Use pattern matching for type check.

.editorconfig

···
 #Style - null/type checks
 dotnet_style_coalesce_expression = true:warning
 dotnet_style_null_propagation = true:warning
-csharp_style_pattern_matching_over_is_with_cast_check = true:silent
-csharp_style_pattern_matching_over_as_with_null_check = true:silent
+csharp_style_pattern_matching_over_is_with_cast_check = true:warning
+csharp_style_pattern_matching_over_as_with_null_check = true:warning
 csharp_style_throw_expression = true:silent
 csharp_style_conditional_delegate_call = true:suggestion
 

osu.Framework/Allocation/IReadOnlyDependencyContainer.cs

···
         /// <returns>The requested dependency, or default(<typeparamref name="T"/>) if not found.</returns>
         internal static T GetValue<T>(this IReadOnlyDependencyContainer container, CacheInfo info)
         {
-            var result = container.Get(typeof(T), info);
-            if (result == null)
-                return default;
+            if (container.Get(typeof(T), info) is T value)
+                return value;
 
-            return (T)container.Get(typeof(T), info);
+            return default;
         }
 
         /// <summary>

osu.Framework/Allocation/ObjectHandle.cs

···
 
             try
             {
-                var value = handle.Target;
-
-                if (value is T)
+                if (handle.Target is T value)
                 {
-                    target = (T)value;
+                    target = value;
                     return true;
                 }
             }

osu.Framework/Graphics/Containers/SearchContainer.cs

···
                 !filterable.FilterTerms.Any(filterTerm =>
                     filterTerm.IndexOf(term, StringComparison.InvariantCultureIgnoreCase) >= 0)).ToArray();
 
-            var hasFilterableChildren = filterable as IHasFilterableChildren;
-
             bool matching = childTerms.Length == 0;
 
             //We need to check the children and should any child match this matches as well
-            if (hasFilterableChildren != null)
+            if (filterable is IHasFilterableChildren hasFilterableChildren)
             {
                 foreach (IFilterable child in hasFilterableChildren.FilterableChildren)
                     matching |= match(child, childTerms, searchActive);

osu.Framework/Graphics/Primitives/RectangleF.cs

···
         /// <returns>This method returns true if obj is a <see cref="RectangleF"/> and its X, Y, Width, and Height properties are equal to the corresponding properties of this <see cref="RectangleF"/>; otherwise, false.</returns>
         /// <param name="obj">The <see cref="System.Object"/> to test.</param>
         /// <filterpriority>1</filterpriority>
-        public override bool Equals(object obj)
-        {
-            if (!(obj is RectangleF))
-                return false;
-
-            RectangleF ef = (RectangleF)obj;
-            return ef.X == X && ef.Y == Y && ef.Width == Width && ef.Height == Height;
-        }
+        public override bool Equals(object obj) => obj is RectangleF rec && Equals(rec);
 
         /// <summary>Tests whether two <see cref="RectangleF"/> structures have equal location and size.</summary>
         /// <returns>This operator returns true if the two specified <see cref="RectangleF"/> structures have equal <see cref="X"/>, <see cref="Y"/>, <see cref="Width"/>, and <see cref="Height"/> properties.</returns>

osu.Framework/Graphics/Primitives/RectangleI.cs

···
         /// <returns>This method returns true if obj is a <see cref="RectangleI"/> and its X, Y, Width, and Height properties are equal to the corresponding properties of this <see cref="RectangleI"/>; otherwise, false.</returns>
         /// <param name="obj">The <see cref="T:System.Object"/> to test. </param>
         /// <filterpriority>1</filterpriority>
-        public override bool Equals(object obj)
-        {
-            if (!(obj is RectangleI))
-                return false;
-
-            RectangleI ef = (RectangleI)obj;
-            return ef.X == X && ef.Y == Y && ef.Width == Width && ef.Height == Height;
-        }
+        public override bool Equals(object obj) => obj is RectangleI rec && Equals(rec);
 
         /// <summary>Tests whether two <see cref="RectangleI"/> structures have equal location and size.</summary>
         /// <returns>This operator returns true if the two specified <see cref="RectangleI"/> structures have equal <see cref="X"/>, <see cref="Y"/>, <see cref="Width"/>, and <see cref="Height"/> properties.</returns>

osu.Framework/Graphics/Sprites/FontUsage.cs

···
 
         public bool Equals(FontUsage other) => string.Equals(Family, other.Family) && string.Equals(Weight, other.Weight) && Italics == other.Italics && Size.Equals(other.Size) && FixedWidth == other.FixedWidth;
 
-        public override bool Equals(object obj)
-        {
-            if (ReferenceEquals(null, obj)) return false;
-
-            return obj is FontUsage other && Equals(other);
-        }
+        public override bool Equals(object obj) => obj is FontUsage other && Equals(other);
 
         public override int GetHashCode()
         {

osu.Framework/Graphics/Sprites/IconUsage.cs

···
 
         public bool Equals(IconUsage other) => Icon == other.Icon && string.Equals(Family, other.Family) && string.Equals(Weight, other.Weight);
 
-        public override bool Equals(object obj)
-        {
-            if (ReferenceEquals(null, obj)) return false;
-
-            return obj is IconUsage other && Equals(other);
-        }
+        public override bool Equals(object obj) => obj is IconUsage other && Equals(other);
 
         public override int GetHashCode()
         {