ITypeResolver is now implicitly registered to itself & Merge TypeReso…

…lver check

examples/Cli/AutoCompletion/Program.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using Spectre.Console.Cli;
 
 namespace AutoCompletion;
@@ -14,6 +15,12 @@ internal static class Program
 {
     private static void Main(string[] args)
     {
+        // If we just want to test the completion with f5 in visual studio
+        if (Debugger.IsAttached)
+        {
+            args = new[] { "cli", "complete", "\"Li\"" };
+        }
+
         var app = new CommandApp();
         app.Configure(config => config.AddCommand<LionCommand>("lion"));
 

src/Spectre.Console.Cli/Internal/CommandExecutor.cs

@@ -48,7 +48,7 @@ public async Task<int> Execute(IConfiguration configuration, IEnumerable<string>
         _registrar.RegisterInstance(typeof(IRemainingArguments), parsedResult.Remaining);
 
         // Create the resolver.
-        using (var resolver = new TypeResolverAdapter(_registrar.Build()))
+        using (var resolver = MakeTypeResolverAdapter(_registrar))
         {
             // Get the registered help provider, falling back to the default provider
             // registered above if no custom implementations have been registered.
@@ -114,7 +114,39 @@ private CommandTreeParserResult ParseCommandLineArguments(CommandModel model, Co
         }
 
         return parsedResult;
-    }
+    }
+
+    /// <summary>
+    /// Builds a TypeResolver where the ITypeResolver service is registered to itself.
+    /// This only works when the DI framework is not as bad as the primitive one this library uses internally.
+    /// In case the internal one is used, we have a fallback that uses the built resolver directly.
+    /// </summary>
+    private TypeResolverAdapter MakeTypeResolverAdapter(ITypeRegistrar registrar)
+    {
+        ITypeResolver? builtResolver = null;
+        var isBuilt = false;
+
+        registrar.RegisterLazy(typeof(ITypeResolver), () =>
+        {
+            if (isBuilt && builtResolver is null)
+            {
+                // This should not happen, because it is build before this method is called.
+                throw new InvalidOperationException("The builtResolver has not been initialized.");
+            }
+
+            return builtResolver;
+        });
+
+        builtResolver = registrar.Build();
+
+        // Activates the "InvalidOperationException"  if it is not initialized.
+        // The internal DI framework will call the lazy factory on build.
+        isBuilt = true;
+
+        var adapter = new TypeResolverAdapter(builtResolver);
+        return adapter;
+    }
+
 #pragma warning restore CS8603 // Possible null reference return.
 
     private static string ResolveApplicationVersion(IConfiguration configuration)

src/Spectre.Console.Cli/Internal/Composition/Activators.cs

@@ -73,7 +73,10 @@ public override object Activate(DefaultTypeResolver container)
         for (var i = 0; i < _parameters.Count; i++)
         {
             var parameter = _parameters[i];
-            if (parameter.ParameterType == typeof(DefaultTypeResolver))
+            var isTypeResolver = parameter.ParameterType == typeof(ITypeResolver)
+                || parameter.ParameterType == typeof(DefaultTypeResolver);
+
+            if (isTypeResolver)
             {
                 parameters[i] = container;
             }
@@ -82,12 +85,6 @@ public override object Activate(DefaultTypeResolver container)
                 var resolved = container.Resolve(parameter.ParameterType);
                 if (resolved == null)
                 {
-                    if (parameter.ParameterType == typeof(ITypeResolver))
-                    {
-                        parameters[i] = container;
-                        continue;
-                    }
-
                     if (!parameter.IsOptional)
                     {
                         throw new InvalidOperationException($"Could not find registration for '{parameter.ParameterType.FullName}'.");