From 9137a38982207bd527099ac558cc18ab6e8fb619 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Tue, 12 Feb 2019 23:20:49 +0100
Subject: [PATCH] Fixes #38

---
 doc/intrusive.qbk                                     |  1 +
 include/boost/intrusive/detail/ebo_functor_holder.hpp |  6 +++---
 include/boost/intrusive/treap.hpp                     | 10 ++++++----
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/doc/intrusive.qbk b/doc/intrusive.qbk
index b745e50..cb5d075 100644
--- a/doc/intrusive.qbk
+++ b/doc/intrusive.qbk
@@ -3886,6 +3886,7 @@ to be inserted in intrusive containers are allocated using `std::vector` or `std
 *  Fixed bugs:
    *  [@https://github.com/boostorg/intrusive/pull/33 GitHub Pull #33: ['Fix compilation in case if key is void*, again]]
    *  [@https://github.com/boostorg/intrusive/issues/35 GitHub Issue #35: ['key_of_value on treap_set seems to be broken in 1.69]]
+   *  [@https://github.com/boostorg/intrusive/issues/38 GitHub Issue #38: ['treap: Same type for priority and key comparison leads to ambiguous base class error]]
 
 [endsect]
 
diff --git a/include/boost/intrusive/detail/ebo_functor_holder.hpp b/include/boost/intrusive/detail/ebo_functor_holder.hpp
index 27415c1..8883166 100644
--- a/include/boost/intrusive/detail/ebo_functor_holder.hpp
+++ b/include/boost/intrusive/detail/ebo_functor_holder.hpp
@@ -158,7 +158,7 @@ template<typename T>
 struct is_unary_or_binary_function : is_unary_or_binary_function_impl<T>
 {};
 
-template<typename T, bool = is_unary_or_binary_function<T>::value>
+template<typename T, typename Tag = void, bool = is_unary_or_binary_function<T>::value>
 class ebo_functor_holder
 {
    BOOST_COPYABLE_AND_MOVABLE(ebo_functor_holder)
@@ -222,8 +222,8 @@ class ebo_functor_holder
    T t_;
 };
 
-template<typename T>
-class ebo_functor_holder<T, false>
+template<typename T, typename Tag>
+class ebo_functor_holder<T, Tag, false>
    :  public T
 {
    BOOST_COPYABLE_AND_MOVABLE(ebo_functor_holder)
diff --git a/include/boost/intrusive/treap.hpp b/include/boost/intrusive/treap.hpp
index c6b4eb2..5656975 100644
--- a/include/boost/intrusive/treap.hpp
+++ b/include/boost/intrusive/treap.hpp
@@ -66,6 +66,8 @@ struct treap_prio_types
                       >::type                         priority_compare;
 };
 
+struct treap_tag;
+
 /// @endcond
 
 //! The class template treap is an intrusive treap container that
@@ -92,7 +94,7 @@ class treap_impl
    //Use public inheritance to avoid MSVC bugs with closures
    , public detail::ebo_functor_holder
          < typename treap_prio_types<typename ValueTraits::pointer, VoidOrPrioOfValue, VoidOrPrioComp>::priority_compare
-         >
+         , treap_tag>
    /// @endcond
 {
    public:
@@ -104,10 +106,10 @@ class treap_impl
    typedef tree_type                                                 implementation_defined;
    typedef treap_prio_types
       < typename ValueTraits::pointer
-      , VoidOrPrioOfValue, VoidOrPrioComp>                          treap_prio_types_t;
+      , VoidOrPrioOfValue, VoidOrPrioComp>                           treap_prio_types_t;
 
    typedef detail::ebo_functor_holder
-      <typename treap_prio_types_t::priority_compare>                prio_base;
+      <typename treap_prio_types_t::priority_compare, treap_tag>     prio_base;
 
    /// @endcond
 
@@ -173,7 +175,7 @@ class treap_impl
    //!   constructor throws (this does not happen with predefined Boost.Intrusive hooks)
    //!   or the copy constructor of the value_compare/priority_compare objects throw. Basic guarantee.
    treap_impl()
-      : tree_type(), prio_base(priority_compare())
+      : tree_type(), prio_base()
    {}
 
    //! <b>Effects</b>: Constructs an empty container.