From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Tue, 10 Sep 2019 00:39:53 +0000 (+0000)
Subject: Fix crash mangling an explicit lambda non-type template parameter pack
X-Git-Tag: llvmorg-11-init~9602
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ae6f7bcb367465ba1b97cdcb27d528b49f7b238d;p=platform%2Fupstream%2Fllvm.git

Fix crash mangling an explicit lambda non-type template parameter pack
that is not a pack expansion.

llvm-svn: 371476
---

diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 2a2b491..66bccbe 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -1704,7 +1704,8 @@ void CXXNameMangler::mangleTemplateParamDecl(const NamedDecl *Decl) {
       QualType T = Tn->getType();
       if (Tn->isParameterPack()) {
         Out << "Tp";
-        T = T->castAs<PackExpansionType>()->getPattern();
+        if (auto *PackExpansion = T->getAs<PackExpansionType>())
+          T = PackExpansion->getPattern();
       }
       Out << "Tn";
       mangleType(T);
diff --git a/clang/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp b/clang/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp
index dba10fb..45fdec3 100644
--- a/clang/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp
+++ b/clang/test/CodeGenCXX/mangle-lambda-explicit-template-params.cpp
@@ -54,6 +54,12 @@ inline void collision() {
 }
 void use_collision() { collision(); }
 
+namespace pack_not_pack_expansion {
+  template<typename T, int, T...> struct X;
+  // CHECK: @_ZNK23pack_not_pack_expansion1xMUlTyTtTyTnT_TpTnTL0__ETpTyvE_clIiNS_1XEJfEEEDav
+  inline auto x = []<typename T, template<typename U, T, U...> typename, typename ...V>(){}; void f() { x.operator()<int, X, float>(); }
+}
+
 template<typename> void f() {
   // CHECK: define linkonce_odr {{.*}} @_ZZ1fIiEvvENKUlT_E_clIiEEDaS0_(
   auto x = [](auto){};