diff --git a/src/code_complete_results.cc b/src/code_complete_results.cc
index ba159eb..fd9d4de 100644
--- a/src/code_complete_results.cc
+++ b/src/code_complete_results.cc
@@ -18,16 +18,31 @@ clangmm::CodeCompleteResults::CodeCompleteResults(CXTranslationUnit &cx_tu,
                                   files,
                                   1,
                                   clang_defaultCodeCompleteOptions()|CXCodeComplete_IncludeBriefComments);
-  if(cx_results!=NULL)
+  if(cx_results)
     clang_sortCodeCompletionResults(cx_results->Results, cx_results->NumResults);
 }
 
+clangmm::CodeCompleteResults::CodeCompleteResults(CodeCompleteResults &&rhs) : cx_results(rhs.cx_results) {
+  rhs.cx_results = nullptr;
+}
+
+clangmm::CodeCompleteResults &clangmm::CodeCompleteResults::operator=(CodeCompleteResults &&rhs) {
+  if(this!=&rhs) {
+    if(cx_results)
+      clang_disposeCodeCompleteResults(cx_results);
+    cx_results=rhs.cx_results;
+    rhs.cx_results=nullptr;
+  }
+  return *this;
+}
+
 clangmm::CodeCompleteResults::~CodeCompleteResults() {
-  clang_disposeCodeCompleteResults(cx_results);
+  if(cx_results)
+    clang_disposeCodeCompleteResults(cx_results);
 }
 
 unsigned clangmm::CodeCompleteResults::size() const {
-  if(cx_results==NULL)
+  if(!cx_results)
     return 0;
   return cx_results->NumResults;
 }
@@ -37,5 +52,7 @@ clangmm::CompletionString clangmm::CodeCompleteResults::get(unsigned i) const {
 }
 
 std::string clangmm::CodeCompleteResults::get_usr() const {
+  if(!cx_results)
+    return std::string();
   return to_string(clang_codeCompleteGetContainerUSR(cx_results));
 }
diff --git a/src/code_complete_results.h b/src/code_complete_results.h
index 980d79b..05400c5 100644
--- a/src/code_complete_results.h
+++ b/src/code_complete_results.h
@@ -12,9 +12,10 @@ namespace clangmm {
     CodeCompleteResults(CXTranslationUnit &cx_tu, const std::string &buffer,
                         unsigned line_num, unsigned column);
   public:
-    CodeCompleteResults(CodeCompleteResults &&rhs) : cx_results(rhs.cx_results) {
-      rhs.cx_results = nullptr;
-    }
+    CodeCompleteResults(CodeCompleteResults &) = delete;
+    CodeCompleteResults(CodeCompleteResults &&rhs);
+    CodeCompleteResults &operator=(const CodeCompleteResults &rhs) = delete;
+    CodeCompleteResults &operator=(CodeCompleteResults &&rhs);
     ~CodeCompleteResults();
     CompletionString get(unsigned index) const;
     unsigned size() const;