REPL: display the compiler + Java version on startup

Co-authored-by: Seth Tisue <seth@tisue.net>

Author: dwijnand

compiler/src/dotty/tools/repl/JLineTerminal.scala

@@ -28,7 +28,7 @@ final class JLineTerminal extends java.io.Closeable {
   private def blue(str: String)(using Context) =
     if (ctx.settings.color.value != "never") Console.BLUE + str + Console.RESET
     else str
-  private def prompt(using Context)        = blue("scala> ")
+  private def prompt(using Context)        = blue("\nscala> ")
   private def newLinePrompt(using Context) = blue("     | ")
 
   /** Blockingly read line from `System.in`

compiler/src/dotty/tools/repl/ReplDriver.scala

@@ -5,6 +5,7 @@ import java.nio.charset.StandardCharsets
 
 import dotty.tools.dotc.ast.Trees._
 import dotty.tools.dotc.ast.{tpd, untpd}
+import dotty.tools.dotc.config.Properties.{javaVersion, javaVmName, simpleVersionString}
 import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Phases.{unfusedPhases, typerPhase}
 import dotty.tools.dotc.core.Denotations.Denotation
@@ -124,6 +125,10 @@ class ReplDriver(settings: Array[String],
   final def runUntilQuit(initialState: State = initialState): State = {
     val terminal = new JLineTerminal
 
+    out.println(
+      s"""Welcome to Scala $simpleVersionString ($javaVersion, Java $javaVmName).
+         |Type in expressions for evaluation. Or try :help.""".stripMargin)
+
     /** Blockingly read a line, getting back a parse result */
     def readLine(state: State): ParseResult = {
       val completer: Completer = { (_, line, candidates) =>
@@ -208,7 +213,7 @@ class ReplDriver(settings: Array[String],
   }
 
   private def interpret(res: ParseResult)(implicit state: State): State = {
-    val newState = res match {
+    res match {
       case parsed: Parsed if parsed.trees.nonEmpty =>
         compile(parsed, state)
 
@@ -225,11 +230,6 @@ class ReplDriver(settings: Array[String],
       case _ => // new line, empty tree
         state
     }
-    inContext(newState.context) {
-      if (!ctx.settings.XreplDisableDisplay.value)
-        out.println()
-      newState
-    }
   }
 
   /** Compile `parsed` trees and evolve `state` in accordance */