commit 8ea4f8e13710fe1536a0d1647cf48193bd815ab2
author Chih-Hung Hsieh <chh@google.com> Tue May 23 16:19:04 2017 +0000
committer Yi Kong <yikong@google.com> Tue May 30 10:38:03 2017 -0700
tree bef3dcd2fb03a5a6235dbba7cb2a13dc640a4f90
parent 09103fe1ea8f23d0556ea265718af0f9458c413b

[clang-tidy] Do not dereference a null BaseType

Check BaseType before dereference.
Simplified test case is derived from Android Open Source code.

Differential Revision: https://reviews.llvm.org/D33430

Change-Id: I06e5c33489f48de29e7873718223c444561a940c
git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@303645 91177308-0d34-0410-b5e6-96231b3b80d8

clang-tidy/misc/ForwardingReferenceOverloadCheck.cpp

diff --git a/clang-tidy/misc/ForwardingReferenceOverloadCheck.cpp b/clang-tidy/misc/ForwardingReferenceOverloadCheck.cpp
index 550c116..1e81a1a 100644
--- a/clang-tidy/misc/ForwardingReferenceOverloadCheck.cpp
+++ b/clang-tidy/misc/ForwardingReferenceOverloadCheck.cpp
@@ -40,6 +40,8 @@
   if (const auto *Dependent = BaseType->getAs<DependentNameType>()) {

     BaseType = Dependent->getQualifier()->getAsType();

   }

+  if (!BaseType)

+    return false;

   if (CheckTemplate(BaseType->getAs<TemplateSpecializationType>())) {

     return true; // Case: enable_if_t< >.

   } else if (const auto *Elaborated = BaseType->getAs<ElaboratedType>()) {

test/clang-tidy/misc-forwarding-reference-overload.cpp

diff --git a/test/clang-tidy/misc-forwarding-reference-overload.cpp b/test/clang-tidy/misc-forwarding-reference-overload.cpp
index 621654f..80000b7 100644
--- a/test/clang-tidy/misc-forwarding-reference-overload.cpp
+++ b/test/clang-tidy/misc-forwarding-reference-overload.cpp
@@ -138,3 +138,25 @@
 private:
   Test6(const Test6 &rhs);
 };
+
+// Do not dereference a null BaseType.
+template <class _Callable> class result_of;
+template <class _Fp, class ..._Args> class result_of<_Fp(_Args...)> { };
+template <class _Tp> using result_of_t = typename result_of<_Tp>::type;
+
+template <class... _Types> struct __overload;
+template <class _Tp, class... _Types>
+struct __overload<_Tp, _Types...> : __overload<_Types...> {
+  using __overload<_Types...>::operator();
+};
+
+template <class _Tp, class... _Types>
+using __best_match_t = typename result_of_t<__overload<_Types...>(_Tp&&)>::type;
+
+template <class... _Types>
+class variant {
+public:
+  template <class _Arg, class _Tp = __best_match_t<_Arg, _Types...> >
+  constexpr variant(_Arg&& __arg) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: constructor accepting a forwarding reference can hide the copy and move constructors
+};