function getState(name, isStatic) {
			const stateMap = stack.at(-1);
			const key = `$${name}`; // to avoid "__proto__".

			if (!stateMap[key]) {
				stateMap[key] = {
					nonStatic: { init: false, get: false, set: false },
					static: { init: false, get: false, set: false },
				};
			}

			return stateMap[key][isStatic ? "static" : "nonStatic"];
		}
Gets state of a given member name.
@param {string} name A name of a member.
@param {boolean} isStatic A flag which specifies that is a static member.
@returns {Object} A state of a given member name.
  - retv.init {boolean} A flag which shows the name is declared as normal member.
  - retv.get {boolean} A flag which shows the name is declared as getter.
  - retv.set {boolean} A flag which shows the name is declared as setter.