From a2cd9c5fb84a6dfa8e98de9bf2f2038faef5bb24 Mon Sep 17 00:00:00 2001
From: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Sun, 20 Dec 2015 18:38:30 +0000
Subject: [PATCH] 	PR c++/67411

	* decl2.c (decl_maybe_constant_var_p): A proxy isn't constant.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@231862 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/cp/ChangeLog                               |  5 +++++
 gcc/cp/decl2.c                                 |  3 +++
 .../g++.dg/cpp1y/lambda-generic-const1.C       | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp1y/lambda-generic-const1.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9b8c2ffc6f49..40ae390507d9 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2015-12-20  Jason Merrill  <jason@redhat.com>
+
+	PR c++/67411
+	* decl2.c (decl_maybe_constant_var_p): A proxy isn't constant.
+
 2015-12-18  Patrick Palka  <ppalka@gcc.gnu.org>
 
 	PR c++/68978
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 5ae6266c7e17..1e4282a80670 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -4222,6 +4222,9 @@ decl_maybe_constant_var_p (tree decl)
     return false;
   if (DECL_DECLARED_CONSTEXPR_P (decl))
     return true;
+  if (DECL_VALUE_EXPR (decl))
+    /* A proxy isn't constant.  */
+    return false;
   return (CP_TYPE_CONST_NON_VOLATILE_P (type)
 	  && INTEGRAL_OR_ENUMERATION_TYPE_P (type));
 }
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-generic-const1.C b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-const1.C
new file mode 100644
index 000000000000..8b54578b5245
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-const1.C
@@ -0,0 +1,18 @@
+// PR c++/67411
+// { dg-do compile { target c++14 } }
+
+template <class T>
+void f()
+{
+  int i = 42;
+  [x = i] {
+    [&](auto) {
+      [=] { return x; }();
+    }(1);
+  }();
+}
+
+int main()
+{
+  f<int>();
+}
-- 
2.47.2