[view] Fix bug in drop_front

ldionne · ldionne · commit 4f6931090c89 · 2017-12-01T17:21:32.000-08:00
diff --git a/include/boost/hana/view.hpp b/include/boost/hana/view.hpp
@@ -583,7 +583,8 @@ BOOST_HANA_NAMESPACE_BEGIN
         static constexpr auto apply(View view, N const&) {
             constexpr auto n = N::value;
             constexpr auto Length = decltype(hana::length(view))::value;
-            return detail::sliced(view, hana::range_c<std::size_t, n, Length>);
+            constexpr auto begin = (n > Length ? Length : n);
+            return detail::sliced(view, hana::range_c<std::size_t, begin, Length>);
         }
     };
 

Original file line number	Diff line number	Diff line change
`@@ -583,7 +583,8 @@ BOOST_HANA_NAMESPACE_BEGIN`
`583`	`583`	`static constexpr auto apply(View view, N const&) {`
`584`	`584`	`constexpr auto n = N::value;`
`585`	`585`	`constexpr auto Length = decltype(hana::length(view))::value;`
`586`		`- return detail::sliced(view, hana::range_c<std::size_t, n, Length>);`
	`586`	`+ constexpr auto begin = (n > Length ? Length : n);`
	`587`	`+ return detail::sliced(view, hana::range_c<std::size_t, begin, Length>);`
`587`	`588`	`}`
`588`	`589`	`};`
`589`	`590`