diff -urd -X work2/diff_ignore freeciv.current/ai/aiunit.c work2/ai/aiunit.c
--- freeciv.current/ai/aiunit.c	Sat Aug 25 11:23:36 2001
+++ work2/ai/aiunit.c	Sat Aug 25 19:04:22 2001
@@ -99,18 +99,16 @@
 int could_unit_move_to_tile(struct unit *punit, int src_x, int src_y,
 			    int dest_x, int dest_y)
 {
-  enum move_reason reason;
-  int result;
+  enum unit_move_result result;
 
   result =
-      can_unit_move_to_tile_with_reason(punit->type, unit_owner(punit),
-					punit->activity, punit->connecting,
-					punit->x, punit->y, dest_x, dest_y,
-					0, &reason);
-  if (result)
+      test_unit_move_to_tile(punit->type, unit_owner(punit),
+			     punit->activity, punit->connecting,
+			     punit->x, punit->y, dest_x, dest_y, 0);
+  if (result == MR_OK)
     return 1;
 
-  if (reason == MR_ZOC) {
+  if (result == MR_ZOC) {
     if (could_be_my_zoc(punit, src_x, src_y))
       return -1;
   }
@@ -267,7 +265,7 @@
       if (unknown > most_unknown
 	  && (landnear || !unit_flag(punit->type, F_TRIREME))
 	  && map_get_continent(x1, y1) == con
-	  && can_unit_move_to_tile(punit, x1, y1, 0)
+	  && can_unit_move_to_tile_with_notify(punit, x1, y1, 0)
 	  && !((pcity = map_get_city(x1,y1))
 	       && (unit_flag(punit->type, F_DIPLOMAT)
 		   || unit_flag(punit->type, F_CARAVAN)))
@@ -2240,7 +2238,7 @@
 	y = map_adjust_y(leader->y + dy);
 
 	if (warmap.cost[x][y] > safest
-	    && can_unit_move_to_tile(leader, x, y, FALSE)) {
+	    && can_unit_move_to_tile_with_notify(leader, x, y, FALSE)) {
 	  safest = warmap.cost[x][y];
 	  freelog(LOG_DEBUG, "Barbarian leader: safest is %d, %d, safeness %d",
                   x, y, safest);
diff -urd -X work2/diff_ignore freeciv.current/common/unit.c work2/common/unit.c
--- freeciv.current/common/unit.c	Sat Aug 25 11:23:36 2001
+++ work2/common/unit.c	Sat Aug 25 19:30:54 2001
@@ -1205,6 +1205,17 @@
   return zoc_ok_move_gen(punit, punit->x, punit->y, x, y);
 }
 
+int can_unit_move_to_tile(Unit_Type_id type,
+			  struct player *unit_owner,
+			  enum unit_activity activity,
+			  int connecting, int src_x,
+			  int src_y, int dest_x, int dest_y, int igzoc)
+{
+  return MR_OK == test_unit_move_to_tile(type, unit_owner, activity,
+					 connecting, src_x,
+					 src_y, dest_x, dest_y, igzoc);
+}
+
 /**************************************************************************
   unit can be moved if:
   1) the unit is idle or on goto or connecting.
@@ -1219,38 +1230,32 @@
   9) there is not a peaceful but un-allied city on the target tile
   10) there is no non-allied unit blocking (zoc) [or igzoc is true]
 **************************************************************************/
-int can_unit_move_to_tile_with_reason(Unit_Type_id type,
-				      struct player *unit_owner,
-				      enum unit_activity activity,
-				      int connecting, int src_x, int src_y,
-				      int dest_x, int dest_y, int igzoc,
-				      enum move_reason *reason)
+enum unit_move_result test_unit_move_to_tile(Unit_Type_id type,
+					     struct player *unit_owner,
+					     enum unit_activity activity,
+					     int connecting, int src_x,
+					     int src_y, int dest_x,
+					     int dest_y, int igzoc)
 {
   struct tile *pfromtile, *ptotile;
   int zoc;
   struct city *pcity;
 
-  /* To allow people to pass us NULL if they don't need the reason argument. */
-  enum move_reason dummy;
-  if (!reason) {
-    reason = &dummy;
-  }
-
   /* 1) */
   if (activity != ACTIVITY_IDLE
       && activity != ACTIVITY_GOTO
       && activity != ACTIVITY_PATROL && !connecting) {
-    return 0;
+    return MR_BAD_ACTIVITY;
   }
 
   /* 2) */
   if (!normalize_map_pos(&dest_x, &dest_y)) {
-    return 0;
+    return MR_BAD_MAP_POSITION;
   }
 
