Teach PackExpansionExpr to keep track of the number of pack expansions
it will expand to, if known. Propagate this information throughout Sema.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123470 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclTemplate.cpp b/lib/AST/DeclTemplate.cpp
index bd91fac..e7902e9 100644
--- a/lib/AST/DeclTemplate.cpp
+++ b/lib/AST/DeclTemplate.cpp
@@ -332,7 +332,8 @@
 
       if (NTTP->isParameterPack())
         E = new (Context) PackExpansionExpr(Context.DependentTy, E,
-                                            NTTP->getLocation());
+                                            NTTP->getLocation(),
+                                            llvm::Optional<unsigned>());
       Arg = TemplateArgument(E);
     } else {
       TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*Param);
diff --git a/lib/AST/TemplateBase.cpp b/lib/AST/TemplateBase.cpp
index f7c4ac8..26c0c08 100644
--- a/lib/AST/TemplateBase.cpp
+++ b/lib/AST/TemplateBase.cpp
@@ -384,7 +384,7 @@
       = cast<PackExpansionExpr>(Argument.getAsExpr());
     Expr *Pattern = Expansion->getPattern();
     Ellipsis = Expansion->getEllipsisLoc();
-    // FIXME: Variadic templates num expansions
+    NumExpansions = Expansion->getNumExpansions();
     return TemplateArgumentLoc(Pattern, Pattern);
   }