From: Jason Merrill <jason@redhat.com>
Date: Thu, 10 Apr 2025 18:34:35 +0000 (-0400)
Subject: c++: nested lambda capture pack [PR119345]
X-Git-Tag: basepoints/gcc-16~184
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5957b9919c9ecda6e4ca198086f8bb9ea215232c;p=thirdparty%2Fgcc.git

c++: nested lambda capture pack [PR119345]

tsubst_stmt already registers a local capture proxy as a
local_specialization of both an outer capture proxy and the captured
variable; we also need to do that in add_extra_args.

	PR c++/119345

gcc/cp/ChangeLog:

	* pt.cc (add_extra_args): Also register a specialization
	of the captured variable.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp2a/lambda-targ14.C: New test.
---

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 805b274069b..b7060b4c5aa 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -13748,6 +13748,8 @@ add_extra_args (tree extra, tree args, tsubst_flags_t complain, tree in_decl)
 	      inst = local;
 	  /* else inst is already a full instantiation of the pack.  */
 	  register_local_specialization (inst, gen);
+	  if (is_normal_capture_proxy (gen))
+	    register_local_specialization (inst, DECL_CAPTURED_VARIABLE (gen));
 	}
       gcc_assert (!TREE_PURPOSE (extra));
       extra = TREE_VALUE (extra);
diff --git a/gcc/testsuite/g++.dg/cpp2a/lambda-targ14.C b/gcc/testsuite/g++.dg/cpp2a/lambda-targ14.C
new file mode 100644
index 00000000000..debb15e83f6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/lambda-targ14.C
@@ -0,0 +1,12 @@
+// PR c++/119345
+// { dg-do compile { target c++20 } }
+
+void f(auto... args) {
+  [args...]<int... i> {
+    (..., [args...] { i; });
+  }.template operator()<0>();
+}
+
+int main() {
+  f();
+}