[c++20] P0780R2: Support pack-expansion of init-captures.

This permits an init-capture to introduce a new pack:

  template<typename ...T> auto x = [...a = T()] { /* a is a pack */ };

To support this, the mechanism for allowing ParmVarDecls to be packs has
been extended to support arbitrary local VarDecls.

llvm-svn: 361300

1 files changed, 7 insertions, 1 deletions

diff --git a/clang/test/SemaTemplate/sizeof-pack.cpp b/clang/test/SemaTemplate/sizeof-pack.cpp
index 4b0c883a24a..274726a2315 100644
--- a/clang/test/SemaTemplate/sizeof-pack.cpp
+++ b/clang/test/SemaTemplate/sizeof-pack.cpp
@@ -1,7 +1,13 @@
 // RUN: %clang_cc1 -std=c++11 -verify %s
-// expected-no-diagnostics
 
 template<int &...Ns> int f() {
   return sizeof...(Ns);
 }
 template int f<>();
+
+template<typename ...T> int g() {
+  return [...x = T()] { // expected-warning 2{{extension}}
+    return sizeof...(x);
+  }();
+}
+template int g<>();