<rdar://problem/13806270> A template argument list is a constant-evaluated context.

llvm-svn: 181076
diff --git a/clang/lib/Parse/ParseTemplate.cpp b/clang/lib/Parse/ParseTemplate.cpp
index fd49e7a..84b7df7 100644
--- a/clang/lib/Parse/ParseTemplate.cpp
+++ b/clang/lib/Parse/ParseTemplate.cpp
@@ -1149,6 +1149,9 @@
 ///         template-argument-list ',' template-argument
 bool
 Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
+  // Template argument lists are constant-evaluation contexts.
+  EnterExpressionEvaluationContext EvalContext(Actions,Sema::ConstantEvaluated);
+
   while (true) {
     ParsedTemplateArgument Arg = ParseTemplateArgument();
     if (Tok.is(tok::ellipsis)) {