Fix bugs 2900276 and 2901145, monster beams hitting their thrower

Switch to the YOU_KILL and MON_KILL macros for determining whether a
beam was fired by a monster or the player (used to decide whether a
beam can hit a monster or the player at its point of origin). This
fixes manticores not using their ability, and also stops electric eels
(and electric eel pallet swaps) from shooting themselves.

1 files changed, 10 insertions, 2 deletions

diff --git a/crawl-ref/source/beam.cc b/crawl-ref/source/beam.cc
index b1027781fe..7ae4688b32 100644
--- a/crawl-ref/source/beam.cc
+++ b/crawl-ref/source/beam.cc
@@ -2006,8 +2006,16 @@ void bolt::affect_cell(bool avoid_self)
     const coord_def old_pos = pos();
     const bool was_solid = feat_is_solid(grd(pos()));
 
-    bool avoid_monster = (avoid_self && thrower == KILL_MON_MISSILE);
-    bool avoid_player  = (avoid_self && thrower != KILL_MON_MISSILE);
+    bool avoid_monster = false;
+    bool avoid_player = false;
+
+    if (avoid_self)
+    {
+        if (YOU_KILL(thrower))
+            avoid_player = true;
+        else if (MON_KILL(thrower))
+            avoid_monster = true;
+    }
 
     if (was_solid)
     {