   /* 3) */
   if (!is_tiles_adjacent(src_x, src_y, dest_x, dest_y)) {
-    return 0;
+    return MR_BAD_DESTINATION;
   }
 
   pfromtile = map_get_tile(src_x, src_y);
@@ -1258,14 +1263,14 @@
 
   /* 4) */
   if (is_non_allied_unit_tile(ptotile, unit_owner)) {
-    return 0;
+    return MR_DESTINATION_OCCUPIED_BY_NON_ALLIED_UNIT;
   }
 
   if (unit_types[type].move_type == LAND_MOVING) {
     /* 5) */
     if (ptotile->terrain == T_OCEAN &&
 	ground_unit_transporter_capacity(dest_x, dest_y, unit_owner) <= 0) {
-      return 0;
+      return MR_NO_SEA_TRANSPORTER_CAPACITY;
     }
 
     /* Moving from ocean */
@@ -1273,8 +1278,7 @@
       /* 6) */
       if (!unit_flag(type, F_MARINES)
 	  && is_enemy_city_tile(ptotile, unit_owner)) {
-	*reason = MR_INVALID_TYPE_FOR_CITY_TAKE_OVER;
-	return 0;
+	return MR_BAD_TYPE_FOR_CITY_TAKE_OVER;
       }
     }
   } else if (unit_types[type].move_type == SEA_MOVING) {
@@ -1282,21 +1286,20 @@
     if (ptotile->terrain != T_OCEAN
 	&& ptotile->terrain != T_UNKNOWN
 	&& !is_allied_city_tile(ptotile, unit_owner)) {
-	  return 0;
+
+      return MR_DESTINATION_OCCUPIED_BY_NON_ALLIED_CITY;
     }
   }
 
   /* 8) */
   if (is_non_attack_unit_tile(ptotile, unit_owner)) {
-    *reason = MR_NO_WAR;
-    return 0;
+    return MR_NO_WAR;
   }
 
   /* 9) */
   pcity = ptotile->city;
   if (pcity && pplayers_non_attack(city_owner(pcity), unit_owner)) {
-    *reason = MR_NO_WAR;
-    return 0;
+    return MR_NO_WAR;
   }
 
   /* 10) */
@@ -1304,10 +1307,10 @@
       || can_step_taken_wrt_to_zoc(type, unit_owner, src_x,
 				   src_y, dest_x, dest_y);
   if (!zoc) {
-    *reason = MR_ZOC;
+    return MR_ZOC;
   }
 
-  return zoc;
+  return MR_OK;
 }
 
 /*
diff -urd -X work2/diff_ignore freeciv.current/common/unit.h work2/common/unit.h
--- freeciv.current/common/unit.h	Sat Aug 25 11:23:36 2001
+++ work2/common/unit.h	Sat Aug 25 18:53:24 2001
@@ -62,8 +62,12 @@
   ROUTE_GOTO, ROUTE_PATROL
 };
 
-enum move_reason {
-  MR_OTHER, MR_INVALID_TYPE_FOR_CITY_TAKE_OVER, MR_NO_WAR, MR_ZOC
+enum unit_move_result {
+  MR_OK, MR_BAD_TYPE_FOR_CITY_TAKE_OVER, MR_NO_WAR, MR_ZOC,
+  MR_BAD_ACTIVITY, MR_BAD_DESTINATION, MR_BAD_MAP_POSITION,
+  MR_DESTINATION_OCCUPIED_BY_NON_ALLIED_UNIT,
+  MR_NO_SEA_TRANSPORTER_CAPACITY,
+  MR_DESTINATION_OCCUPIED_BY_NON_ALLIED_CITY
 };
 
