Remove unnecessary null comparison

Author: handiism

prototype/prototype.dart

@@ -1,16 +1,16 @@
 abstract class Shape {
-  int x;
-  int y;
+  late int x;
+  late int y;
   Shape clone();
 }
 
 class Rectangle implements Shape {
-  int height;
-  int width;
-  int x;
-  int y;
+  late int height;
+  late int width;
+  late int x;
+  late int y;
 
-  int _hashCode;
+  late int _hashCode;
   bool isClone = false;
   String get cloneStatus => isClone ? "is a clone" : "is an original gangster";
 
@@ -32,7 +32,6 @@ class Rectangle implements Shape {
 
   @override
   int get hashCode {
-    if (_hashCode != null) return _hashCode;
     _hashCode = DateTime.now().millisecondsSinceEpoch;
     return _hashCode;
   }

proxy/proxy.dart

@@ -3,7 +3,7 @@ abstract class Subject {
 }
 
 class ExpensiveClass implements Subject {
-  String name;
+  late String name;
 
   ExpensiveClass(this.name);
 
@@ -13,8 +13,8 @@ class ExpensiveClass implements Subject {
 }
 
 class Proxy implements Subject {
-  String _name;
-  ExpensiveClass _sub;
+  late String _name;
+  late ExpensiveClass _sub;
 
   Proxy(this._name);
 
@@ -24,7 +24,6 @@ class Proxy implements Subject {
   }
 
   ExpensiveClass _subject() {
-    if (_sub != null) return _sub;
     print("Creating an instance of ExpensiveClass for the proxy...");
     _sub = ExpensiveClass(_name);
     return _sub;