diff --git a/src/dotty/tools/dotc/Run.scala b/src/dotty/tools/dotc/Run.scala
index cc9b8db3a025..df7f433f9bcd 100644
--- a/src/dotty/tools/dotc/Run.scala
+++ b/src/dotty/tools/dotc/Run.scala
@@ -6,7 +6,8 @@ import Contexts._, Periods._, Symbols._
 import io.PlainFile
 import util.{SourceFile, NoSource, Stats, SimpleMap}
 import reporting.Reporter
-import java.io.FileWriter
+import java.io.{BufferedWriter, OutputStreamWriter}
+import scala.reflect.io.VirtualFile
 
 class Run(comp: Compiler)(implicit ctx: Context) {
 
@@ -21,8 +22,12 @@ class Run(comp: Compiler)(implicit ctx: Context) {
     }
   }
 
-  def compile(fileNames: List[String]): Unit = Stats.monitorHeartBeat {
+  def compile(fileNames: List[String]): Unit = {
     val sources = fileNames map getSource
+    compileSources(sources)
+  }
+
+  def compileSources(sources: List[SourceFile]) = Stats.monitorHeartBeat {
     if (sources forall (_.exists)) {
       units = sources map (new CompilationUnit(_))
       for (phase <- ctx.allPhases)
@@ -31,12 +36,11 @@ class Run(comp: Compiler)(implicit ctx: Context) {
   }
 
   def compile(sourceCode: String): Unit = {
-    val tmpFile = java.io.File.createTempFile("dotty-source-tmp", ".scala")
-    tmpFile.createNewFile()
-    val writer = new FileWriter(tmpFile)
+    val virtualFile = new VirtualFile(sourceCode) // use source code as name as it's used for equals
+    val writer = new BufferedWriter(new OutputStreamWriter(virtualFile.output, "UTF-8")) // buffering is still advised by javadoc
     writer.write(sourceCode)
     writer.close()
-    compile(List(tmpFile.getAbsolutePath))
+    compileSources(List(new SourceFile(virtualFile)))
   }
 
   /** Print summary; return # of errors encountered */