Improve our handling of user-defined conversions as part of overload
resolution. There are two sources of problems involving user-defined
conversions that this change eliminates, along with providing simpler
interfaces for checking implicit conversions:

  - It eliminates a case of infinite recursion found in Boost.

  - It eliminates the search for the constructor needed to copy a temporary
    generated by an implicit conversion from overload
    resolution. Overload resolution assumes that, if it gets a value
    of the parameter's class type (or a derived class thereof), there
    is a way to copy if... even if there isn't. We now model this
    properly.




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101680 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaTemplate/constructor-template.cpp b/test/SemaTemplate/constructor-template.cpp
index 82c2aa4..b6ca72e 100644
--- a/test/SemaTemplate/constructor-template.cpp
+++ b/test/SemaTemplate/constructor-template.cpp
@@ -94,3 +94,18 @@
 }
 
 template void default_ctor_inst<int>();
+
+template<typename T>
+struct X5 {
+  X5();
+  X5(const T &);
+};
+
+struct X6 {
+  template<typename T> X6(T);
+};
+
+void test_X5_X6() {
+  X5<X6> tf;
+  X5<X6> tf2(tf);
+}