diff --git a/key.core/src/main/java/de/uka/ilkd/key/parser/Location.java b/key.core/src/main/java/de/uka/ilkd/key/parser/Location.java
index 46b4b813bbf..83b5e395817 100644
--- a/key.core/src/main/java/de/uka/ilkd/key/parser/Location.java
+++ b/key.core/src/main/java/de/uka/ilkd/key/parser/Location.java
@@ -95,7 +95,8 @@ public int hashCode() {
     @Override
     public int compareTo(@NonNull Location o) {
         return Comparator
-                .<Location, URI>comparing(l -> l.fileUri)
-                .thenComparing(Location::getPosition).compare(this, o);
+                .<Location, URI>comparing(l -> l.fileUri, Comparator.nullsLast(Comparator.naturalOrder()))
+                .thenComparing(Location::getPosition, Comparator.nullsLast(Comparator.naturalOrder()))
+                .compare(this, o);
     }
 }