From 9b94cd1b2527c8dc9ec19a8608f2313010e721b5 Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 26 Apr 2012 22:43:24 +0000
Subject: [PATCH] Add a missing ExpressionEvaluationContext for template
 default arguments.  Fixes PR12581.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155670 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Parse/ParseTemplate.cpp                  |  1 +
 lib/Sema/SemaTemplate.cpp                    |  1 +
 test/SemaTemplate/default-expr-arguments.cpp | 11 +++++++++++
 3 files changed, 13 insertions(+)

diff --git a/lib/Parse/ParseTemplate.cpp b/lib/Parse/ParseTemplate.cpp
index f8204d9cda..5c3e2ba589 100644
--- a/lib/Parse/ParseTemplate.cpp
+++ b/lib/Parse/ParseTemplate.cpp
@@ -652,6 +652,7 @@ Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) {
     //   end of the template-parameter-list rather than a greater-than
     //   operator.
     GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
+    EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated);
 
     DefaultArg = ParseAssignmentExpression();
     if (DefaultArg.isInvalid())
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index be59068649..b5b99f978e 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -2562,6 +2562,7 @@ SubstDefaultTemplateArgument(Sema &SemaRef,
                                    SourceRange(TemplateLoc, RAngleLoc));
 
   Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
   return SemaRef.SubstExpr(Param->getDefaultArgument(), AllTemplateArgs);
 }
 
diff --git a/test/SemaTemplate/default-expr-arguments.cpp b/test/SemaTemplate/default-expr-arguments.cpp
index 5d301be2fb..1eefa9f895 100644
--- a/test/SemaTemplate/default-expr-arguments.cpp
+++ b/test/SemaTemplate/default-expr-arguments.cpp
@@ -292,3 +292,14 @@ namespace PR8401 {
     f();
   }
 }
+
+namespace PR12581 {
+  const int a = 0;
+  template < typename > struct A;
+  template < typename MatrixType, int =
+  A < MatrixType >::Flags ? : A < MatrixType >::Flags & a > class B;
+  void
+  fn1 ()
+  {
+  }
+}
-- 
2.40.0