Fix #1369 Print a newline for Unit values

Keeping only one newline for Unit values if there are more of them, in a command.

Author: benkobalog

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

@@ -70,17 +70,17 @@ private[repl] class Rendering(compiler: ReplCompiler,
     d.symbol.showUser
 
   /** Render value definition result */
-  def renderVal(d: Denotation)(implicit ctx: Context): Option[String] = {
+  def renderVal(d: Denotation)(implicit ctx: Context): String = {
     val dcl = d.symbol.showUser
 
     try {
       val resultValue =
         if (d.symbol.is(Flags.Lazy)) Some("<lazy>")
         else valueOf(d.symbol)
 
-      resultValue.map(value => s"$dcl = $value")
+      resultValue.fold("")(value => s"$dcl = $value")
     }
-    catch { case ex: InvocationTargetException => Some(renderError(ex)) }
+    catch { case ex: InvocationTargetException => renderError(ex) }
   }
 
   /** Render the stack trace of the underlying exception */

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

@@ -272,7 +272,7 @@ class ReplDriver(settings: Array[String],
       (
         typeAliases.map("// defined alias " + _.symbol.showUser) ++
         defs.map(rendering.renderMethod) ++
-        vals.map(rendering.renderVal).flatten
+        vals.map(rendering.renderVal).distinct
       ).foreach(str => out.println(SyntaxHighlighting(str)))
 
       state.copy(valIndex = state.valIndex - vals.filter(resAndUnit).length)

compiler/test-resources/repl/renderUnit

@@ -0,0 +1,4 @@
+scala>()
+
+scala>(); (); ()
+