[lldb][NFC] Add CompletionRequest::AppendEmptyArgument

This is the only legitimate use we currently have for modifying
a CompletionRequest. Add a utility function for this purpose
and remove the remaining setters which go against the idea of
having an immutable CompletionRequest.

llvm-svn: 372858

1 files changed, 1 insertions, 2 deletions

diff --git a/lldb/source/Commands/CommandObjectMultiword.cpp b/lldb/source/Commands/CommandObjectMultiword.cpp
index e06c733..c0f5d67 100644
--- a/lldb/source/Commands/CommandObjectMultiword.cpp
+++ b/lldb/source/Commands/CommandObjectMultiword.cpp
@@ -195,8 +195,7 @@ void CommandObjectMultiword::HandleCompletion(CompletionRequest &request) {
       if (cmd_obj != nullptr) {
         if (request.GetParsedLine().GetArgumentCount() != 1) {
           request.GetParsedLine().Shift();
-          request.SetCursorCharPosition(0);
-          request.GetParsedLine().AppendArgument(llvm::StringRef());
+          request.AppendEmptyArgument();
           cmd_obj->HandleCompletion(request);
         }
       }