diff --git a/integration/src/test/scala-2.13+/CompilerMatcher.scala b/integration/src/test/scala-2.13+/CompilerMatcher.scala
index 5adf7520..4f845ce7 100644
--- a/integration/src/test/scala-2.13+/CompilerMatcher.scala
+++ b/integration/src/test/scala-2.13+/CompilerMatcher.scala
@@ -207,7 +207,7 @@ trait CompilerMatcher {
     file.delete
   }
 
-  def copyFileFromResource(source: String, dest: File) {
+  def copyFileFromResource(source: String, dest: File): Unit = {
     val in = getClass.getResourceAsStream(source)
     val reader = new java.io.BufferedReader(new java.io.InputStreamReader(in))
     val out = new java.io.PrintWriter(new java.io.FileWriter(dest))
diff --git a/integration/src/test/scala-2.13-/CompilerMatcher.scala b/integration/src/test/scala-2.13-/CompilerMatcher.scala
index ff9c2105..a46267b9 100644
--- a/integration/src/test/scala-2.13-/CompilerMatcher.scala
+++ b/integration/src/test/scala-2.13-/CompilerMatcher.scala
@@ -207,7 +207,7 @@ trait CompilerMatcher {
     file.delete
   }
 
-  def copyFileFromResource(source: String, dest: File) {
+  def copyFileFromResource(source: String, dest: File): Unit = {
     val in = getClass.getResourceAsStream(source)
     val reader = new java.io.BufferedReader(new java.io.InputStreamReader(in))
     val out = new java.io.PrintWriter(new java.io.FileWriter(dest))