PR12057: Allow variadic template pack expansions to cross lambda boundaries.

Rather than adding a ContainsUnexpandedParameterPack bit to essentially every
AST node, we tunnel the bit directly up to the surrounding lambda expression
when we reach a context where an unexpanded pack can not normally appear.
Thus any statement or declaration within a lambda can now potentially contain
an unexpanded parameter pack.

llvm-svn: 160705

1 files changed, 6 insertions, 4 deletions

diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index 73347b2e01d..fc52649b9c1 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -790,10 +790,11 @@ LambdaExpr::LambdaExpr(QualType T,
                        ArrayRef<Expr *> CaptureInits,
                        ArrayRef<VarDecl *> ArrayIndexVars,
                        ArrayRef<unsigned> ArrayIndexStarts,
-                       SourceLocation ClosingBrace)
+                       SourceLocation ClosingBrace,
+                       bool ContainsUnexpandedParameterPack)
   : Expr(LambdaExprClass, T, VK_RValue, OK_Ordinary,
          T->isDependentType(), T->isDependentType(), T->isDependentType(),
-         /*ContainsUnexpandedParameterPack=*/false),
+         ContainsUnexpandedParameterPack),
     IntroducerRange(IntroducerRange),
     NumCaptures(Captures.size()),
     CaptureDefault(CaptureDefault),
@@ -850,7 +851,8 @@ LambdaExpr *LambdaExpr::Create(ASTContext &Context,
                                ArrayRef<Expr *> CaptureInits,
                                ArrayRef<VarDecl *> ArrayIndexVars,
                                ArrayRef<unsigned> ArrayIndexStarts,
-                               SourceLocation ClosingBrace) {
+                               SourceLocation ClosingBrace,
+                               bool ContainsUnexpandedParameterPack) {
   // Determine the type of the expression (i.e., the type of the
   // function object we're creating).
   QualType T = Context.getTypeDeclType(Class);
@@ -863,7 +865,7 @@ LambdaExpr *LambdaExpr::Create(ASTContext &Context,
   return new (Mem) LambdaExpr(T, IntroducerRange, CaptureDefault, 
                               Captures, ExplicitParams, ExplicitResultType,
                               CaptureInits, ArrayIndexVars, ArrayIndexStarts,
-                              ClosingBrace);
+                              ClosingBrace, ContainsUnexpandedParameterPack);
 }
 
 LambdaExpr *LambdaExpr::CreateDeserialized(ASTContext &C, unsigned NumCaptures,