diff --git a/src/main/java/net/prominic/groovyls/providers/ReferenceProvider.java b/src/main/java/net/prominic/groovyls/providers/ReferenceProvider.java
index 8bafb8b5..b5cddedd 100644
--- a/src/main/java/net/prominic/groovyls/providers/ReferenceProvider.java
+++ b/src/main/java/net/prominic/groovyls/providers/ReferenceProvider.java
@@ -57,6 +57,8 @@ public CompletableFuture<List<? extends Location>> provideReferences(TextDocumen
 		List<ASTNode> references = GroovyASTUtils.getReferences(offsetNode, ast);
 		List<Location> locations = references.stream().map(node -> {
 			URI uri = ast.getURI(node);
+			if (uri == null)
+				return null;
 			return GroovyLanguageServerUtils.astNodeToLocation(node, uri);
 		}).filter(location -> location != null).collect(Collectors.toList());