diff --git a/src/main/java/org/clarent/ivyidea/intellij/facet/IvyIdeaFacetDetector.java b/src/main/java/org/clarent/ivyidea/intellij/facet/IvyIdeaFacetDetector.java
index c13b5a2f..2358c4df 100644
--- a/src/main/java/org/clarent/ivyidea/intellij/facet/IvyIdeaFacetDetector.java
+++ b/src/main/java/org/clarent/ivyidea/intellij/facet/IvyIdeaFacetDetector.java
@@ -54,7 +54,7 @@ public ElementPattern<FileContent> createSuitableFilePattern() {
     }
 
     @Override
-    protected IvyIdeaFacetConfiguration createConfiguration(Collection<VirtualFile> files) {
+    protected IvyIdeaFacetConfiguration createConfiguration(Collection<? extends VirtualFile> files) {
         final IvyIdeaFacetConfiguration result = super.createConfiguration(files);
 
         if (!files.isEmpty()) {