Add support for the -with-compiler runner option

modules/cli/src/main/scala/scala/cli/commands/shared/SharedOptions.scala

@@ -144,6 +144,12 @@ final case class SharedOptions(
   @Tag(tags.implementation)
   @Hidden
     scalaLibrary: Option[Boolean] = None,
+  @Group("Scala")
+  @HelpMessage("Allows to include the Scala compiler artifacts on the classpath.")
+  @Tag(tags.must)
+  @Name("withScalaCompiler")
+  @Name("-with-compiler")
+    withCompiler: Option[Boolean] = None,
   @Group("Java")
   @HelpMessage("Do not add dependency to Scala Standard library. This is useful, when Scala CLI works with pure Java projects.")
   @Tag(tags.implementation)
@@ -276,6 +282,7 @@ final case class SharedOptions(
           .map(bo.MaybeScalaVersion(_)),
         scalaBinaryVersion = scalaBinaryVersion.map(_.trim).filter(_.nonEmpty),
         addScalaLibrary = scalaLibrary.orElse(java.map(!_)),
+        addScalaCompiler = withCompiler,
         generateSemanticDbs = semanticDb,
         scalacOptions = scalac
           .scalacOption

modules/cli/src/main/scala/scala/cli/exportCmd/Mill.scala

@@ -32,6 +32,7 @@ final case class Mill(
   private def scalaVersionSettings(options: BuildOptions, sources: Sources): MillProject = {
 
     val pureJava = !options.scalaOptions.addScalaLibrary.contains(true) &&
+      !options.scalaOptions.addScalaCompiler.contains(true) &&
       sources.paths.forall(_._1.last.endsWith(".java")) &&
       sources.inMemory.forall(_.generatedRelPath.last.endsWith(".java")) &&
       options.classPathOptions.extraDependencies.toSeq

modules/cli/src/main/scala/scala/cli/exportCmd/Sbt.scala

@@ -38,6 +38,7 @@ final case class Sbt(
   private def pureJavaSettings(options: BuildOptions, sources: Sources): SbtProject = {
 
     val pureJava = !options.scalaOptions.addScalaLibrary.contains(true) &&
+      !options.scalaOptions.addScalaCompiler.contains(true) &&
       sources.paths.forall(_._1.last.endsWith(".java")) &&
       sources.inMemory.forall(_.generatedRelPath.last.endsWith(".java")) &&
       options.classPathOptions.extraDependencies.toSeq

modules/integration/src/test/scala/scala/cli/integration/CompileTestDefinitions.scala

@@ -540,4 +540,32 @@ abstract class CompileTestDefinitions(val scalaVersionOpt: Option[String])
       expect(classFiles.contains(os.rel / "Hello.class"))
     }
   }
+
+  private def compilerArtifactName: String =
+    if (actualScalaVersion.startsWith("3")) "scala3-compiler" else "scala-compiler"
+
+  test(s"ensure the -with-compiler option adds $compilerArtifactName to the classpath") {
+    TestInputs(os.rel / "s.sc" -> """println("Hello")""")
+      .fromRoot { root =>
+        val compileRes = os.proc(
+          TestUtil.cli,
+          "compile",
+          "s.sc",
+          "--print-classpath",
+          extraOptions
+        )
+          .call(cwd = root)
+        expect(!compileRes.out.trim().contains(compilerArtifactName))
+        val compileWithCompilerRes = os.proc(
+          TestUtil.cli,
+          "compile",
+          "s.sc",
+          "-with-compiler",
+          "--print-classpath",
+          extraOptions
+        )
+          .call(cwd = root)
+        expect(compileWithCompilerRes.out.trim().contains(compilerArtifactName))
+      }
+  }
 }

modules/integration/src/test/scala/scala/cli/integration/RunScalacCompatTestDefinitions.scala

