[pushed] c++: Add fixed test [PR81952]

[Marek Polacek via Gcc-patches]

This was fixed by r258755:
PR c++/81311 - wrong C++17 overload resolution.

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

        PR c++/81952

gcc/testsuite/ChangeLog:

        * g++.dg/overload/conv-op4.C: New test.
---
 gcc/testsuite/g++.dg/overload/conv-op4.C | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/overload/conv-op4.C

diff --git a/gcc/testsuite/g++.dg/overload/conv-op4.C 
b/gcc/testsuite/g++.dg/overload/conv-op4.C
new file mode 100644
index 00000000000..80de19549e3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/overload/conv-op4.C
@@ -0,0 +1,22 @@
+// PR c++/81952
+// { dg-do run { target c++11 } }
+
+template <class T>
+struct opt {
+    opt() { }
+    opt(opt const& ) { __builtin_abort (); }
+    opt(opt&& ) { __builtin_abort (); }
+
+    template <class U>
+    opt(U&& ) { }
+};
+
+struct foo 
+{
+    explicit operator opt<int>() { __builtin_abort (); return {}; }
+};
+
+int main()
+{
+    opt<int> o(foo{});
+}

base-commit: dd7813f05df50d2ad8e0dc34503f2dff0b521d89
-- 
2.36.1