[c++1z] P0195R2: Support pack-expansion of using-declarations.

This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.

llvm-svn: 290080

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 46573477580..d7613638016 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -113,6 +113,10 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
     if (CGDebugInfo *DI = getDebugInfo())
         DI->EmitUsingDecl(cast<UsingDecl>(D));
     return;
+  case Decl::UsingPack:
+    for (auto *Using : cast<UsingPackDecl>(D).expansions())
+      EmitDecl(*Using);
+    return;
   case Decl::UsingDirective: // using namespace X; [C++]
     if (CGDebugInfo *DI = getDebugInfo())
       DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D));