Revert non-nullable changes

src/libraries/Microsoft.Extensions.Options/src/OptionsCache.cs

@@ -15,7 +15,7 @@ public class OptionsCache<[DynamicallyAccessedMembers(Options.DynamicallyAccesse
         IOptionsMonitorCache<TOptions>
         where TOptions : class
     {
-        private readonly ConcurrentDictionary<string, Lazy<TOptions>> _cache = new(concurrencyLevel: 1, capacity: 31, StringComparer.Ordinal); // 31 == default capacity
+        private readonly ConcurrentDictionary<string, Lazy<TOptions>> _cache = new ConcurrentDictionary<string, Lazy<TOptions>>(concurrencyLevel: 1, capacity: 31, StringComparer.Ordinal); // 31 == default capacity
 
         /// <summary>
         /// Clears all options instances from the cache.
@@ -35,7 +35,7 @@ public virtual TOptions GetOrAdd(string? name, Func<TOptions> createOptions)
                 throw new ArgumentNullException(nameof(createOptions));
             }
 
-            name ??= Options.DefaultName;
+            name = name ?? Options.DefaultName;
             Lazy<TOptions>? value;
 
 #if NETSTANDARD2_1

src/libraries/Microsoft.Extensions.Options/src/OptionsManager.cs

@@ -15,7 +15,7 @@ public class OptionsManager<[DynamicallyAccessedMembers(Options.DynamicallyAcces
         where TOptions : class
     {
         private readonly IOptionsFactory<TOptions> _factory;
-        private readonly OptionsCache<TOptions> _cache = new(); // Note: this is a private cache
+        private readonly OptionsCache<TOptions> _cache = new OptionsCache<TOptions>(); // Note: this is a private cache
 
         /// <summary>
         /// Initializes a new instance with the specified options configurations.
@@ -36,7 +36,7 @@ public OptionsManager(IOptionsFactory<TOptions> factory)
         /// </summary>
         public virtual TOptions Get(string? name)
         {
-            name ??= Options.DefaultName;
+            name = name ?? Options.DefaultName;
 
             if (!_cache.TryGetValue(name, out TOptions? options))
             {

src/libraries/Microsoft.Extensions.Options/src/OptionsMonitor.cs

@@ -63,7 +63,7 @@ void RegisterSource(IOptionsChangeTokenSource<TOptions> source)
 
         private void InvokeChanged(string? name)
         {
-            name ??= Options.DefaultName;
+            name = name ?? Options.DefaultName;
             _cache.TryRemove(name);
             TOptions options = Get(name);
             if (_onChange != null)
@@ -85,7 +85,7 @@ public TOptions CurrentValue
         /// </summary>
         public virtual TOptions Get(string? name)
         {
-            name ??= Options.DefaultName;
+            name = name ?? Options.DefaultName;
             return _cache.GetOrAdd(name, () => _factory.Create(name));
         }
 

src/libraries/Microsoft.Extensions.Options/src/ValidateOptionsResult.cs

@@ -14,12 +14,12 @@ public class ValidateOptionsResult
         /// <summary>
         /// Result when validation was skipped due to name not matching.
         /// </summary>
-        public static readonly ValidateOptionsResult Skip = new() { Skipped = true };
+        public static readonly ValidateOptionsResult Skip = new ValidateOptionsResult() { Skipped = true };
 
         /// <summary>
         /// Validation was successful.
         /// </summary>
-        public static readonly ValidateOptionsResult Success = new() { Succeeded = true };
+        public static readonly ValidateOptionsResult Success = new ValidateOptionsResult() { Succeeded = true };
 
         /// <summary>
         /// True if validation was successful.