r270845 - Fix crash while parsing variable template with variadic template arguments

[Olivier Goffart via cfe-commits]

Author: ogoffart
Date: Thu May 26 07:55:34 2016
New Revision: 270845

URL: http://llvm.org/viewvc/llvm-project?rev=270845&view=rev
Log:
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

Modified:
    cfe/trunk/lib/Sema/SemaTemplateVariadic.cpp
    cfe/trunk/test/SemaCXX/cxx1y-variable-templates_top_level.cpp

Modified: cfe/trunk/lib/Sema/SemaTemplateVariadic.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateVariadic.cpp?rev=270845&r1=270844&r2=270845&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplateVariadic.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplateVariadic.cpp Thu May 26 07:55:34 2016
@@ -604,7 +604,7 @@ bool Sema::CheckParameterPacksForExpansi
     //   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;

Modified: cfe/trunk/test/SemaCXX/cxx1y-variable-templates_top_level.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1y-variable-templates_top_level.cpp?rev=270845&r1=270844&r2=270845&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/cxx1y-variable-templates_top_level.cpp (original)
+++ cfe/trunk/test/SemaCXX/cxx1y-variable-templates_top_level.cpp Thu May 26 07:55:34 2016
@@ -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