUnitMacro.assert('{condition}, '{prettifier}, '{pos}, '{clue}) }
+
+  inline def assume(inline condition: Boolean)(implicit prettifier: Prettifier, pos: source.Position, use: UseJUnitAssertions.type): Assertion =
+    ${ AssertionsForJUnitMacro.assume('{condition}, '{prettifier}, '{pos}, '{""}) }
+
+  inline def assume(inline condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: source.Position, use: UseJUnitAssertions.type): Assertion =
+    ${ AssertionsForJUnitMacro.assume('{condition}, '{prettifier}, '{pos}, '{clue}) }
+
+}

src/main/scala/org/scalatestplus/junit/AssertionsForJUnit.scala

@@ -95,7 +95,7 @@ import org.scalatest.exceptions.{StackDepthException, TestCanceledException}
  *
  * @author Bill Venners
  */
-trait AssertionsForJUnit extends Assertions {
+trait AssertionsForJUnit extends VersionSpecificAssertionsForJUnit {
 
   private[org] override def newAssertionFailedException(optionalMessage: Option[String], optionalCause: Option[Throwable], pos: source.Position, differences: scala.collection.immutable.IndexedSeq[String]): Throwable = {
     new JUnitTestFailedError(optionalMessage, optionalCause, pos, None)
@@ -116,16 +116,6 @@ trait AssertionsForJUnit extends Assertions {
     }
   }
 
-  import scala.language.experimental.macros
-
-  override def assert(condition: Boolean)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assert
-
-  override def assert(condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assertWithClue
-
-  override def assume(condition: Boolean)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assume
-
-  override def assume(condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: source.Position): Assertion = macro AssertionsForJUnitMacro.assumeWithClue
-
  /*
   private[scalatest] override def newAssertionFailedException(optionalMessage: Option[Any], optionalCause: Option[Throwable], stackDepth: Int): Throwable = {
 
@@ -222,6 +212,9 @@ object AssertionsForJUnit extends AssertionsForJUnit {
       Succeeded
     }
 
+    def macroAssert(bool: Bool, clue: Any, pos: source.Position): Assertion =
+      macroAssert(bool, clue, bool.prettifier, pos)
+
     /**
       * Assume that the passed in <code>Bool</code> is <code>true</code>, else throw <code>TestCanceledException</code>.
       *
@@ -236,6 +229,9 @@ object AssertionsForJUnit extends AssertionsForJUnit {
       }
       Succeeded
     }
+
+    def macroAssume(bool: Bool, clue: Any, pos: source.Position): Assertion =
+      macroAssume(bool, clue, bool.prettifier, pos)
   }
 
   /**

src/main/scala/org/scalatestplus/junit/JUnitHelper.scala

@@ -23,7 +23,7 @@ import org.scalatest.{Suite, TagAnnotation}
 private[junit] object JUnitHelper {
 
   def mergeMap[A, B](ms: List[Map[A, B]])(f: (B, B) => B): Map[A, B] =
-    (Map[A, B]() /: (for (m <- ms; kv <- m) yield kv)) { (a, kv) =>
+    (for (m <- ms; kv <- m) yield kv).foldLeft(Map[A, B]()) { (a, kv) =>
       a + (if (a.contains(kv._1)) kv._1 -> f(a(kv._1), kv._2) else kv)
     }
 
@@ -47,7 +47,7 @@ private[junit] object JUnitHelper {
     val decodedTestText = scala.reflect.NameTransformer.decode(testText)
     val formattedText =
       if (includeIcon) {
-        val testSucceededIcon = Resources.testSucceededIconChar
+        val testSucceededIcon = Resources.testSucceededIconChar()
         ("  " * (if (level == 0) 0 else (level - 1))) + Resources.iconPlusShortName(testSucceededIcon, decodedTestText)
       }
       else {
@@ -59,7 +59,7 @@ private[junit] object JUnitHelper {
   def checkForPublicNoArgConstructor(clazz: java.lang.Class[_]) = {
 
     try {
-      val constructor = clazz.getConstructor(new Array[java.lang.Class[T] forSome { type T }](0): _*)
+      val constructor = clazz.getConstructor(new Array[java.lang.Class[_]](0): _*)
 
