Cleaned up Optional

src/Discord.Net/API/DiscordRawClient.cs

@@ -473,7 +473,7 @@ namespace Discord.API
             if (args.Limit <= 0) throw new ArgumentOutOfRangeException(nameof(args.Limit));
             if (args.Offset < 0) throw new ArgumentOutOfRangeException(nameof(args.Offset));
 
-            int limit = args.Limit.IsSpecified ? args.Limit.Value : int.MaxValue;
+            int limit = args.Limit.GetValueOrDefault(int.MaxValue);
             int offset = args.Offset;
 
             List<GuildMember[]> result;

src/Discord.Net/API/Optional.cs

@@ -1,26 +1,48 @@
-namespace Discord.API
+using System;
+
+namespace Discord.API
 {
+    //Based on https://github.com/dotnet/coreclr/blob/master/src/mscorlib/src/System/Nullable.cs
     public struct Optional<T> : IOptional
     {
+        private readonly T _value;
+
         /// <summary> Gets the value for this paramter, or default(T) if unspecified. </summary>
-        public T Value { get; }
+        public T Value
+        {
+            get
+            {
+                if (!IsSpecified)
+                    throw new InvalidOperationException("This property has no value set.");
+                return _value;
+            }
+        }
         /// <summary> Returns true if this value has been specified. </summary>
         public bool IsSpecified { get; }
 
-        object IOptional.Value => Value;
+        object IOptional.Value => _value;
 
         /// <summary> Creates a new Parameter with the provided value. </summary>
         public Optional(T value)
         {
-            Value = value;
+            _value = value;
             IsSpecified = true;
         }
+        
+        public T GetValueOrDefault() => _value;
+        public T GetValueOrDefault(T defaultValue) => IsSpecified ? _value : default(T);
+
+        public override bool Equals(object other)
+        {
+            if (!IsSpecified) return other == null;
+            if (other == null) return false;
+            return _value.Equals(other);
+        }
+
+        public override int GetHashCode() => IsSpecified ? _value.GetHashCode() : 0;
+        public override string ToString() => IsSpecified ? _value.ToString() : "";
 
-        /// <summary> Implicitly creates a new Parameter from an existing value. </summary>
         public static implicit operator Optional<T>(T value) => new Optional<T>(value);
-        /// <summary> Implicitly creates a new Parameter from an existing value. </summary>
-        public static implicit operator T(Optional<T> param) => param.Value;
-
-        public override string ToString() => IsSpecified ? (Value?.ToString() ?? null) : null;
+        public static implicit operator T(Optional<T> value) => value.Value;
     }
 }