diff --git a/src/core/org/luaj/vm2/lib/DebugLib.java b/src/core/org/luaj/vm2/lib/DebugLib.java
index fd7c4c3c..5bb9fb6a 100644
--- a/src/core/org/luaj/vm2/lib/DebugLib.java
+++ b/src/core/org/luaj/vm2/lib/DebugLib.java
@@ -796,8 +796,8 @@ public class DebugLib extends TwoArgFunction {
 		        LuaString vn = (Lua.GET_OPCODE(i) == Lua.OP_GETTABLE)  /* name of indexed variable */
 	                    ? p.getlocalname(t + 1, pc)
 	                    : (t < p.upvalues.length ? p.upvalues[t].name : QMARK);
-				name = kname(p, k);
-				return new NameWhat( name.tojstring(), vn != null && vn.eq_b(ENV)? "global": "field" );
+				String jname = kname(p, pc, k);
+				return new NameWhat( jname, vn != null && vn.eq_b(ENV)? "global": "field" );
 			}
 			case Lua.OP_GETUPVAL: {
 				int u = Lua.GETARG_B(i); /* upvalue index */
@@ -816,8 +816,8 @@ public class DebugLib extends TwoArgFunction {
 		    }
 			case Lua.OP_SELF: {
 				int k = Lua.GETARG_C(i); /* key index */
-				name = kname(p, k);
-				return new NameWhat( name.tojstring(), "method" );
+				String jname = kname(p, pc, k);
+				return new NameWhat( jname, "method" );
 			}
 			default:
 				break;
@@ -826,11 +826,20 @@ public class DebugLib extends TwoArgFunction {
 		return null; /* no useful name found */
 	}
 
-	static LuaString kname(Prototype p, int c) {
-		if (Lua.ISK(c) && p.k[Lua.INDEXK(c)].isstring())
-			return p.k[Lua.INDEXK(c)].strvalue();
-		else
-			return QMARK;
+	static String kname(Prototype p, int pc, int c) {
+		if (Lua.ISK(c)) {  /* is 'c' a constant? */
+			LuaValue k = p.k[Lua.INDEXK(c)];
+			if (k.isstring()) {  /* literal constant? */
+				return k.tojstring();  /* it is its own name */
+			} /* else no reasonable name found */
+		} else {  /* 'c' is a register */
+			NameWhat what = getobjname(p, pc, c); /* search for 'c' */
+		    if (what != null && "constant".equals(what.namewhat)) {  /* found a constant name? */
+		      return what.name;  /* 'name' already filled */
+		    }
+		    /* else no reasonable name found */
+		}
+		return "?";  /* no reasonable name found */
 	}
 
 	/*