C++ PATCH for c++/84802, ICE capturing uninstantiated class

[Jason Merrill]

If A<int> isn't instantiated by the time we build the capture proxy
VAR_DECL, it gets no DECL_SIZE. So make sure it is.

Tested x86_64-pc-linux-gnu, applying to trunk.

commit e979dc834d91e52c0c568f85c2b62ec67dac3cdc
Author: Jason Merrill <ja...@redhat.com>
Date:   Mon Mar 12 01:01:14 2018 -0400

            PR c++/84802 - ICE capturing uninstantiated class.
    
            * lambda.c (build_capture_proxy): Call complete_type.

diff --git a/gcc/cp/lambda.c b/gcc/cp/lambda.c
index de064ffc85e..b3c75c84682 100644
--- a/gcc/cp/lambda.c
+++ b/gcc/cp/lambda.c
@@ -432,6 +432,8 @@ build_capture_proxy (tree member, tree init)
       object = convert (type, ptr);
     }
 
+  complete_type (type);
+
   var = build_decl (input_location, VAR_DECL, name, type);
   SET_DECL_VALUE_EXPR (var, object);
   DECL_HAS_VALUE_EXPR_P (var) = 1;
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-generic-ice9.C b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-ice9.C
new file mode 100644
index 00000000000..a07acfff884
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-ice9.C
@@ -0,0 +1,11 @@
+// PR c++/84802
+// { dg-do compile { target c++14 } }
+
+template <class T> struct A { };
+
+void f (A<int>& ar)
+{
+  [](const auto& x)
+    { return [x]{}(); }
+  (ar);
+}