cancelled yellow lights

Someone reported this one to us.

doc/fixes34.1

@@ -290,6 +290,8 @@ handle polearm wielded prior to mounting the same as one wielded while mounted,
 	and one still used after dismounting like one wielded while not mounted
 non-lawful angels don't chat using lawful messages and shouldn't summon
 	lawful help
+cancelled yellow lights should not explode against other monsters, as well as
+	not exploding against you
 
 
 Platform- and/or Interface-Specific Fixes

src/mhitm.c

@@ -306,8 +306,12 @@ mattackm(magr, mdef)
 		break;
 
 	    case AT_EXPL:
-		strike = 1;	/* automatic hit */
 		res[i] = explmm(magr, mdef, mattk);
+		if (res[i] == MM_MISS) { /* cancelled--no attack */
+		    strike = 0;
+		    attk = 0;
+		} else
+		    strike = 1;	/* automatic hit */
 		break;
 
 	    case AT_ENGL:
@@ -537,6 +541,9 @@ explmm(magr, mdef, mattk)
 {
 	int result;
 
+	if (magr->mcan)
+	    return MM_MISS;
+
 	if(cansee(magr->mx, magr->my))
 		pline("%s explodes!", Monnam(magr));
 	else	noises(magr, mattk);