Resistances gained from worn or wielded items also protect inventory

src/insight.c

@@ -1373,18 +1373,28 @@ attributes_enlightenment(int unused_mode UNUSED, int final)
         you_are("magic-protected", from_what(ANTIMAGIC));
     if (Fire_resistance)
         you_are("fire resistant", from_what(FIRE_RES));
+    if (u_adtyp_resistance_obj(AD_FIRE))
+        enl_msg("Your items ", "are", "were", " protected from fire", "");
     if (Cold_resistance)
         you_are("cold resistant", from_what(COLD_RES));
+    if (u_adtyp_resistance_obj(AD_COLD))
+        enl_msg("Your items ", "are", "were", " protected from cold", "");
     if (Sleep_resistance)
         you_are("sleep resistant", from_what(SLEEP_RES));
     if (Disint_resistance)
         you_are("disintegration-resistant", from_what(DISINT_RES));
+    if (u_adtyp_resistance_obj(AD_DISN))
+        enl_msg("Your items ", "are", "were", " protected from disintegration", "");
     if (Shock_resistance)
         you_are("shock resistant", from_what(SHOCK_RES));
+    if (u_adtyp_resistance_obj(AD_ELEC))
+        enl_msg("Your items ", "are", "were", " protected from electric shocks", "");
     if (Poison_resistance)
         you_are("poison resistant", from_what(POISON_RES));
     if (Acid_resistance)
         you_are("acid resistant", from_what(ACID_RES));
+    if (u_adtyp_resistance_obj(AD_ACID))
+        enl_msg("Your items ", "are", "were", " protected from acid", "");
     if (Drain_resistance)
         you_are("level-drain resistant", from_what(DRAIN_RES));
     if (Sick_resistance)

src/trap.c

@@ -187,6 +187,8 @@ erode_obj(
 
     switch (type) {
     case ERODE_BURN:
+        if (uvictim && u_adtyp_resistance_obj(AD_FIRE) && rn2(100))
+            return ER_NOTHING;
         vulnerable = is_flammable(otmp);
         check_grease = FALSE;
         cost_type = COST_BURN;
@@ -202,6 +204,8 @@ erode_obj(
         cost_type = COST_ROT;
         break;
     case ERODE_CORRODE:
+        if (uvictim && u_adtyp_resistance_obj(AD_ACID) && rn2(100))
+            return ER_NOTHING;
         vulnerable = is_corrodeable(otmp);
         is_primary = FALSE;
         cost_type = COST_CORRODE;
@@ -3871,6 +3875,9 @@ acid_damage(struct obj* obj)
     victim = carried(obj) ? &g.youmonst : mcarried(obj) ? obj->ocarry : NULL;
     vismon = victim && (victim != &g.youmonst) && canseemon(victim);
 
+    if (victim == &g.youmonst && u_adtyp_resistance_obj(AD_ACID) && rn2(100))
+        return;
+
     if (obj->greased) {
         grease_protect(obj, (char *) 0, victim);
     } else if (obj->oclass == SCROLL_CLASS && obj->otyp != SCR_BLANK_PAPER) {

src/zap.c

@@ -23,6 +23,7 @@ static boolean zap_steed(struct obj *);
 static void skiprange(int, int *, int *);
 static int zap_hit(int, int);
 static void disintegrate_mon(struct monst *, int, const char *);
+static int adtyp_to_prop(int);
 static void backfire(struct obj *);
 static int zap_ok(struct obj *);
 static void boxlock_invent(struct obj *);
@@ -3965,10 +3966,14 @@ zhitu(int type, int nd, const char *fltxt, xchar sx, xchar sy)
         break;
     case ZT_DEATH:
         if (abstyp == ZT_BREATH(ZT_DEATH)) {
+            boolean disn_prot = u_adtyp_resistance_obj(AD_DISN) && rn2(100);
+
             if (Disint_resistance) {
                 You("are not disintegrated.");
                 monstseesu(M_SEEN_DISINT);
                 break;
+            } else if (disn_prot) {
+                break;
             } else if (uarms) {
                 /* destroy shield; other possessions are safe */
                 (void) destroy_arm(uarms);
@@ -4940,6 +4945,36 @@ break_statue(struct obj *obj)
     return TRUE;
 }
 
+/* convert attack damage AD_foo to property resistance */
+static int
+adtyp_to_prop(int dmgtyp)
+{
+    switch (dmgtyp) {
+    case AD_COLD: return COLD_RES;
+    case AD_FIRE: return FIRE_RES;
+    case AD_ELEC: return SHOCK_RES;
+    case AD_ACID: return ACID_RES;
+    case AD_DISN: return DISINT_RES;
+    default: return 0; /* prop_types start at 1 */
+    }
+}
+
+/* is hero wearing or wielding an object with resistance
+   to attack damage type */
+boolean
+u_adtyp_resistance_obj(int dmgtyp)
+{
+    int prop = adtyp_to_prop(dmgtyp);
+
+    if (!prop)
+        return FALSE;
+
+    if ((u.uprops[prop].extrinsic & (W_ARMOR | W_ACCESSORY | W_WEP)) != 0)
+        return TRUE;
+
+    return FALSE;
+}
+
 /*
  * destroy_strings[dindx][0:singular,1:plural,2:killer_reason]
  *      [0] freezing potion
@@ -4979,6 +5014,10 @@ destroy_one_item(struct obj *obj, int osym, int dmgtyp)
     dmg = dindx = 0;
     quan = 0L;
 
+    /* external worn item protects inventory? */
+    if (u_adtyp_resistance_obj(dmgtyp) && rn2(100))
+        return;
+
     switch (dmgtyp) {
     case AD_COLD:
         if (osym == POTION_CLASS && obj->otyp != POT_OIL) {