! Optimized FindDerivedInterface command slightly

Author: wmjordan

Codist/Controls/SymbolCommands.cs

@@ -48,7 +48,7 @@ internal static async Task FindDerivedClassesAsync(this SemanticContext context,
 		}
 
 		internal static async Task FindSubInterfacesAsync(this SemanticContext context, ISymbol symbol) {
-			var interfaces = (await (symbol as INamedTypeSymbol).FindDerivedInterfacesAsync(context.Document.Project, default).ConfigureAwait(false)).ToList();
+			var interfaces = await (symbol as INamedTypeSymbol).FindDerivedInterfacesAsync(context.Document.Project, default).ConfigureAwait(false);
 			await TH.JoinableTaskFactory.SwitchToMainThreadAsync(default);
 			ShowSymbolMenuForResult(symbol, context, interfaces, R.T_DerivedInterfaces, false);
 		}

Codist/Helpers/CodeAnalysisHelper.SymbolFinder.cs

@@ -150,16 +150,15 @@ public static async Task<List<ISymbol>> FindSymbolInstanceProducerAsync(this ITy
 			return members;
 		}
 
-		public static async Task<List<INamedTypeSymbol>> FindDerivedInterfacesAsync(this ITypeSymbol type, Project project, CancellationToken cancellationToken = default) {
+		/// <summary>Returns interfaces derived from the given interface <paramref name="type"/> in specific <paramref name="project"/>.</summary>
+		public static async Task<List<INamedTypeSymbol>> FindDerivedInterfacesAsync(this INamedTypeSymbol type, Project project, CancellationToken cancellationToken = default) {
 			var compilation = await project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
-			var r = new List<INamedTypeSymbol>();
+			var r = new List<INamedTypeSymbol>(7);
 			foreach (var item in compilation.GlobalNamespace.GetAllTypes(cancellationToken)) {
-				if (item.TypeKind != TypeKind.Interface || item == type) {
-					continue;
-				}
-				var inf = item as INamedTypeSymbol;
-				if (inf.AllInterfaces.Contains(type)) {
-					r.Add(inf);
+				if (item.TypeKind == TypeKind.Interface
+					&& item != type
+					&& item.AllInterfaces.Contains(type)) {
+					r.Add(item);
 				}
 			}
 			return r;