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..4a82961a52f 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
@@ -94,8 +94,7 @@ public int hashCode() {
 
     @Override
     public int compareTo(@NonNull Location o) {
-        return Comparator
-                .<Location, URI>comparing(l -> l.fileUri)
-                .thenComparing(Location::getPosition).compare(this, o);
+        return Comparator.<Location, URI>comparing(l -> l.fileUri, Comparator.nullsLast(Comparator.naturalOrder()))
+                .thenComparing(Location::getPosition, Comparator.nullsLast(Comparator.naturalOrder())).compare(this, o);
     }
 }