Fixed possibility to initialize empty strings (and booleans)

src/ldblib.c

@@ -433,8 +433,9 @@ static int db_traceback (lua_State *L) {
   return 1;
 }
 
-static int db_settype (lua_State *L) {
+static int db_registertype (lua_State *L) {
   const char *type = luaL_checkstring(L, 1);
+  luaL_checktype(L, 2, LUA_TTABLE);
   lua_setfield(L, LUA_REGISTRYINDEX, type);
   lua_pop(L, 1);
   lua_pushvalue(L, LUA_REGISTRYINDEX);
@@ -460,7 +461,7 @@ static const luaL_Reg dblib[] = {
   {"setmetatable", db_setmetatable},
   {"setupvalue", db_setupvalue},
   {"traceback", db_traceback},
-  {"settype", db_settype},
+  {"registertype", db_registertype},
   {NULL, NULL}
 };
 

src/lparser.c

@@ -668,13 +668,16 @@ static void ravi_code_typecoersion(LexState *ls, int reg, ravi_type_map tm,
  */
 static void ravi_code_setzero(FuncState *fs, int reg, ravi_type_map ravi_type, TString *usertype) {
   (void) usertype;
-  if (ravi_type == RAVI_TM_FLOAT || ravi_type == RAVI_TM_INTEGER)
+  if (ravi_type == RAVI_TM_FLOAT || ravi_type == RAVI_TM_INTEGER) 
     /* code an instruction to convert in place */
     luaK_codeABC(fs, ravi_type == RAVI_TM_FLOAT ? OP_RAVI_LOADFZ : OP_RAVI_LOADIZ, reg, 0, 0);
+  else if (ravi_type == RAVI_TM_BOOLEAN) 
+    luaK_codeABC(fs, OP_LOADBOOL, reg, 0, 0);
+  else if (ravi_type == RAVI_TM_STRING) 
+    luaK_codeABC(fs, OP_LOADNIL, reg, 0, 0);
   else if ((ravi_type & RAVI_TM_NIL) == 0) {
     char type_map_str[RAVI_TYPEMAP_MAX_LEN];
     raviY_typemap_string(ravi_type, type_map_str);
-
     luaX_syntaxerror(fs->ls, luaO_pushfstring(fs->ls->L, "uninitialized %s in local variable", type_map_str));
   }
 }