From: Olivier Goffart <ogoffart@woboq.com>
Date: Thu, 26 May 2016 12:55:34 +0000 (+0000)
Subject: Fix crash while parsing variable template with variadic template arguments
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1dcb4b9133fe4a2f370969ac64cef511e4feb135;p=clang

Fix crash while parsing variable template with variadic template arguments

It is only a crash if the compiler optimize for this!=nullptr because
LocalInstantiationScope::getPartiallySubstitutedPack checks if 'this' is null
(This is crashing when clang is compiled with GCC6)

Differential Revision: http://reviews.llvm.org/D20511

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@270845 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaTemplateVariadic.cpp b/lib/Sema/SemaTemplateVariadic.cpp
index 52a1ad545a..06afe87f51 100644
--- a/lib/Sema/SemaTemplateVariadic.cpp
+++ b/lib/Sema/SemaTemplateVariadic.cpp
@@ -604,7 +604,7 @@ bool Sema::CheckParameterPacksForExpansion(
     //   Template argument deduction can extend the sequence of template 
     //   arguments corresponding to a template parameter pack, even when the
     //   sequence contains explicitly specified template arguments.
-    if (!IsFunctionParameterPack) {
+    if (!IsFunctionParameterPack && CurrentInstantiationScope) {
       if (NamedDecl *PartialPack 
                     = CurrentInstantiationScope->getPartiallySubstitutedPack()){
         unsigned PartialDepth, PartialIndex;
diff --git a/test/SemaCXX/cxx1y-variable-templates_top_level.cpp b/test/SemaCXX/cxx1y-variable-templates_top_level.cpp
index 1e5c98beb9..496ae88873 100644
--- a/test/SemaCXX/cxx1y-variable-templates_top_level.cpp
+++ b/test/SemaCXX/cxx1y-variable-templates_top_level.cpp
@@ -458,3 +458,9 @@ namespace PR19169 {
   template<> int g<double>; // expected-error {{no variable template matches specialization; did you mean to use 'g' as function template instead?}}
 }
 
+#ifndef PRECXX11
+template <typename... Args> struct Variadic_t { };
+template <typename... Args> Variadic_t<Args...> Variadic;
+auto variadic1 = Variadic<>;
+auto variadic2 = Variadic<int, int>;
+#endif