3 small tweaks

Author: Corniel

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "8.0.100",
+    "version": "9.0.x",
     "rollForward": "latestFeature"
   }
 }

src/MiniValidation/MiniValidator.cs

@@ -372,9 +372,8 @@ private static async Task<bool> TryValidateImpl(
         }
 
         // Once we get to this point we have to box the target in order to track whether we've validated it or not
-        if (validatedObjects.ContainsKey(target))
+        if (validatedObjects.TryGetValue(target, out var result))
         {
-            var result = validatedObjects[target];
             // If there's a null result it means this object is the one currently being validated
             // so just skip this reference to it by returning true. If there is a result it means
             // we already validated this object as part of this validation operation.
@@ -503,10 +502,8 @@ private static async Task<bool> TryValidateImpl(
             }
         }
 
-        if (isValid && typeof(IValidatableObject).IsAssignableFrom(targetType))
+        if (isValid && target is IValidatableObject validatable)
         {
-            var validatable = (IValidatableObject)target;
-
             // Reset validation context
             validationContext.MemberName = null;
             validationContext.DisplayName = validationContext.ObjectType.Name;
@@ -519,15 +516,13 @@ private static async Task<bool> TryValidateImpl(
             }
         }
 
-        if (isValid && typeof(IAsyncValidatableObject).IsAssignableFrom(targetType))
-        {
-            var validatable = (IAsyncValidatableObject)target;
-
+        if (isValid && target is IAsyncValidatableObject asyncValidatable)
+		{
             // Reset validation context
             validationContext.MemberName = null;
             validationContext.DisplayName = validationContext.ObjectType.Name;
 
-            var validateTask = validatable.ValidateAsync(validationContext);
+            var validateTask = asyncValidatable.ValidateAsync(validationContext);
             ThrowIfAsyncNotAllowed(validateTask.IsCompleted, allowAsync);
 
             var validatableResults = await validateTask.ConfigureAwait(false);