       Modifier.isPublic(constructor.getModifiers)
     }

src/main/scala/org/scalatestplus/junit/JUnitWrapperSuite.scala

@@ -85,7 +85,7 @@ class JUnitWrapperSuite(junitClassName: String, loader: ClassLoader) extends Sui
    * @return number of expected test count
    */
   override def expectedTestCount(filter: Filter): Int = {
-    getRequest.getRunner.getDescription.testCount
+    getRequest().getRunner.getDescription.testCount
   }
 
   /**

src/main/scala/org/scalatestplus/junit/MyRunListener.scala

@@ -52,7 +52,7 @@ import exceptions._
         if (throwableOrNull != null)
           throwableOrNull.toString
         else
-          Resources.jUnitTestFailed
+          Resources.jUnitTestFailed()
 
       val formatter = getIndentedTextForTest(testName, 1, true)
       val payload = 

src/main/scala/org/scalatestplus/junit/RunNotifierReporter.scala

@@ -98,7 +98,7 @@ private[junit] class RunNotifierReporter(runNotifier: RunNotifier) extends Repor
             case None => null // Yuck. Not sure if the exception passed to new Failure can be null, but it could be given this code. Usually throwable would be defined.
           }
         val possiblyEmptyMessage = messageOrThrowablesDetailMessage(message, throwable)
-        val description = Description.createSuiteDescription(Resources.runAborted + " " + possiblyEmptyMessage)
+        val description = Description.createSuiteDescription(Resources.runAborted() + " " + possiblyEmptyMessage)
         runNotifier.fireTestFailure(new Failure(description, throwableOrNull)) // Best we can do in JUnit, as far as I know
         runNotifier.fireTestFinished(description)
 

src/test/scala/org/scalatestplus/junit/JUnitRunnerSuite.scala

@@ -105,15 +105,15 @@ package org.scalatestplus.junit {
     test("a test failure is reported due to an exception thrown from " +
          "beforeAll when JUnitRunner.run is called directly")
     {
-      val runNotifier =
-        new RunNotifier {
-          var methodInvocationCount = 0
-          var passed: Option[Failure] = None
-          override def fireTestFailure(failure: Failure): Unit = {
-            methodInvocationCount += 1
-            passed = Some(failure)
-          }
+      class MyRunNotifier extends RunNotifier {
+        var methodInvocationCount = 0
+        var passed: Option[Failure] = None
+        override def fireTestFailure(failure: Failure): Unit = {
+          methodInvocationCount += 1
+          passed = Some(failure)
         }
+      }
+      val runNotifier = new MyRunNotifier
 
       (new JUnitRunner(classOf[KerblooeySuite])).run(runNotifier)
 

src/test/scala/org/scalatestplus/junit/JUnitSuiteSuite.scala

@@ -15,15 +15,15 @@
  */
 package org.scalatestplus.junit {
 
-  import org.scalatest._
+import org.scalatest._
 import org.scalatest.events._
 
   // Put fixture suites in a subpackage, so they won't be discovered by
   // -m org.scalatest.junit when running the test target for this project.
   package helpers {
 
     import _root_.org.junit.Ignore
-import _root_.org.junit.Test
+    import _root_.org.junit.Test
 
     class HappySuite extends JUnitSuite {
 

src/test/scala/org/scalatestplus/junit/RunNotifierSuite.scala

@@ -33,16 +33,15 @@ class RunNotifierSuite extends funsuite.AnyFunSuite {
   val ordinal = new Ordinal(99)
 
   test("report(TestStarting) generates a fireTestStarted invocation") {
-
-    val runNotifier =
-      new RunNotifier {
-        var fireTestStartedInvocationCount = 0
-        var passedDesc: Option[Description] = None
-        override def fireTestStarted(description: Description): Unit = {
-          fireTestStartedInvocationCount += 1
-          passedDesc = Some(description)
-        }
+    class MyRunNotifier extends RunNotifier {
+      var fireTestStartedInvocationCount = 0
+      var passedDesc: Option[Description] = None
+      override def fireTestStarted(description: Description): Unit = {
+        fireTestStartedInvocationCount += 1
+        passedDesc = Some(description)
       }
+    }
+    val runNotifier = new MyRunNotifier
 
