[C++ PATCH] Add test for c++/72845

[Marek Polacek]

This was crashing because our handling of friend decls with noexcept-specifiers
was broken.  Fixed by fairly recent r270005.

Tested x86_64-linux, applying to trunk.

2019-06-08  Marek Polacek  <pola...@redhat.com>

        PR c++/72845.patch
        * g++.dg/cpp0x/noexcept41.C: New test.

diff --git gcc/testsuite/g++.dg/cpp0x/noexcept41.C 
gcc/testsuite/g++.dg/cpp0x/noexcept41.C
new file mode 100644
index 00000000000..4cd3d8d7854
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp0x/noexcept41.C
@@ -0,0 +1,12 @@
+// PR c++/72845
+// { dg-do compile { target c++11 } }
+
+template <typename> struct g { static const int h = 0; };
+template <typename i> void declval() { static_assert(!g<i>::h,""); }
+template <typename> struct a {
+  template <typename d, typename c>
+  friend auto f(d &&, c &&) noexcept(declval<c>) -> decltype(declval<c>); // { 
dg-error "different exception" }
+};
+template <typename d, typename c> auto f(d &&, c &&) -> decltype(declval<c>);
+struct e {};
+static_assert((e{}, declval<a<int>>),""); // { dg-error "no context to resolve 
type" }