From eb50c2d17b5a7ce8eccea635d0bfa14328065a25 Mon Sep 17 00:00:00 2001
From: Benjamin Lorenz <lorenz@math.tu-berlin.de>
Date: Fri, 8 Feb 2019 11:10:59 +0100
Subject: [PATCH] llvm7: pair.h: remove reference specializations

to fix some confusion coming from elements in hash_maps:
/tools/llvm-7.0.1/bin/../include/c++/v1/unordered_map:652:17: error: no viable overloaded '='
        __ref() = __v.__get_value();
        ~~~~~~~ ^ ~~~~~~~~~~~~~~~~~
/tools/llvm-7.0.1/bin/../include/c++/v1/__hash_table:1770:47: note: in instantiation of member function 'std::__1::__hash_value_type<int, pm::Rational>::operator=' requested here
                __cache->__upcast()->__value_ = *__first;
...
../../include/core/polymake/pair.h:107:8: note: candidate function (the implicit copy assignment operator) not viable: no known conversion from 'const pair<const std::__1::__hash_value_type<int, pm::Rational>::key_type, std::__1::__hash_value_type<int, pm::Rational>::mapped_type>' to 'const pair<int &, pm::Rational &>' for 1st argument
struct pair<T1&, T2&> {
---
 lib/core/include/pair.h | 51 -----------------------------------------
 1 file changed, 51 deletions(-)

diff --git a/lib/core/include/pair.h b/lib/core/include/pair.h
index 3c325e62db..526b1ed748 100644
--- a/lib/core/include/pair.h
+++ b/lib/core/include/pair.h
@@ -69,57 +69,6 @@ struct isomorphic_to_second< Data, pair<T1,T2> > : isomorphic_types<typename der
 }
 namespace std {
 
-template <typename T1, typename T2>
-struct pair<T1&, T2> {
-   typedef T1& first_type;
-   typedef T2 second_type;
-   /// data types referred to by the components
-   typedef T1 first_data_type;
-   typedef T2 second_data_type;
-
-   first_type first;
-   second_type second;
-
-   pair(T1& first_arg, const T2& second_arg) : first(first_arg), second(second_arg) {}
-
-   template <typename U1, typename U2>
-   explicit pair(const pair<U1&,U2>& p) : first(p.first), second(p.second) {}
-};
-
-template <typename T1, typename T2>
-struct pair<T1, T2&> {
-   typedef T1 first_type;
-   typedef T2& second_type;
-
-   typedef T1 first_data_type;
-   typedef T2 second_data_type;
-
-   first_type first;
-   second_type second;
-
-   pair(const T1& first_arg, T2& second_arg) : first(first_arg), second(second_arg) {}
-
-   template <typename U1, typename U2>
-   explicit pair(const pair<U1,U2&>& p) : first(p.first), second(p.second) {}
-};
-
-template <typename T1, typename T2>
-struct pair<T1&, T2&> {
-   typedef T1& first_type;
-   typedef T2& second_type;
-
-   typedef T1 first_data_type;
-   typedef T2 second_data_type;
-
-   first_type first;
-   second_type second;
-
-   pair(T1& first_arg, T2& second_arg) : first(first_arg), second(second_arg) {}
-
-   template <typename U1, typename U2>
-   explicit pair(const pair<U1&,U2&>& p) : first(p.first), second(p.second) {}
-};
-
 template <typename T1>
 struct pair<T1, pm::nothing> {
    typedef T1 first_type;
-- 
2.21.0