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.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160705 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index d009e2f81b..082b2e847f 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -838,6 +838,19 @@ namespace {
       return move(Result);
     }
 
+    ExprResult TransformLambdaExpr(LambdaExpr *E) {
+      LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true);
+      return TreeTransform<TemplateInstantiator>::TransformLambdaExpr(E);
+    }
+
+    ExprResult TransformLambdaScope(LambdaExpr *E,
+                                    CXXMethodDecl *CallOperator) {
+      CallOperator->setInstantiationOfMemberFunction(E->getCallOperator(),
+                                                     TSK_ImplicitInstantiation);
+      return TreeTransform<TemplateInstantiator>::
+         TransformLambdaScope(E, CallOperator);
+    }
+
   private:
     ExprResult transformNonTypeTemplateParmRef(NonTypeTemplateParmDecl *parm,
                                                SourceLocation loc,