re PR c++/31419 (template user defined conversion operator instantiated for conversion to self)

        PR c++/31419
        * call.c (reference_binding): Don't look for user-defined conversions
        to the same type.

From-SVN: r128102

gcc/cp/ChangeLog

 2007-09-04  Jason Merrill  <jason@redhat.com>
 
+	PR c++/31419
+	* call.c (reference_binding): Don't look for user-defined conversions
+	to the same type.
+
 	PR c++/31411
 	* except.c (initialize_handler_parm): Put a CLEANUP_POINT_EXPR inside
 	the MUST_NOT_THROW_EXPR.

gcc/cp/call.c

@@ -1200,7 +1200,12 @@ reference_binding (tree rto, tree rfrom, tree expr, bool c_cast_p, int flags)
 
       return conv;
     }
-  else if (CLASS_TYPE_P (from) && !(flags & LOOKUP_NO_CONVERSION))
+  /* [class.conv.fct] A conversion function is never used to convert a
+     (possibly cv-qualified) object to the (possibly cv-qualified) same
+     object type (or a reference to it), to a (possibly cv-qualified) base
+     class of that type (or a reference to it).... */
+  else if (CLASS_TYPE_P (from) && !related_p
+	   && !(flags & LOOKUP_NO_CONVERSION))
     {
       /* [dcl.init.ref]
 

gcc/testsuite/g++.dg/conversion/self1.C

+// PR c++/31419
+
+struct B
+{
+  template<typename T>
+  operator T const& () const
+  {
+    return 42;
+  }
+};
+
+B f()
+{
+  return B();
+}