[index] Fix crash when indexing a C++14 PCH/module related to TemplateTemplateParmDecls of alias templates

TemplateTemplateParmDecls of alias templates ended-up serialized as 'file-level decls' which was causing a crash while trying to index a PCH/module file that contained them.
Commit makes sure TemplateTemplateParmDecls are not recorded as such kind of decls.

Fixes crash of rdar://36608297

Differential Revision: https://reviews.llvm.org/D42588

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@323549 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/Index/IndexDecl.cpp b/lib/Index/IndexDecl.cpp
index e14750e046..f1ef6c0ea2 100644
--- a/lib/Index/IndexDecl.cpp
+++ b/lib/Index/IndexDecl.cpp
@@ -664,8 +664,11 @@ public:
 
   bool VisitTemplateDecl(const TemplateDecl *D) {
 
-    // Index the default values for the template parameters.
     const NamedDecl *Parent = D->getTemplatedDecl();
+    if (!Parent)
+      return true;
+
+    // Index the default values for the template parameters.
     if (D->getTemplateParameters() &&
         shouldIndexTemplateParameterDefaultValue(Parent)) {
       const TemplateParameterList *Params = D->getTemplateParameters();
@@ -684,7 +687,7 @@ public:
       }
     }
 
-    return Visit(D->getTemplatedDecl());
+    return Visit(Parent);
   }
 
   bool VisitFriendDecl(const FriendDecl *D) {