@@ -466,4 +466,29 @@ trait RunScalacCompatTestDefinitions { _: RunTestDefinitions =>
         }
     }
   }
+
+  if (actualScalaVersion.startsWith("3"))
+    test("ensure -with-compiler is supported for Scala 3") {
+      TestInputs(
+        os.rel / "s.sc" ->
+          "println(dotty.tools.dotc.config.Properties.simpleVersionString)"
+      )
+        .fromRoot { root =>
+          val res =
+            os.proc(TestUtil.cli, "-with-compiler", "s.sc", extraOptions)
+              .call(cwd = root)
+          expect(res.out.trim() == actualScalaVersion)
+        }
+    }
+
+  if (actualScalaVersion.startsWith("2.13"))
+    test("ensure -with-compiler is supported for Scala 2.13") {
+      TestInputs(os.rel / "s.sc" -> "println(scala.tools.nsc.Properties.versionString)")
+        .fromRoot { root =>
+          val res =
+            os.proc(TestUtil.cli, "-with-compiler", "s.sc", extraOptions)
+              .call(cwd = root)
+          expect(res.out.trim() == s"version $actualScalaVersion")
+        }
+    }
 }

modules/options/src/main/scala/scala/build/options/BuildOptions.scala

@@ -85,6 +85,19 @@ final case class BuildOptions(
     }
   }
 
+  private def scalaCompilerDependencies: Either[BuildException, Seq[AnyDependency]] = either {
+    value(scalaParams).toSeq.flatMap { sp =>
+      if (scalaOptions.addScalaCompiler.getOrElse(false))
+        Seq(
+          if (sp.scalaVersion.startsWith("3."))
+            dep"org.scala-lang::scala3-compiler::${sp.scalaVersion}"
+          else
+            dep"org.scala-lang:scala-compiler:${sp.scalaVersion}"
+        )
+      else Nil
+    }
+  }
+
   private def maybeJsDependencies: Either[BuildException, Seq[AnyDependency]] = either {
     if (platform.value == Platform.JS)
       value(scalaParams).toSeq.flatMap { scalaParams0 =>
@@ -103,6 +116,7 @@ final case class BuildOptions(
     value(maybeJsDependencies).map(Positioned.none(_)) ++
       value(maybeNativeDependencies).map(Positioned.none(_)) ++
       value(scalaLibraryDependencies).map(Positioned.none(_)) ++
+      value(scalaCompilerDependencies).map(Positioned.none(_)) ++
       classPathOptions.extraDependencies.toSeq
   }
 

modules/options/src/main/scala/scala/build/options/ScalaOptions.scala

@@ -8,6 +8,7 @@ final case class ScalaOptions(
   scalaVersion: Option[MaybeScalaVersion] = None,
   scalaBinaryVersion: Option[String] = None,
   addScalaLibrary: Option[Boolean] = None,
+  addScalaCompiler: Option[Boolean] = None,
   generateSemanticDbs: Option[Boolean] = None,
   scalacOptions: ShadowingSeq[Positioned[ScalacOpt]] = ShadowingSeq.empty,
   extraScalaVersions: Set[String] = Set.empty,

website/docs/reference/cli-options.md

@@ -1379,6 +1379,12 @@ Specify platform
 ### `--scala-library`
 
 [Internal]
+### `--with-compiler`
+
+Aliases: `-with-compiler`, `--with-scala-compiler`
+
+Allows to include the Scala compiler artifacts on the classpath.
+
 ### `--java`
 
 [Internal]

website/docs/reference/scala-command/cli-options.md

@@ -926,6 +926,14 @@ Specify platform
 
 `IMPLEMENTATION specific` per Scala Runner specification
 
+### `--with-compiler`
+
+Aliases: `-with-compiler`, `--with-scala-compiler`
+
+`MUST have` per Scala Runner specification
+
+Allows to include the Scala compiler artifacts on the classpath.
+
 ### `--java`
 
 `IMPLEMENTATION specific` per Scala Runner specification

website/docs/reference/scala-command/runner-specification.md

@@ -86,6 +86,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -591,6 +597,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -1100,6 +1112,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -1623,6 +1641,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -2184,6 +2208,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -2725,6 +2755,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -3276,6 +3312,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -3880,6 +3922,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path
@@ -4681,6 +4729,12 @@ Add a resource directory
 
 Aliases: `--resource-dir`
 
+**--with-compiler**
+
+Allows to include the Scala compiler artifacts on the classpath.
+
+Aliases: `-with-compiler` ,`--with-scala-compiler`
+
 **--compilation-output**
 
 Copy compilation results to output directory using either relative or absolute path