PR c++/82030 - ICE inheriting from multiple lambdas

	PR c++/80767
	* call.c (compare_ics): Handle null candidate.

From-SVN: r251549

gcc/cp/ChangeLog

+2017-08-30  Jason Merrill  <jason@redhat.com>
+
+	PR c++/82030 - ICE inheriting from multiple lambdas
+	PR c++/80767
+	* call.c (compare_ics): Handle null candidate.
+
 2017-08-30  Ville Voutilainen  <ville.voutilainen@gmail.com>
 
 	Make taking the address of an overloaded function a non-deduced context

gcc/cp/call.c

@@ -9561,7 +9561,9 @@ compare_ics (conversion *ics1, conversion *ics2)
 	return 0;
       else if (t1->kind == ck_user)
 	{
-	  if (t1->cand->fn != t2->cand->fn)
+	  tree f1 = t1->cand ? t1->cand->fn : t1->type;
+	  tree f2 = t2->cand ? t2->cand->fn : t2->type;
+	  if (f1 != f2)
 	    return 0;
 	}
       else

gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv12.C

+// PR c++/80767
+// { dg-do compile { target c++11 } }
+
+template <typename T, typename U = T> struct A { using type = U; };
+template <typename F, typename... G> struct B : B<F>::type, B<G...>::type {
+  using type = B;
+  using B<F>::type::operator();
+};
+template <typename F> struct B<F> { using type = F; };
+struct {
+  template <typename... F,
+            typename Overload = typename B<typename A<F>::type...>::type>
+  Overload operator()(F...){}
+} a;
+int main() {
+  auto f = a([](int) {}, [](float) {});
+  f({});
+}