From 42e873e10c8d80dc990f939b760a1a9f5d5366a4 Mon Sep 17 00:00:00 2001
From: Dave Abrahams <dave@boostpro.com>
Date: Mon, 14 Jul 2003 16:22:10 +0000
Subject: [PATCH] various bugfixes.  filter_/transform_iterator were misusing
 enable_if in a non-template context , and iterator_facade needed a forward
 declaration for full conformance.

[SVN r19112]
---
 include/boost/iterator/filter_iterator.hpp    | 12 ++++------
 include/boost/iterator/iterator_facade.hpp    |  8 ++++++-
 include/boost/iterator/transform_iterator.hpp | 22 +++++--------------
 3 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/include/boost/iterator/filter_iterator.hpp b/include/boost/iterator/filter_iterator.hpp
index 5b16bb1..059afc5 100644
--- a/include/boost/iterator/filter_iterator.hpp
+++ b/include/boost/iterator/filter_iterator.hpp
@@ -56,16 +56,12 @@ namespace boost
           satisfy_predicate();
       }
 
-      // don't provide this constructor if UnaryFunction is a
-      // function pointer type.  Too dangerous.
-      filter_iterator(
-          typename iterators::enable_if<
-              is_class<Predicate>
-            , Iterator
-          >::type x
-        , Iterator end = Iterator())
+      filter_iterator(Iterator x, Iterator end = Iterator())
         : super_t(x), m_predicate(), m_end(end)
       {
+          // Don't allow use of this constructor if Predicate is a
+          // function pointer type, since it will be 0.
+          BOOST_STATIC_ASSERT(is_class<Predicate>::value);
           satisfy_predicate();
       }
 
diff --git a/include/boost/iterator/iterator_facade.hpp b/include/boost/iterator/iterator_facade.hpp
index 5683cca..774323e 100644
--- a/include/boost/iterator/iterator_facade.hpp
+++ b/include/boost/iterator/iterator_facade.hpp
@@ -28,7 +28,13 @@
 
 namespace boost
 {
+  // This forward declaration is required for the friend declaration
+  // in iterator_core_access
+  template <class I, class V, class AC, class TC, class R, class D> class iterator_facade;
 
+  // Used as a default template argument internally, merely to
+  // indicate "use the default", this can also be passed by users
+  // explicitly in order to specify that the default should be used.
   struct use_default;
   
   namespace detail
@@ -362,7 +368,7 @@ namespace boost
     , class Value
     , class AccessCategory
     , class TraversalCategory
-    , class Reference   = BOOST_ARG_DEPENDENT_TYPENAME detail::const_qualified_ref<Value, AccessCategory>::type
+    , class Reference   = BOOST_DEDUCED_TYPENAME detail::const_qualified_ref<Value, AccessCategory>::type
     , class Difference  = std::ptrdiff_t
   >
   class iterator_facade
diff --git a/include/boost/iterator/transform_iterator.hpp b/include/boost/iterator/transform_iterator.hpp
index e0ab3dd..47ea9ac 100644
--- a/include/boost/iterator/transform_iterator.hpp
+++ b/include/boost/iterator/transform_iterator.hpp
@@ -115,23 +115,13 @@ namespace boost
     transform_iterator(Iterator const& x, UnaryFunction f)
       : super_t(x), m_f(f) { }
 
-    // don't provide this constructor if UnaryFunction is a
-    // function pointer type.  Too dangerous.
-    transform_iterator(
-      // Sadly, GCC 3.2 seems to choke on the enable_if when
-      // UnaryFunction is a plain function pointer
-#if BOOST_WORKAROUND(__GNUC__, BOOST_TESTED_AT(3)) \
-     && BOOST_WORKAROUND(__GNUC_MINOR__, BOOST_TESTED_AT(2))
-        Iterator const& x
-#else 
-      typename iterators::enable_if<
-          is_class<UnaryFunction>
-        , Iterator const&
-      >::type x
-#endif 
-    )
+    transform_iterator(Iterator const& x)
       : super_t(x)
-    {}
+    {
+        // don't provide this constructor if UnaryFunction is a
+        // function pointer type, since it will be 0.  Too dangerous.
+        BOOST_STATIC_ASSERT(is_class<UnaryFunction>::value);
+    }
 
     template<class OtherIterator>
     transform_iterator(