     import scala.language.reflectiveCalls
 
@@ -60,16 +59,15 @@ class RunNotifierSuite extends funsuite.AnyFunSuite {
   }
 
   test("report(TestFailed) generates a fireTestFailure invocation") {
-
-    val runNotifier =
-      new RunNotifier {
-        var methodInvocationCount = 0
-        var passed: Option[Failure] = None
-        override def fireTestFailure(failure: Failure): Unit = {
-          methodInvocationCount += 1
-          passed = Some(failure)
-        }
+    class MyRunNotifier extends RunNotifier {
+      var methodInvocationCount = 0
+      var passed: Option[Failure] = None
+      override def fireTestFailure(failure: Failure): Unit = {
+        methodInvocationCount += 1
+        passed = Some(failure)
       }
+    }
+    val runNotifier = new MyRunNotifier 
 
     val reporter = new RunNotifierReporter(runNotifier)
     val exception = new IllegalArgumentException
@@ -83,16 +81,15 @@ class RunNotifierSuite extends funsuite.AnyFunSuite {
   }
 
   test("report(TestSucceeded) generates a fireTestFinished invocation") {
-
-    val runNotifier =
-      new RunNotifier {
-        var methodInvocationCount = 0
-        var passed: Option[Description] = None
-        override def fireTestFinished(description: Description): Unit = {
-          methodInvocationCount += 1
-          passed = Some(description)
-        }
+    class MyRunNotifier extends RunNotifier {
+      var methodInvocationCount = 0
+      var passed: Option[Description] = None
+      override def fireTestFinished(description: Description): Unit = {
+        methodInvocationCount += 1
+        passed = Some(description)
       }
+    }
+    val runNotifier = new MyRunNotifier
 
     import scala.language.reflectiveCalls
 
@@ -104,16 +101,15 @@ class RunNotifierSuite extends funsuite.AnyFunSuite {
   }
 
   test("report(TestIgnored) generates a fireTestIgnored invocation") {
-
-    val runNotifier =
-      new RunNotifier {
-        var methodInvocationCount = 0
-        var passed: Option[Description] = None
-        override def fireTestIgnored(description: Description): Unit = {
-          methodInvocationCount += 1
-          passed = Some(description)
-        }
+    class MyRunNotifier extends RunNotifier {
+      var methodInvocationCount = 0
+      var passed: Option[Description] = None
+      override def fireTestIgnored(description: Description): Unit = {
+        methodInvocationCount += 1
+        passed = Some(description)
       }
+    }
+    val runNotifier = new MyRunNotifier
 
     import scala.language.reflectiveCalls
 
@@ -134,16 +130,15 @@ class RunNotifierSuite extends funsuite.AnyFunSuite {
 
   // fireTestFailure is the best we could do given the RunNotifier interface
   test("report(SuiteAborted) generates a fireTestFailure invocation") {
-
-    val runNotifier =
-      new RunNotifier {
-        var methodInvocationCount = 0
-        var passed: Option[Failure] = None
-        override def fireTestFailure(failure: Failure): Unit = {
-          methodInvocationCount += 1
-          passed = Some(failure)
-        }
+    class MyRunNotifier extends RunNotifier {
+      var methodInvocationCount = 0
+      var passed: Option[Failure] = None
+      override def fireTestFailure(failure: Failure): Unit = {
+        methodInvocationCount += 1
+        passed = Some(failure)
       }
+    }
+    val runNotifier = new MyRunNotifier
 
     import scala.language.reflectiveCalls
 
@@ -169,16 +164,15 @@ class RunNotifierSuite extends funsuite.AnyFunSuite {
 
   // fireTestFailure is the best we could do given the RunNotifier interface
   test("report(RunAborted) generates a fireTestFailure invocation") {
-
-    val runNotifier =
-      new RunNotifier {
-        var methodInvocationCount = 0
-        var passed: Option[Failure] = None
-        override def fireTestFailure(failure: Failure): Unit = {
-          methodInvocationCount += 1
-          passed = Some(failure)
-        }
+    class MyRunNotifier extends RunNotifier {
+      var methodInvocationCount = 0
+      var passed: Option[Failure] = None
+      override def fireTestFailure(failure: Failure): Unit = {
+        methodInvocationCount += 1
+        passed = Some(failure)
       }
+    }
+    val runNotifier = new MyRunNotifier
 
     val reporter = new RunNotifierReporter(runNotifier)
     val exception = new IllegalArgumentException