diff --git a/common/include/partial_range.h b/common/include/partial_range.h
index 51293b0d5..77f8c97af 100644
--- a/common/include/partial_range.h
+++ b/common/include/partial_range.h
@@ -7,6 +7,7 @@
 #pragma once
 #include "dxxsconf.h"
 #include "compiler-begin.h"
+#include "compiler-type_traits.h"
 
 template <typename iterator>
 struct partial_range_t
@@ -40,15 +41,18 @@ namespace boost
 }
 #endif
 
-template <typename T>
-partial_range_t<typename T::iterator> partial_range(T &t, typename T::size_type l)
+template <typename T, typename U>
+typename tt::enable_if<!tt::is_unsigned<U>::value, void>::type partial_range(T &, U) DXX_CXX11_EXPLICIT_DELETE;
+
+template <typename T, typename U>
+typename tt::enable_if<tt::is_unsigned<U>::value, partial_range_t<typename T::iterator>>::type partial_range(T &t, const U &l)
 {
 	auto b = begin(t);
 	return partial_range_t<typename T::iterator>(b, b + l);
 }
 
-template <typename T>
-partial_range_t<typename T::const_iterator> partial_range(const T &t, typename T::size_type l)
+template <typename T, typename U>
+typename tt::enable_if<tt::is_unsigned<U>::value, partial_range_t<typename T::const_iterator>>::type partial_range(const T &t, const U &l)
 {
 	auto b = begin(t);
 	return partial_range_t<typename T::const_iterator>(b, b + l);
diff --git a/common/main/gameseg.h b/common/main/gameseg.h
index a8e7947a1..a5599b4f3 100644
--- a/common/main/gameseg.h
+++ b/common/main/gameseg.h
@@ -49,7 +49,7 @@ struct segmasks
 struct segment_depth_array_t : public array<ubyte, MAX_SEGMENTS> {};
 
 extern int      Highest_vertex_index;                   // Highest index in Vertices and Vertex_active, an efficiency hack
-extern int      Highest_segment_index;          // Highest index in Segments, an efficiency hack
+extern unsigned      Highest_segment_index;          // Highest index in Segments, an efficiency hack
 extern int	Doing_lighting_hack_flag;
 
 extern void compute_center_point_on_side(vms_vector *vp,segment *sp,int side);
diff --git a/similar/main/mglobal.cpp b/similar/main/mglobal.cpp
index 02ccf79ed..ade503c1d 100644
--- a/similar/main/mglobal.cpp
+++ b/similar/main/mglobal.cpp
@@ -52,7 +52,7 @@ int		Num_vertices = 0;
 int		Num_segments = 0;
 
 int		Highest_vertex_index=0;
-int		Highest_segment_index=0;
+unsigned		Highest_segment_index;
 
 //	Translate table to get opposite side of a face on a segment.
 const char	Side_opposite[MAX_SIDES_PER_SEGMENT] = {WRIGHT, WBOTTOM, WLEFT, WTOP, WFRONT, WBACK};