Summary:
Makes the code a bit safer in the unlikely situation that we don't get a ClangUserExpression
when doing code completion.
Reviewers: aprantl, jingham
Reviewed By: aprantl
Subscribers: labath, jdoerfert, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D59359
llvm-svn: 356174