fix call to get current source - fixes #24509

pkg/analysis_server/lib/src/services/completion/local_reference_contributor.dart

Index: pkg/analysis_server/lib/src/services/completion/local_reference_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/local_reference_contributor.dart b/pkg/analysis_server/lib/src/services/completion/local_reference_contributor.dart
index aa495cf0d7789245b05e368533b50d9dbe45ffc1..181f25959af3626ab9f51923283277af5e45d9be 100644
--- a/pkg/analysis_server/lib/src/services/completion/local_reference_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/local_reference_contributor.dart
@@ -356,7 +356,7 @@ class _LocalVisitor extends LocalDeclarationVisitor {
   _LocalVisitor(this.request, int offset, this.optype) : super(offset) {
     includeLocalInheritedTypes = !optype.inStaticMethodBody;
     if (request.replacementLength > 0) {
-      var contents = request.source.contents;
+      var contents = request.context.getContents(request.source);
       if (contents != null &&
           contents.data != null &&
           contents.data.startsWith('_', request.replacementOffset)) {