 enum add_build_city_result {
@@ -241,13 +245,17 @@
 int can_step_taken_wrt_to_zoc(Unit_Type_id type, struct player *unit_owner,
 			      int src_x, int src_y, int dest_x,
 			      int dest_y);
-
-int can_unit_move_to_tile_with_reason(Unit_Type_id type,
-				      struct player *unit_owner,
-				      enum unit_activity activity,
-				      int connecting, int src_x, int src_y,
-				      int dest_x, int dest_y, int igzoc,
-				      enum move_reason *reason);
+int can_unit_move_to_tile(Unit_Type_id type,
+			  struct player *unit_owner,
+			  enum unit_activity activity,
+			  int connecting, int src_x,
+			  int src_y, int dest_x, int dest_y, int igzoc);
+enum unit_move_result test_unit_move_to_tile(Unit_Type_id type,
+					     struct player *unit_owner,
+					     enum unit_activity activity,
+					     int connecting, int src_x,
+					     int src_y, int dest_x,
+					     int dest_y, int igzoc);
 int unit_type_really_ignores_zoc(Unit_Type_id type);
 int zoc_ok_move_gen(struct unit *punit, int x1, int y1, int x2, int y2);
 int zoc_ok_move(struct unit *punit, int x, int y);
diff -urd -X work2/diff_ignore freeciv.current/server/barbarian.c work2/server/barbarian.c
--- freeciv.current/server/barbarian.c	Sat Aug 25 11:23:36 2001
+++ work2/server/barbarian.c	Sat Aug 25 19:04:58 2001
@@ -236,8 +236,9 @@
           send_unit_info( 0, punit2);
           while(1) {
 	    rand_neighbour(x, y, &xu, &yu);
-	    if( can_unit_move_to_tile(punit2, xu, yu, TRUE) ) break;
-	    if( can_unit_move_to_tile(punit2, xb, yb, TRUE) ) {
+	    if (can_unit_move_to_tile_with_notify(punit2, xu, yu, TRUE))
+	      break;
+	    if (can_unit_move_to_tile_with_notify(punit2, xb, yb, TRUE)) {
               xu = xb; yu = yb;
               break;
 	    }
diff -urd -X work2/diff_ignore freeciv.current/server/unithand.c work2/server/unithand.c
--- freeciv.current/server/unithand.c	Sat Aug 25 11:23:36 2001
+++ work2/server/unithand.c	Sat Aug 25 19:08:58 2001
@@ -875,7 +875,7 @@
       packet.action_type = DIPLOMAT_CLIENT_POPUP_DIALOG;
       lsend_packet_diplomat_action(player_reply_dest(pplayer), &packet);
       return 0;
-    } else if (!can_unit_move_to_tile(punit, dest_x, dest_y, igzoc)) {
+    } else if (!can_unit_move_to_tile_with_notify(punit, dest_x, dest_y, igzoc)) {
       notify_player_ex(pplayer, punit->x, punit->y, E_NOEVENT,
 		map_get_terrain(punit->x, punit->y)==T_OCEAN
 			? _("Game: Diplomats cannot act from sea.")
@@ -1014,7 +1014,7 @@
   }
 
   /******* ok now move the unit *******/
-  if(can_unit_move_to_tile(punit, dest_x, dest_y, igzoc) &&
+  if(can_unit_move_to_tile_with_notify(punit, dest_x, dest_y, igzoc) &&
      try_move_unit(punit, dest_x, dest_y)) {
     int src_x = punit->x;
     int src_y = punit->y;
diff -urd -X work2/diff_ignore freeciv.current/server/unittools.c work2/server/unittools.c
--- freeciv.current/server/unittools.c	Sat Aug 25 11:53:27 2001
+++ work2/server/unittools.c	Sat Aug 25 19:16:43 2001
@@ -3047,22 +3047,20 @@
 /**************************************************************************
 ...
 **************************************************************************/
-int can_unit_move_to_tile(struct unit *punit, int dest_x, int dest_y,
-			  int igzoc)
+int can_unit_move_to_tile_with_notify(struct unit *punit, int dest_x,
+				      int dest_y, int igzoc)
 {
-  enum move_reason reason;
-  int result;
+  enum unit_move_result reason;
   int src_x = punit->x, src_y = punit->y;
 
-  result =
-      can_unit_move_to_tile_with_reason(punit->type, unit_owner(punit),
-					punit->activity, punit->connecting,
-					punit->x, punit->y, dest_x, dest_y,
-					igzoc, &reason);
-  if (result)
+  reason =
+      test_unit_move_to_tile(punit->type, unit_owner(punit),
+			     punit->activity, punit->connecting,
+			     punit->x, punit->y, dest_x, dest_y, igzoc);
+  if (reason == MR_OK)
     return 1;
 
-  if (reason == MR_INVALID_TYPE_FOR_CITY_TAKE_OVER) {
+  if (reason == MR_BAD_TYPE_FOR_CITY_TAKE_OVER) {
     char *units_str = get_units_with_flag_string(F_MARINES);
     if (units_str) {
       notify_player_ex(unit_owner(punit), src_x, src_y,
diff -urd -X work2/diff_ignore freeciv.current/server/unittools.h work2/server/unittools.h
--- freeciv.current/server/unittools.h	Mon Aug 13 16:09:42 2001
+++ work2/server/unittools.h	Sat Aug 25 18:56:35 2001
@@ -26,7 +26,8 @@
 
 
 /* move check related */
-int can_unit_move_to_tile(struct unit *punit, int dest_x, int dest_y, int igzoc);
+int can_unit_move_to_tile_with_notify(struct unit *punit, int dest_x,
+				      int dest_y, int igzoc);
 
 
 /* turn update related */