Script: this returns nil after RemoveObject instead of throwing

Because the interpreter throws for every function that is called with a
this parameter that has been removed, this() isn't a function anymore.
The function could stay around so that Call("this") or foo->this()
would still work, but I doubt any script ever did that.

src/script/C4Aul.h

@@ -93,6 +93,7 @@ enum C4AulBCCType
 	AB_GLOBALN, // a named global
 	AB_GLOBALN_SET,
 	AB_PAR,     // Par statement
+	AB_THIS,    // this()
 	AB_FUNC,    // function
 
 	AB_PARN_CONTEXT,

src/script/C4AulExec.cpp

@@ -711,6 +711,13 @@ C4Value C4AulExec::Exec(C4AulBCC *pCPos, bool fPassErrors)
 					pCurVal->Set0();
 				break;
 
+			case AB_THIS:
+				if (!pCurCtx->Obj || !pCurCtx->Obj->Status)
+					PushNullVals(1);
+				else
+					PushPropList(pCurCtx->Obj);
+				break;
+
 			case AB_FOREACH_NEXT:
 			{
 				// This should always hold

src/script/C4AulParse.cpp

@@ -629,6 +629,7 @@ static const char * GetTTName(C4AulBCCType e)
 	case AB_GLOBALN: return "GLOBALN";  // a named global
 	case AB_GLOBALN_SET: return "GLOBALN_SET";
 	case AB_PAR: return "PAR";      // Par statement
+	case AB_THIS: return "THIS";
 	case AB_FUNC: return "FUNC";    // function
 
 	case AB_PARN_CONTEXT: return "AB_PARN_CONTEXT";
@@ -689,7 +690,7 @@ static const char * GetTTName(C4AulBCCType e)
 	case AB_EOFN: return "EOFN";    // end of function
 	case AB_EOF: return "EOF";
 
-	default: return "?";
+	default: assert(false);
 	}
 }
 
@@ -829,6 +830,7 @@ int C4AulParse::GetStackValue(C4AulBCCType eType, intptr_t X)
 	case AB_LOCALN:
 	case AB_GLOBALN:
 	case AB_DUP:
+	case AB_THIS:
 		return 1;
 
 	case AB_Pow:
@@ -1550,7 +1552,7 @@ void C4AulParse::Parse_Function()
 			case AB_STRING:
 				fprintf(stderr, "\t\"%s\"\n", pBCC->Par.s->GetCStr()); break;
 			case AB_DEBUG: case AB_NIL: case AB_RETURN:
-			case AB_PAR:
+			case AB_PAR: case AB_THIS:
 			case AB_ARRAYA: case AB_ARRAYA_SET: case AB_ARRAY_SLICE: case AB_ARRAY_SLICE_SET:
 			case AB_ERR: case AB_EOFN: case AB_EOF:
 				assert(!pBCC->Par.X); fprintf(stderr, "\n"); break;
@@ -2310,6 +2312,15 @@ void C4AulParse::Parse_Expression(int iParentPrio)
 			Parse_Params(1, C4AUL_Par);//FIXME: don't use Parse_Params
 			AddBCC(AB_PAR);
 		}
+		else if (SEqual(Idtf, C4AUL_this))
+		{
+			Shift();
+			if (TokenType == ATT_BOPEN)
+			{
+				Parse_Params(0, Idtf, 0);
+			}
+			AddBCC(AB_THIS);
+		}
 		else if (SEqual(Idtf, C4AUL_Inherited) || SEqual(Idtf, C4AUL_SafeInherited))
 		{
 			Shift();
@@ -2356,11 +2367,7 @@ void C4AulParse::Parse_Expression(int iParentPrio)
 				if (Config.Developer.ExtraWarnings && !FoundFn->GetPublic())
 					Warn("using deprecated function %s", Idtf);
 				Shift();
-				// Function parameters for all functions except "this", which can be used without
-				if (!SEqual(FoundFn->GetName(), C4AUL_this) || TokenType == ATT_BOPEN)
-					Parse_Params(FoundFn->GetParCount(), FoundFn->GetName(), FoundFn);
-				else
-					AddBCC(AB_STACK, FoundFn->GetParCount());
+				Parse_Params(FoundFn->GetParCount(), FoundFn->GetName(), FoundFn);
 				AddBCC(AB_FUNC, (intptr_t) FoundFn);
 			}
 			else

src/script/C4Script.cpp

@@ -168,11 +168,6 @@ C4Value C4AulDefFunc::Exec(C4PropList * p, C4Value pPars[], bool fPassErrors)
 
 //=============================== C4Script Functions ====================================
 
-static C4PropList *Fnthis(C4PropList * _this)
-{
-	return _this;
-}
-
 static C4PropList * FnCreatePropList(C4PropList * _this, C4PropList * prototype)
 {
 	return C4PropList::New(prototype);
@@ -641,8 +636,6 @@ void InitCoreFunctionMap(C4AulScriptEngine *pEngine)
 	F(LocateFunc);
 
 	F(eval);
-
-	F(this);
 	F(GetConstantNameByValue);
 
 	AddFunc(pEngine, "Translate", C4AulExec::FnTranslate);